Play Live Radio
Next Up:
Available On Air Stations
Watch Live


Planting Time In The Spring Garden

A tomato ripens on the vine of a San Diego resident's garden. According to Nan Sterman, springtime is a great time to plant and grow tomatoes in your vegetable garden.
Adam McLane
A tomato ripens on the vine of a San Diego resident's garden. According to Nan Sterman, springtime is a great time to plant and grow tomatoes in your vegetable garden.
Planting Time In The Spring Garden
Spring is here, and that means many plants are blooming. We'll find out how to take advantage of the wet winter rains and how to control weeds in your garden.

For more gardening tips, call the Water Conservation Garden's Water Smart Pipeline at 866-962-7021.

MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh, and you're listening to These Days on KPBS. Everywhere you turn in San Diego there are things growing. Spring flowers and shrubs and blossoms are showing up even in places where you usually don't see them. Of course, that also means that weeds and other problem plants are also growing fast this season. So, the garden is definitely calling for some attention. All this hour we'll be taking your calls and questions about planting and maintaining your spring garden, including weed control, how to balance the bug population and whether now is the time to make the water-saving changes you've been thinking about in your garden. My guest is Nan Sterman, garden journalist and author of "California Gardener's Guide Volume II." Nan answers calls for the Water Conservation Garden's Water Smart Pipeline. That’s Tuesday mornings and Thursday mornings. And good morning, Nan.

NAN STERMAN (Garden Journalist): Hi, Maureen. How are you?


CAVANAUGH: I’m quite well, thank you. Now, as I said, we are taking your gardening questions. We’re talking about irrigation, mulching, weeding, preparing soil, anything that’s stumped you in the garden. Or if you’d like to, we’d like to hear what you’re thinking about planting this year and why. Call us at 1-888-895-5727, that’s 1-888-895-KPBS. Now, Nan, I just overheard you saying you were so happy when the rain started coming down.

STERMAN: Oh, yeah, absolutely.

CAVANAUGH: Well, tell – why is that?

STERMAN: Well, because I’ve been planting and planting and planting, trying to get into that window before it gets so hot that I can’t plant anymore. And so I planted a bunch of things. In this last week, I’ve probably planted an additional 40, 50 plants in my garden. I’ve been redoing part of the garden and also, you know, I come across so many wonderful plants in my travels that I sort of have more plants than I really probably should. But I’m always looking for someplace to tuck something else, you know, into and because most of my garden is already planted and irrigated, it takes me awhile to get irrigation because I only do drip irrigation to those new plants. So the rain waters them in for me and I always feel like it’s just a great way to get new plants started.

CAVANAUGH: Tell us a little bit more about how beneficial this wet winter and spring has been for gardens here in San Diego.


STERMAN: Oh, you know, we’ve been so depleted in our water. Plants, you know, they lose water and we think of them – they look fine but they really are drier than they would like to be, not all plants but a lot of the plants, especially our ornamental plants. So to get this extra rain and especially this late in the spring when the weather’s warm, that gives them a whole boost they wouldn’t normally have. Normally, we would’ve had our rains end sometime in March, kind of middle, end of March, so we’re like a whole month ahead in terms of the duration or the – how prolonged our rainy period has been this year.

CAVANAUGH: I think anybody just casually looking around can see that, as I said, San Diego looks a lot greener, there are a lot more spring blossoms than we usually see this time of year.

STERMAN: Well, you know, I don’t know if there’s more blossoms or…


STERMAN: …if it’s just the blossoms are lasting longer so you get…

CAVANAUGH: Could be.

STERMAN: …a bigger impact because things that…


STERMAN: …would’ve stopped living by now are still blooming. Things that would’ve come into bloom now are already blooming. My garden has been amazing this year. The color in my garden is amazing, and I have a very low water garden.

CAVANAUGH: That’s exactly right. Just lasting, that color lasting for…


CAVANAUGH: …so much longer, the spring flowers being, you know, lush so much longer than they usually are.

STERMAN: Yeah, absolutely. Absolutely.

CAVANAUGH: We’re taking your calls at 1-888-895-5727. We’re talking gardening all this hour. Before we get to the first phone call, though, a lot of people have turned their irrigation systems off because of the winter…

STERMAN: Umm-hmm.

CAVANAUGH: …and because we’ve had these late spring rains. When should they start turning them back on?

STERMAN: You know, it depends on how these rain patterns go. When we get to the point where we’re really at the end of the rain, where we’re not getting rain once a week, maybe once every week and a half, then I would look at turning your water on, especially along the coast. If you’re further inland and it gets hot, you know, then you can start supplementing. But so far I – my water’s still off. The only place I’m watering is my new meadow that’s been planted recently. That’s been watered, you know, a couple of times in between the rains. But other than that, I’m still off.

CAVANAUGH: We are taking your calls at 1-888-895-5727. My guest is garden journalist Nan Sterman. Let’s go to the phones. And Mettai – Mettai is calling from Carlsbad. Good morning. Welcome to These Days.

METTAI (Caller, Carlsbad): Good morning. Thank you for taking my call.

CAVANAUGH: You’re very welcome.

METTAI: I have a kind of ten-second introduction. We’re from the east coast. We bought a house here, came to sunny California and I’m totally confused. We have a little backyard. My vegetable garden, tomatoes don’t need water, hydrogenous need less water, part of the backyard is clay and I’m asking a difficult question. Is there an average time like we do three times a week, not now with the rain, like in summer, four minutes some plants die, some plants stay alive. So, sorry, to ask a generic question is there a little formula that you can keep all your plants happy?

STERMAN: I get asked this question all the time, so don’t feel like it’s just you. And, unfortunately, the answer is, no, there’s no specific formula. The best way to figure out whether you’re – it’s time to water or not is to put your finger in the soil and see if it’s damp. You have a mixture of plants in your garden that have different watering needs. Like your tomatoes, they’re going to need to be wet all the time, whereas like the shrubs and the trees, they don’t need to be so wet. So you need to sort of take a step back and start watching your plants and seeing what needs a lot of water and what doesn’t need a lot of water. Cut back on the water, be frugal to start with except for your vegetables. Be frugal to start with and watch the plants. They’ll tell you when they’re getting too dry. You’ll notice the leaves look a little sad, a little droopy maybe, if your plants are at that point, you’ve waited too long, you need to get water on them right away. And, in fact, I use what I call the canary test.

CAVANAUGH: And what…

STERMAN: I wonder if I’ve talked about the canary test before?

CAVANAUGH: Well, if you have, tell us again.

STERMAN: Okay, that’s fine. What you do is every garden, usually your irrigation is broken up into zones so, you know, you have different valves in the garden and when each value goes on, each valve is a zone. That zone of irrigation runs independently of the others. So what you want to do is you want to turn everything – you want to turn one zone off and on your calendar mark the day that you turned it off. And then watch the plants in that zone to see when you see the first one looking kind of sad. That’s your canary, right, like the canary in the coal mine. When you see that, go back and see how many days it took until it started looking sad. If it took ten days then you want to water like every 8 or 9 days because you don’t want it to look sad, you don’t want it to get stressed to that point but you don’t need to water it before then. So you can learn how to – how long to stretch out your irrigation by watching the plants. Now how long to run the water every time? We have so many different kinds of soils in San Diego that, again, you have to learn how to do that by watching, for example, if you’re running your irrigation and there’s water running off the surface, we know we have runoff, that means there’s no more water going into the soil. The soil’s like a sponge. It has air holes. When those holes are filled, the water just runs off. You’re wasting water. Turn it off.

CAVANAUGH: Right. Right.

STERMAN: But like – so if you have clay, that’s going to fill with water real quickly. Water doesn’t percolate through it very quickly so you have to run short periods but maybe multiple short periods until you get water really deep where the roots are. That’s the goal. You want water where the roots are. My garden is sand, water goes right through it.

CAVANAUGH: Now lots of people who don’t have drip irrigation don’t really have the ability to turn off one section or the other.

STERMAN: Sure, they do.


STERMAN: Sure. Of course you do. It doesn’t matter whether you have drip or overhead because your irrigation generally is divided into zones. Everything doesn’t water at the same time. That’s each of those valves, you know, those ugly little pipe things with the…


STERMAN: …black, right?


STERMAN: Each of those controls a section of your irrigation. Those are the valves. And so every valve controls what we call a zone, and you should always plant one zone with plants that need the same amount of water because they’re going to get the same amount of water.

CAVANAUGH: Right, right.

STERMAN: Okay? But you can have a high water zone and a low water zone. And your vegetable garden is going to be your highest water zone.

CAVANAUGH: I see, and how does all this work into water restrictions that we have that are going to be coming into place again this summer?

STERMAN: Okay, so this is a really interesting question. Those water restrictions for almost every water agency apply only to overhead spray, the traditional overhead spray irrigation. They do not apply to drip irrigation and they don’t apply to those new – newer – they call – Well, the brand, we call them MP3 rotators, that’s a – it’s a – I’m sorry, not MP3 rotators, MP rotators. I have teenagers, can you tell? The MP rotators…


STERMAN: …which is Match Precipitation and there are other brands coming along with that style. But those water restrictions don’t apply to those two types of irrigation because they’re higher efficiency. Most water agencies will say that they want you to still water on the same day, so if you’re like every odd day or the even days, whatever, run your irrigation on those days but you’re not limited to the 10 minutes if you have those more efficient types of irrigation.

CAVANAUGH: I’m speaking with Nan Sterman. She’s garden journalist and author of many books, including the new one, "Waterwise Plants for the Southwest,” that’s in collaboration with several co-authors. And we’re taking your calls at 1-888-895-5727 about spring gardening, mulching, weeding, preparing soil, any kind of questions you have, or if you’d like to tell us what you’re thinking about planting this year and why, we’d love to hear it. Once again, that’s 1-888-895-5727. Nancy’s calling us in Rancho Penasquitos. Good morning, Nancy. Welcome to These Days.

NANCY (Caller, Rancho Penasquitos): Good morning.


NANCY: Hi. My problem is that my husband and I disagree about what we’re supposed to with trees and we’ve managed to kill three of them.


NANCY: Yeah. And we’ve got them in – we’ve got retaining walls and whatnot and we put the trees in and we’ve been told start by putting in a gallon every other day to get them started or we’re been told you put just a little bit and drip all the time. And no matter what we do, well, we’ve killed three.

STERMAN: Okay, what kind of trees are we talking about?

NANCY: The first two we killed were what are called strawberry trees.

STERMAN: Yeah, okay, Arbutus unedo, that’s a native. Yeah.

NANCY: And I got it because it’s supposed to be drought tolerant, etcetera. Our whole garden is that way except our vegetable garden.


NANCY: And the other one, honestly, I can’t remember because it died so long ago.


STERMAN: Okay, how quickly…

CAVANAUGH: One unidentified tree.

STERMAN: Yes, it’s got a trunk and leaves and all that.


STERMAN: How long did it take between the time you planted the tree and the time it died?

NANCY: Sort of – The first strawberry tree it – I think it wasn’t getting enough water because it ultimately split and it took, I think, two, three months. The second strawberry tree died within two months. And then the other one that is unknown, died within four months.

STERMAN: Okay, what time of year did you plant?

NANCY: I planted springtime.

STERMAN: Okay. So my first suggestion for you is to plant in fall. Our natives are much, much – you’re much more successful with native plants if you plant them in the fall when the weather cools, just at the beginning of the rainy season because that way they get the whole rainy season so that if you don’t irrigate them appropriately, Mother Nature does. That’s the first thing. In addition, Arbutus trees, Arbutus unedo, the species, the true native, is a bit of a challenging tree. And there’s a variety called Marina that’s actually a hybrid of a couple of different European Arbutus and native Arbutus that seems to be more tolerant of garden conditions. You might have more success with that. The third point is even drought tolerant plants need to be watered regularly for their first one to two years in the ground. They don’t put their roots down deep enough to be that resistant to water stress until they’re a little bit more mature. So your next strategies are try Marina, plant it in the fall, make sure that it stays damp through the first year or two in the ground and you’ll probably have a lot more success.

CAVANAUGH: Thank you. Thank you, Nancy, for the phone call. I wonder, if you’re going to be planting trees, do you kind of need professional help, do you think? Depends who you are, huh?

STERMAN: What do you mean by that? No, I don’t see any reason you need professional help. Not at all.


STERMAN: No, it’s no different than planting anything else. You just need to know how to do it. And there’s tips for planting trees in my book, "California Gardener's Guide Volume II” in the back.

CAVANAUGH: There you go.


CAVANAUGH: We have to take a short break and when we return, we’ll continue to take your calls about spring gardening, whether you’re planning to plant trees or whether you’re planning to pull weeds. Give us a call. We have tips for you, 1-888-895-5727. You’re listening to These Days on KPBS.

CAVANAUGH: I'm Maureen Cavanaugh. You're listening to These Days on KPBS. We’re talking about spring gardening and my guest is Nan Sterman, garden journalist, author of "California Gardener's Guide Volume II” and co-author of the new book, "Waterwise Plants for the Southwest.” We’re taking your calls if you have a question about what to plant or how to control weeds. Our number is 1-888-895-5727. There are a few people who want to get in on the conversation but before we do that, I want to ask a question that another one of our callers who couldn’t stay on the line had: Is it better to water longer but less often or more often but shorter periods?

STERMAN: Longer but less often is the absolute answer.


STERMAN: All right, so when you water, the goal is to keep the roots wet. Why? Because roots are what take water up and transport it up into the plant. So you have to have water at the place where it’s needed. Roots, you want to go deep. If you keep the water really shallow, then the roots stay at the surface where they’re more susceptible to evaporation, stress, getting hurt by being dug, you know, if you put a shovel in the ground, all that kind of stuff. If you have trees, shallow roots are disaster if you have bad wind or whatever. We want roots to go deep. Watering deep encourages deeper roots.

CAVANAUGH: I see. Okay.

STERMAN: Got it?

CAVANAUGH: All right. So it’s sort of a chicken and egg situation. You like the deeper roots but you also have to get the water down there in order to keep those roots deep and also make sure the plant is healthy.

STERMAN: Yeah, yeah. Well, it’s not chicken and egg. You just start watering deep to start with. You want to water deeply and frequently to begin with and then deeply and less often as time goes on.

CAVANAUGH: I see. Okay, let’s take another call. Drew is calling us from San Diego. Good morning, Drew, and welcome to These Days.

DREW (Caller, San Diego): Good morning. Hi, I’ve got a question about hiring a landscaper. I’ve got a couple of rental properties in San Diego with small front yards and I’d like to spruce them up and I’m trying to figure out how to hire a good landscaper and how often I should ask him to come.

CAVANAUGH: Great question, Drew. Thank you.

STERMAN: Drew, are you looking to redesign those landscapes or are you just looking for someone to take care of them?

DREW: Just someone to take care of them. I put automatic sprinklers in two of them so it’s got some basic stuff there but I’d like them to look a bit nicer for the neighborhood and give the tenants something better to look at as they come and go.

STERMAN: So you’re talking about care.

DREW: Yes.

STERMAN: Okay. Oh, my gosh, this is a question everybody has. You know, there are very few people I know, unfortunately, who are really happy with their maintenance people. I think this is a matter of philosophy and I think what you need to do is to sit down with this person and be real clear about what your expectations are and what their expectations are and how you want your space taken care of. So, for example, a lot of – Unfortunately, it’s kind of an entry level – you know, it’s a place a lot of people start with their first businesses whether or not they have any skill. And really you do need some skill and you need some knowledge in order to take care of a landscape appropriately. You need to know not to ball up bushes and shrubs. They have a natural size and shape. They need to be planted with enough room to achieve that natural size and shape rather than be cut into circles and squares and triangles and ridiculous shapes like that. A lot of people who take care of landscapes, when they see grass, for example, that has brown spots, they assume right away that the problem is not enough water so they turn the water up. Well, that’s not necessarily the issue. And turning the water up is not necessarily the answer either. You really want to find out what their education is, what their approach is, does the person who’s a supervisor come with the crew every time? Or does the crew come by themselves? When does – if there’s a supervisor or the person who owns the company, whatever it is, how often do they come out? Do they give direction? There aren’t hard and fast rules but it’s like hiring anybody for any kind of job. You want to know what you’re getting and what you’re paying for. And the cheapest is not always the best. In fact, it’s probably not the best.

CAVANAUGH: Would it make any sense to actually ask for other places where they actually service?

STERMAN: Yes. Absolutely.

CAVANAUGH: And take a look?

STERMAN: Referrals. Absolutely.


STERMAN: Absolutely. Talk to the people. Go see the properties. You know, I’ve seen a lot of landscapes where there’s a new landscape installed and it’s got tons of potential but the person who comes in to take care of it wasn’t – didn’t get a chance to talk to the person who designed it so they don’t know what the intent was and they start, you know, pruning it to death. Well, our current crop of designers, we design differently than the way things used to be designed and we have very clear ideas about what we expect and what we’re designing for. And so the maintenance person needs to know what the goal is, what the intent was, whether this particular plant was supposed to be trimmed and shaped or allowed to go natural, etcetera. So the other thing that’s great about going low water is that low water tends to be really low maintenance.

CAVANAUGH: Right. Oh, that’s – that’s one good thing, huh?

STERMAN: Yes, there’s lots of good things.

CAVANAUGH: I’m speaking with Nan Sterman. She’s a garden journalist. I want to talk – I want to ask you just a couple of really foundational questions about spring gardening. If you’ve got an itch to go out and dig, okay, because you’re seeing this wonderful weather that we’re having. It’s going to warm up as the week goes on. When should – what’s the first thing you should do when you go out in the yard and you behold what’s going on in your garden?

STERMAN: Breathe deep. Breathe deep and look around you and just be quiet for a moment and listen. You know, allow everything else to go away and just sort of be part of the landscape and then what I would do is, I would look around and think, okay, what’s happening in my garden? What do I like? What don’t I like? For example, one of the things that I find for myself is if there’s a place I don’t look at, okay, like my eyes avoid, it takes me a while and I go wait a minute, what’s wrong there? Why is it I don’t want to look at that? And when I go back and look at it, I realize I don’t like the way it looks. So I kind of, you know, subconsciously avoid it but that’s what needs my attention because I want it to look good, I want to be happy looking at that corner. So that’s when I know I’m going to go redo that space.

CAVANAUGH: I see. We’re taking your calls at 1-888-895-5727. You can also post your comments online at Let’s hear from Leo. He’s calling us from UTC. Good morning, Leo. Welcome to These Days.

LEO (Caller, University Towne Center): Good morning.


LEO: Hi. I have a question about oleander. So I moved into a house with my wife recently and I’ve been working the last couple months to remove these oleander trees that have been pretty overgrown. And I’d like to plant a vegetable garden in the place there and I’ve read that compost from oleander is safe but I don’t know about the soil and, you know, if there’s roots left over if there’s any danger of the poison from the trees getting into any vegetables that I have planted there?

STERMAN: You know, this is an interesting question, Leo. Nobody’s ever asked me this before. To my knowledge, it’s the foliage, it’s the leaves that you need to worry about. You can go online. There is a website for toxic plants, I think it’s associated with University of California, and it describes each plant and its toxicity. And it seems to me that oleander does not, you know, there’s no issue with toxins in the soil and there’s no issue with the roots, though I hope you’re digging the whole plant out, including the roots rather than leaving the stumps there.

LEO: I am.

STERMAN: So I suspect that there’s no problem. That said, you know, do your homework and if you’re going to do a vegetable garden, I’d really, really recommend building some raised beds and filling them with soil that is, quote, unquote, the right soil, you know, with the right amount of organic matter in it because chances are the soil you have already is not the best vegetable-growing soil and raised beds are so much easier to garden in than flat dirt.

CAVANAUGH: Well, thank you for the call, Leo. Thanks a lot for that.

LEO: Great. Thanks.

CAVANAUGH: Okay, so you get your raised bed and you’re starting to put in a vegetable garden. What are good vegetables to put in now?

STERMAN: Ooh, all those wonderful vegetables that we love in the summer, tomatoes, peppers, eggplants, basil, all those things are just coming into planting season now. So, squash, what do you like? Cucumbers…


STERMAN: Yeah, you can do carrots. You can do carrots. I wouldn’t do like broccoli, cauliflower, those kinds of plants. We’re probably right at the edge of growing them. And if you were to plant them now, they would be taking up the space that you would put your tomatoes and peppers and all that in. So I just would skip those at this point. You know, you could do beans and peas but I would skip all the cold crops, that’s the Coachella crops, and just go straight for the summer yummies.

CAVANAUGH: Let’s take another call. Chris is calling from San Clemente. Good morning, Chris, and welcome to These Days. Hi, Chris. Oh, Scott. Good morning, Scott.

SCOTT (Caller, San Clemente): Hello?

CAVANAUGH: Hi. What’s your question?

SCOTT: Yeah, hi, thanks for taking my call.


SCOTT: I have a question. We are removing our lawn. We have these big, huge oak trees and, I mean, they’re about two feet in diameter and our lawn isn’t really growing very good. We’re taking that out and we’re kind of putting crushed granite down and raised boxes and, you know, planting garden vegetables in the garden area. But our landscaper that’s going to do the work, he suggested that we take some Roundup and pour some type of a weed killer and kill the grass because it’ll always seem to come up, so, you know, to, you know, just kind of wipe everything out. And I’m kind of concerned about the oak trees. Is it going to – will it hurt the oak trees or the roots that are, you know, only about, I don’t know, three, four inches below the surface?

STERMAN: Well, there’s a number of issues here. First of all, are these oak trees that were there before you put the grass in or did you plant the oak trees?

SCOTT: Oh, they’ve been here, you know, ten thousand years. Yeah, they were – they’ve been there a long time.

STERMAN: Okay, get rid of the grass. You never, ever—excuse me for being preachy—you never, ever plant under oak trees, okay, under mature oak trees. That will kill the oak trees.

SCOTT: Well, that’s why we’re getting rid of it because it never really worked very well.

STERMAN: Well, and it won’t work well for the oak trees. It’ll kill the oak trees. So get rid of the oak trees and then don’t…

CAVANAUGH: You mean get rid of the grass.

STERMAN: I’m sorry. Get rid of the oak trees, sorry. Get rid of the grass. Yes, thank you, Maureen.


STERMAN: And then don’t plant under the oak trees. Don’t plant anything under the oak trees. Okay, so that’s…

CAVANAUGH: I’ve never even heard of this.

STERMAN: Oh, yeah.

CAVANAUGH: It’s so interesting.

STERMAN: Oh, yeah, they’re very, very susceptible to water on their roots, essentially. You’ll kill the oak trees. It’ll take a long – it’ll take some time but they’ll decline. You don’t ever want to plant under mature oak trees. If you want to plant – if you want to have a garden with oak trees and plants underneath it, you have to start by planting at the time you plant the oak trees and plant plants that don’t need water over time. But you do not want to plant under oak – you don’t want to water under oak trees. So that’s one issue. When it comes to getting rid of the grass, what kind of grass do you have? Do you have any sense of that?

SCOTT: Well, yeah, there – it’s a fescue.

STERMAN: It’s fescue.

SCOTT: Yeah.

STERMAN: Do you have Bermuda in it at all?

SCOTT: No. No. Well, they – it’s over a period of time. I’m sure there’s a lot of grass that got, you know, some weeds and everything else that got mixed in with it and we haven’t really – We’ve been planning this project for a long time and so we want to kind of get rid of all the grass so…

STERMAN: Okay, that’s good. That’s a great thing to do. Okay, the reason I’m asking you is if you have fescue, fescue has very short, shallow, very thin roots. You do not need to spray that. You can actually cover it with a layer of mulch, like three, four inches of mulch and it will just decompose underneath. Okay, I call that the smother and cover method.


STERMAN: Now, if you have Bermuda grass, Bermuda grass has those really thick kind of pale white roots. They almost look like potato roots, you know, the roots that sprout from a potato when you’ve had it in the drawer too long?


STERMAN: Okay, you know those ones right?


STERMAN: Okay, those are much more difficult to get rid of and smothering them will not work. Those, unless you’re very, very patient and you’re willing to pull them out over a long period of time, those are the ones that you hit with a little bit of Roundup. But if you’re mostly fescue, I would do the mulch first and I would wait to see whether the Bermuda pops up because it will come up through the mulch. Of course, this is long term. And just treat the Bermuda with the Roundup, if that’s what you need. Your landscaper won’t like this because landscapers want to be in and out real quick. And you can understand that, it’s their business; they want to be done with the project and move on to the next. You know, if you spray Roundup, within four to six weeks, you know, the grass will be gone. It probably will not affect the roots of the oak tree at all because the way Roundup works is it goes in through leaves. You’re not drenching the soil, it’s going in through the leaves of the grass. So as long as you’re not drenching the soil, it probably will not affect the roots of the oak tree.

CAVANAUGH: Okay, thank you, Scott for that. I want to ask you, though, if you use the mulching method…

STERMAN: Umm-hmm.

CAVANAUGH: …that smother and cover thing.

STERMAN: Umm-hmm.

CAVANAUGH: How long will that take to get rid of your lawn?

STERMAN: Four or five, six weeks, depending on the time of year. But, you know, really, you can almost plant right into the mulch.




STERMAN: You know, you don’t really have to wait for the grass to be dead. You might have to dig through it in order to plant things.

CAVANAUGH: And is this a good time to actually try to get rid of your lawn?

STERMAN: Sure. Sure.

CAVANAUGH: Is this a good time of year?

STERMAN: Sure, this is a good time of year to start. If you’re doing the mulch method, you can do that any time of year. If you’re doing – if you have a warm season grass that grow – you always want to – you always – if you’re going to spray Roundup, you always want to do it when the grass is actively growing. So if you have a warm season grass, you want to spray it in the warm months of the year when it’s actively growing. Cool season’s the opposite. So mulch you can do any time of year. If you’re going to solarize—solarize is when you put a layer of plastic over it and you let it bake to death, right? Then you want to do that in the hot months of the year. I would not do that under an oak tree.


STERMAN: You probably couldn’t because it’s probably way too shady anyway.

CAVANAUGH: Right, right. We are taking your calls, 1-888-895-5727, or go online, post your questions. We do have – At, that’s where you can post your questions. We do have an online question. Can I use recycled soapy water on my flowers and vegetable garden?

STERMAN: A little more complex question than they realize. It depends what kind of soap you’re using, and I would never use it on the vegetable garden. You might – you can use it on the flower garden and see if the kind of soap you’re using kills your flowers. If you don’t want to take that chance, what I would do is dilute it and use it on the trees and shrubs because they’re a little tougher. They’re not as susceptible to the kinds of soaps. But I would use, you know, a quote, unquote, biodegradable soap and a lot of them now say – well, as we’re going to more and more gray water, acceptance of gray water, which is essentially what this is, you know, they’re marked as environmentally friendly, blah, blah, blah, blah, blah, you know, all those catch terms. So watch for those.

CAVANAUGH: So we talked about mulching, trying to basically smother a lawn but how should you be preparing your soil now to accept seeds and flowers or in your – I guess you don’t really have to prepare the soil in your vegetable garden except buying prepared soil, is that right?

STERMAN: Well, you’re talking about like if you do a raised bed?

CAVANAUGH: Yes, right.

STERMAN: Yeah. You want to fill it with the really good soil…


STERMAN: …to start with. If you have a raised bed that you’ve been using, you know, and you’re going to plant it again this year, you probably want to add some compost. Whenever I plant, no matter what I’m planting, I always throw in a couple of handfuls, more for bigger plants, of worm castings and in fact…


STERMAN: …I like to use my homemade worm castings. The worms are out the back door. They get the kitchen waste. It all goes around and around. And those are really – You know, you want to make sure you’ve got enough organic matter in the soil for those plants.

CAVANAUGH: I see. Now should you actually avoid walking around in your garden now after rains?

STERMAN: In the first day or two after rains, yes. You want to avoid walking around…


STERMAN: …on the dirt because it will compact the soil and that’s not what we want. We want loose, you know, airy soil. It’ll hurt the soil.

CAVANAUGH: So you wait until your garden dries out and…

STERMAN: A day or two, yeah.

CAVANAUGH: Interesting.

STERMAN: Yeah, and if you absolutely have to walk on the soil, get a piece of plywood or something like that to stand on so you’re dispersing your weight over a larger area.

CAVANAUGH: Okay. All right. Sounds good. Let’s take another call. Joe’s calling us from Clairemont. Good morning, Joe. Welcome to These Days. Ah, Joe couldn’t be with us. I want to ask you, we’re almost at a break so I’ll wait on the weed question and see if we can take a call. Jerry is calling us from Encinitas. Good morning, Jerry. Welcome to These Days.

JERRY (Caller, Encinitas): Thank you very much for taking my call. I just wanted – I know that Nan, in one of her television shows, was visiting a school garden and I know she’s pretty involved with children and gardens. I wanted just maybe to alert and get feedback from Nan about the upcoming School Garden Conference put on by master gardeners in the School Garden program and to also announce that any school who wants to have a master gardener consultant can have one for free just by going on the website and requesting one. But I’d kind of like to get Nan’s input about the value of school gardens.

CAVANAUGH: Great, Jerry, thank you for the call.

STERMAN: Jerry’s a shill, I’m sorry. Jerry…

CAVANAUGH: But it’s a – and a good cause.

STERMAN: It’s a really good – Yes. And he and I talk about this all the time. School gardens are just amazing. You know, they are a way to involve children in so many important issues to get them involved in nature, for them to understand where food comes from, to let them realize that dirt is okay, and also there’s this huge movement now having to do with childhood obesity and so there’s this tight connection between children learning about food and how to grow food and their eating correctly. They’re much more likely to eat their vegetables, their fruits, you know, all their fresh, fresh produce if they grow it themselves and if they begin to understand where it comes from. And so the conference really focuses on helping teachers and parents and volunteers who work with children in school gardens understand and learn about how to make this happen and to learn from each other, too.

CAVANAUGH: We have to take a break but I just want to mention that First Lady Michelle Obama will be in San Diego later this week and she’s going to be talking about obesity and, of course, she famously has planted her own garden…

STERMAN: Umm-hmm. Umm-hmm.

CAVANAUGH: …vegetable garden at the White House to that very end.

STERMAN: Yes, exactly.

CAVANAUGH: Let’s take a break and when we return, we’ll take more of your questions about spring gardening. Our number, 1-888-895-5727. You’re listening to These Days on KPBS.


CAVANAUGH: Welcome back. I'm Maureen Cavanaugh. You're listening to These Days on KPBS. And our show about spring gardening continues. My guest is Nan Sterman, garden journalist, author of "California Gardener's Guide Volume II," co-author of the new book, "Waterwise Plants for the Southwest,” and Nan answers calls for the Water Conservation Garden's Water Smart Pipeline, that’s on Tuesday mornings and Thursday afternoons. The hotline number is 866-962-7021. That’s not our number, our number is 1-888-895-5727 if you’d like to join the conversation, or you can go online, I want to, before we move on to questions because a lot of people want to get into the conversation, talk a little bit about weeds. How have the winter rains, you know, affected this year’s weed population?

STERMAN: Oh, man, just as the plants are, you know, just exploding, so are the weeds. First, let’s talk about what’s a weed.


STERMAN: Okay? A weed is a plant out of place.


STERMAN: All right? There is no inherently bad plant but if there’s a plant growing where you don’t want it and it came there on their – on its own, we tend to call it a weed. Now that said, there’s a lot of weedy plants, plants that sort of spread that we really don’t want growing where they are like grasses and all kinds of other things. So this has been, because it’s been a particularly wet year, it’s a particularly weedy year. What people don’t realize is that—I’m going to get anthropomorphic for a second—a plant’s goal in life is to make babies.


STERMAN: All right. So they make seeds. Fruits have seeds in them. And flowers all becomes seeds, right? So weeds are plants that are very, very successful at making seeds and those seeds set dormant in the soil through the winter and then when the conditions are just right in the spring, the weather’s warm enough, the soil gets warm, there’s enough sunlight or enough hours of sunlight, and it’s wet like we’ve had, those dormant seeds all sprout. They all go ooh! It’s time, let’s go! And they grow. And if they’re annual weeds, they grow real fast because they’ve got to get their entire lifecycle done before the heat comes. They make more seeds, and the next year we have more problem.

CAVANAUGH: Right, exactly.

STERMAN: Umm-hmm.

CAVANAUGH: So what do you do to control weeds? What kind of advice do you give people?

STERMAN: Ah. The minute I notice a weed, I pull it. I have, you know, those white five gallon buckets that you get?


STERMAN: I have those all over my garden. Not like out in the – well, my husband will tell you they’re out in the open but I try to put them in like little spots where you don’t see them. But I have them stashed all over the place because that way as I walk through the yard, and if I see a weed, I pick it right then and there and I stick it in the bucket. And every so often I empty the bucket into the green waste, not into my compost because I don’t want those seeds to sprout in my compost.

CAVANAUGH: Right, right, a very important point. Yes.

STERMAN: So the first thing to do is as soon as you see a weed, pull it. Make sure you pull your weeds before they flower because once they flower, they’re going to make seeds and then your problem is just going to be worse next year. So get at the weeds as soon as you see them and get rid of them right away and then over time, if you do it this year and next year and the next year, in a couple of years, you’ll find your weed population will definitely go down. Okay? One more thing to do?


STERMAN: Mulch, okay?


STERMAN: Put a thick layer of mulch over all of the bare soil because if you do that, you cut the sunlight off and the seeds can’t sprout.


STERMAN: They won’t sprout. They’ll just sit there.

CAVANAUGH: Very good advice. Let’s go to the phones. Eric is calling us from San Diego. Good morning, Eric, and welcome to These Days.

ERIC (Caller, San Diego): Hi. Thanks for taking my call.


ERIC: My question was what time is it best to water? I have a small vegetable garden. We just grow cilantro, tomatoes, onions, things like that. And my dad came from a farming community basically, and he always watered at night but my teacher says it’s best to water in the morning because if you water the plants at night they’re more likely to be prone to frost and die. And I was wondering if that’s true or not.




ERIC: Yeah.

STERMAN: Where do you live?

ERIC: I live in San Diego so I never had to worry about it but my dad, he came from Mexico, so…


ERIC: …I’m not particularly sure.

STERMAN: Okay. All right. Well, it’s interesting. You’re getting the right advice from your teacher but for the wrong reason. Frost doesn’t have anything to do with it. You want to water early in the morning because – are you using – What kind of irrigation are you using?

ERIC: We just – we have – we just use the hose or like a bucket just to pour water over the little vegetables. That’s what we’ve got.

STERMAN: Okay. What you want to make sure is that your plants don’t have wet leaves overnight.


STERMAN: Because they’re mot susceptible to fungi, fungal diseases and all kinds of things like that if they have wet leaves in the cool hours overnight. So you want to water first thing in the morning and besides, then there’s more water for the period of time when the plants are most physiologically active, right? They’re photosynthesizing during the sunlight. So, two reasons. And usually you want to water first thing in the morning.

CAVANAUGH: Thank you for the call, Eric. There’s an online comment, how do you find a good arborist to help with tree removal?

STERMAN: Ahh, well, there is an arborist, there’s a website for the certified arborists. You go on the website and there’s lots of arborists listed there. Tree removal is not an especially high-skill level – Now my arborist friends are going to kill me. But there’s many other things that arborists do that are high skill but removing trees is not necessarily a high skill level project. What’s really, really important is that you talk with your arborist about what they’re going to do with the stump, right? Because you don’t want a big stump left there. Then you have a place you can’t plant or use that’s in the space of a tree. So either you get it ground down or you get it dug out. And grinding it down, you want to get it ground down like a couple of feet down because if it’s just below the surface, again, you can’t plant anything there because you won’t have any soil. And you want to make sure what your expectation is and what their expectation is, and you want to make sure when they’re done that you take a shovel and you dig down and make sure that they’ve ground it down as far as you expect. And if not, you say, hey, job’s not done.

CAVANAUGH: Let’s take another call. Dominick is calling us from Clairemont. Good morning, Dominick. Welcome to These Days.

DOMINICK (Caller, Clairemont): Thank you for taking my call.

CAVANAUGH: You’re welcome.

DOMINICK: Hey, I was looking at some tomatoes at the local nursery and they advise you that you should plant them deep so that almost 80% of the plant is underground. Now is it necessary to pluck off the bottom leaves or just put the whole thing – just kind of, you know, plant them deep.

STERMAN: That’s a great question, Dominick, and let’s back up and talk about why you do that. Tomatoes are the only plant I can think of off the top that you want to plant deeper than they were in the nursery container. Every other plant you want to plant, you know, so that it sits at the same level. But tomatoes are different. You know those little bumps that are on the stem of tomato plants? Have you ever noticed that? Those are all places where roots can develop, so you want to plant the tomato really deep so it establishes a really strong network of roots because all those little bumps will be stimulated to produce additional roots, you get a really strong tomato. And, in fact, if you plant it at an angle, kind of a 45 degree angle, that works really well. So you want to do that and you do – you should probably take the leaves off. If you leave them on, it probably can’t hurt but it’s a better practice to take them off. You can just leave – I mean, when you get the plants planted, you’re going to say, oh, my God, what happened to my tomato plant because there’s only going to be a little tiny bit of the plant sprouting above the soil but that’s okay. They grow so quick that giving it that really good root structure will give you a much better plant overall than if you’d planted it at the same level you started.

CAVANAUGH: We’ve been taking phone calls at 1-888-895-5727 but we’ve also been taking questions online this morning at And we have an online question: How to get rid of – How do you get rid of bamboo?

STERMAN: Heh, you pray to the bamboo gods.

CAVANAUGH: And if they say no, what do you do then?

STERMAN: Well, bamboo’s a grass. Remember the discussion about grass a few minutes ago?

CAVANAUGH: Yes, yes.

STERMAN: Okay. You can dig and you can dig and you can dig and you can dig. You can dig and then when the new little sprouts come up, you can spray those with Roundup if you’re so inclined. You can kill your neighbor who planted the bamboo. If you want some of the bamboo but not all of it, you can, you know, make yourself a perimeter kind of where it’s acceptable and then dig out beyond that and then install a root barrier. My good friend Ralph Evans up at Bamboo Headquarters up in Guajome is the bamboo expert. You can find him online. He’s – It’s Bamboo Headquarters. And Ralph is all things bamboo. So he’s the one you talk to about how to – he has the root barrier, and there’s other places you can get it but that’s a really good way to get it.

CAVANAUGH: One of the things I’m surprised about is we haven’t had any calls about garden pests, bugs. Is it because it’s been so wet that they really haven’t – the bugs really haven’t come out in force yet?

STERMAN: Not because of wet. I think it’s still just a little cool.

CAVANAUGH: I see. I see.

STERMAN: You know, we’re just sort of getting to the – that point of the year when we start having more garden issues, more garden pest issues.

CAVANAUGH: And so I just – there are some aphids, though, that have definitely come out…

STERMAN: Umm-hmm.

CAVANAUGH: …and are haunting people’s vegetables and so forth. What do we do for them?

STERMAN: Ahh, aphids. Well, I’m just – The first thing I think about with aphids is if you grow artichokes, aphids are just like synonymous with artichokes. And so a friend of mine says, oh, they’re just more protein.


STERMAN: When you cut the artichoke bud, what you can do is you can swish the artichoke around in a little bit of water with just a drop of dish soap and some vinegar and it’ll kill the aphids and get off most of them but you’re still going to have some. It’s just – You just can’t get away from them.

CAVANAUGH: Oh, dear.

STERMAN: Aphids are sometimes farmed by ants, so the ants will carry the aphids into your plants and so you want to look around and see if you have ants. And if you have ants, do everything you can to get rid of the ants and then you can wash the aphids off with a little bit of soapy water or a harsh spray. Once those aphid – they have little soft bodies. Once they hit the ground, they’re going to die. You can rub them off, you know, gently. It may not be everybody’s cup of tea but I find it kind of rewarding. You just rub them and they’re so soft they just sort of mush under your fingers. You can rinse them off after that. They’re not the worst pests in the world. Those are good things to do for aphids.

CAVANAUGH: Okay. That sounds good. Let’s try to squeeze in one more call. David is calling from Solana Beach. Good morning, David, and welcome to These Days.

DAVID (Caller, Solana Beach): Good morning. Thank you for taking my call. And, speaking of bugs, I purchased some organic potting soil to grow vegetables in a pot, obviously, and it was full of gnat eggs. I had thousands of them just blooming everywhere. So my question is, how do you choose a good organic potting soil and do I need to throw out that potting soil that I bought and get new ones or can I treat it? Thank you.

STERMAN: Okay, let’s back up for a second. When you say it was full of gnat eggs, did you actually see eggs or did you just see gnats?

DAVID: I saw thousands of gnats that hatched about two weeks after I watered.

STERMAN: Okay, usually those are soil gnats or fungal gnats or – no, soil gnats. Usually they are there because your soil’s too wet and they’re attracted to the wet soil. So they probably were not in the potting mix. They probably, you know, they’re ubiquitous. They’re everywhere. But they probably found that spot because it was the right conditions for them because you kept the surface too wet. One – Are you growing these – These are vegetables you’re growing?

DAVID: And it was grown indoors, so I had total control.

STERMAN: Yes. They’re always worse indoors because outdoors they have pests – I mean, have predators. So what you want to do is you want to get some little tiny gravel, cover the surface with little tiny gravel because that’ll keep a dry surface, and cut back on your watering.

CAVANAUGH: Thank you for the call, David. I don’t want to end this before we have a chance to talk just a tiny little bit about the Encinitas Garden Festival coming up this Saturday. We have about 30 seconds to talk about it. Tell us about it, Nan.

STERMAN: Well, the Encinitas Garden Festival is this annual event. It’s our fifth year. This year, we’re – we have 23 home gardens open in Leucadia. We also have the Paul Ecke School Central – Paul Ecke Central School garden, which is absolutely wonderful. We have the monarch program, which is a butterfly vivarium and a research place for monarch habitat, monarch behavior. We have a fire station and a fire station garden. And we have Jungle Music, which is a palm and cycad grower, who’s going to open his doors for us. The – Our marketplace this year will have all kinds of speakers, I’m speaking, too. That’s at Orpheus Park in Encinitas. And parking is at San Dieguito Academy on Santa Fe Drive because we don’t have room for cars in the neighborhoods. This is a walking tour. But this is the best bang for your buck in all the garden tours, 27 locations to visit in a whole day.

CAVANAUGH: Wow. That’s the Encinitas Garden Festival. It’s this Saturday. It runs from ten to four. You congregate at the parking lot at San Dieguito Academy. If you want to learn more about it, you can go to Nan, thank you so much.

STERMAN: My pleasure, Maureen, and I hope people do go to that website ahead of time because we’d like people to make reservations so we know how many to expect.

CAVANAUGH: Please, continue this discussion about gardening online, You’ve been listening to These Days on KPBS.