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Garden expert Nan Sterman talks about sustainable planting.

March 6, 2012 1:07 p.m.


Nan Sterman, garden designer and author of "California Gardener's Guide Volume II" and "Waterwise Plants for the Southwest." Her website is She also writes a garden column for UT San Diego.

Related Story: Step Into Spring Gardening By Starting Seeds


This is a rush transcript created by a contractor for KPBS to improve accessibility for the deaf and hard-of-hearing. Please refer to the media file as the formal record of this interview. Opinions expressed by guests during interviews reflect the guest’s individual views and do not necessarily represent those of KPBS staff, members or its sponsors.

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CAVANAUGH: This is KPBS Midday Edition. I'm Maureen Cavanaugh. Even though San Diego's climate is pretty garden-friendly all year long, spring inspires everyone to get outside and plant. And the most ambitious way is to start from seed. Nan Sterman is conducting several workshops on how to plant a garden from seed, and other mysteries like how to grow vegetables when you have very little garden space, and how to plant with water conservation in mind. She joins me now to talk about your spring garden, and you can ask her questions in two different ways today. You can give us a call right now. Nan, welcome back.

NAN: Thank you for having me, Maureen.

CAVANAUGH: For those of us who will remain nameless, who remain deeply garden-challenged, what are the different ways that you can start plant something why is starting from seed so challenging?

NAN: Because seeds are very vulnerable. And when you start seeds, you have a pretty -- depending on your knowledge level and skill, and of course that's all practice, you can have a pretty big failure rate. Until you get good at it, you can lose those plants. Whereas when you buy the plants started in the nursery, they're usually pretty sturdy by the time you get them temperature doesn't mean you won't lose some. But you lose more seeds than you do plants.

CAVANAUGH: Why start vegetables and other plants from seeds to begin with?

NAN: Oh, for the challenge! That's part of T. But there's a number of reasons. When is that when you go to the nursery to buy, let's say a tomato plant, they have a limited selection of varieties. When you look at a seed catalog, and there are, you know, a dozen at least companies if not two or three dozen around that have seed catalogs, the number of varieties to choose from is vast. 20, 30, 40 types. And not every time is going to do well here. And if you just think about it, when you go to the market to buy tomatoes, there are different type was tomatoes in the market. You have the round cherry tomatoes, the grape tomatoes. So imagine there are 17 types of grape tomatoes. Some are yellow, origin, hybrid, heirloom. The choices are vast. So it's really fun to try different things.

CAVANAUGH: So what starts now? What's good to start now? Which ones are best to get started from seed?

NAN: That's a great question. So here's kind of the rule of thumb. The plants that we grow that produce for us in the warm weather, okay, that needs that long period, so we'll be harvesting in summer, are the ones that we eat the fruits of. And by fruits, I mean anything that has seeds. Tomatoes, cucumbers, technically they're fruits. Melons, squash, eggplant, all of those. All of those things that you find in the market in summer are what we're planting now because it's going to take them a couple of months until they mature to the point where they start ripening. The parts that we want to eat. Those are the plants that we want to start now. You can still start beans and peas and let uses, but they're going to be done producing earlier, they're going to want to finish before the warm weather hits.

CAVANAUGH: What's involved in starting from seed?

NAN: Oh, it's so cute.

NAN: Well, seeds need three things, basically. In order to sprout. You get an envelope of seeds and they sit there and look at you. Why don't they sprout in the envelope, right? Well, they're dried down to a point of dormancy. They're waiting for three things: Some kind of a material to be planted onto, potting soil. For seeds we want to use seed starting mix. But they need a matrix. The right temperatures, and they need water. And water is pretty much the activating factor. Some seeds need other things like they need the right amount of light, or they might need to be treated by fire. That's why we have things that sprout after fires that just stay dormant in the soil until the fire comes through. Some seeds have to go through the gut of an animal. Think about all the things that we call bird-planted. But the vegetable seeds mostly need only water, something to sprout on, and the right temperature.

CAVANAUGH: That's fascinating.

NAN: I stumped you didn't I!

CAVANAUGH: Yes, you did! It was the birds and the fire that got me.

CAVANAUGH: Jessica is calling from La Mesa. Welcome to the show.

NEW SPEAKER: I was calling, you mentioned about seed catalogs. And I was thinking about the movie, Food Inc., and how they mentioned in that movie how so many seeds are genetically modified, and you mentioned hybrid, I'm not really sure what that is. I was wondering if you could go into detail about maybe if that makes a difference or what exactly is that is, and if it does or doesn't, where could we find seeds that aren't genetically modified?

CAVANAUGH: Thank you, Jessica.

>> Boy, that's a great question. Okay. So let's start with hybrid. All the fruits and vegetables that we eat are hybrid. Different ones are crossed with each other. Whether they're hybridized by nature or they're hybridized because somebody somewhere, I have a tomato seed called mortgage lifter. It was developed by a tomato grower during the depression. And he found one tomato in his garden that was really big. And another that tasted really good. So he took the pollen from the one and crossed it with the other and did it again and again until he got the tomato that he thought was the best tomato. And he started selling that. And other people agreed, and he paid off his mortgage. It's not any different from what nature does.

CAVANAUGH: And what's different from that to genetic engineer something

NAN: Okay. That's a whole different thing. Genetic engineering is when you take DNA from one organism, like, say, I'm just going to say an example. This is isn't what I think anybody does. A fly. And you put the DNA from the fly into the tomato. Okay, that's genetically engineered. That's when you combine organisms that would never cross other normal circumstances. Now, for the most part, the seeds that we -- that are available to us as consumers are not genetically modified. And many companies will say on the envelope, not Mickically modified. The ones that are genetically modified are the ones that are grown for the soy bean commodities and wheat, and all of those commercial crops.

CAVANAUGH: We heard a lot about Monsanto, and genetically altering their seeds but that's not what you find when you go into a store?

NAN: Well, no. As far as I know, that is not what's going into our consumer garden seeds. If you're worried about it, you can always ask the company that you're buying seeds from. And it's really important to buy good seeds. You get what you pay for. A $0.99 package of seeds is going to produce $0.99 of maybe success. But the good seeds are going to cost you $2, $3 for a package, but they're going to be a better quality, they're probably going to be organic, or they're going to see when they're treated or not. And often those packets will say not GMO, but if it doesn't say, you can always call the company.

CAVANAUGH: Steve is calling from San Marcos. Welcome to the program.

NEW SPEAKER: Thank you very much. My question is, I planted some cabbages from seed in the fall. And they developed a lot of foliage. But they're not forming any heads at all. And I wondered if you could shed some light on that.

NAN: Well, there could be a number of things going on. Did you feed them? Did you give them fertilizer?

NEW SPEAKER: When I rotor tilled the soil, I put some fertilize in it.

NAN: And did you continue to feed through the growing season?

NEW SPEAKER: No, I did not.

>> Well, that could be part of your problem. Vegetables in January are very hungry, greedy plants. They're thirsty and greedy. They want plenty of water, and they want plenty of fertilizer. So it could be that part of your issue was that they didn't get to nitrogen, phosphorous, and potassium to get good heads. And we didn't get a lot of rain over the winter. You might have needed to supplement the watering more than you did. It's hard for me to guess without being this, and looking at what the situation is. How -- did you amend the soil, did you add organic matter to the oil too? Did you mulch them? These are critical issues. And without seeing it, it's a little hard. But those are my first thoughts.

CAVANAUGH: You bring up the issue of water now, Nan. If people are trying to save water, but they want to grow these water-hungry vegetables, does that make sense? Does that contradict the conservation that we're all trying to do now with water?

NAN: This is such a great question. I was just in Albuquerque at the international zero scape conference. If you're going to spend water, spend it on something that's going to feed you. Okay? But in addition, I looked at -- I tried to set up a comparison between how much water, let's say, a lawn would take as compared to a vegetable garden. The most water efficient way to grow our vegetables is in raised beds, which are essentially big container, right? If they're four by eight or whatever, you put in the particular kind of soil you like, etc., but you water them, you can plant them very intensely, more intensely than you plant vegetables in the ground, and you water just that. If you were to take your vegetable garden with its beds and plant that area in grass instead, when I did my calculation, it turned out that a vegetable garden takes somewhere between 12-25% as much water, in other words 25 to more% reduction than a lawn in that space.

CAVANAUGH: And there are some low-water lawn seeds on the market now. They have been controversial for a while. What do you think of these products?

NAN: I think the jury is still out. What I've seen is that for 99% of those products, all the products I've seen, they're bred in Massachusetts, Canada, places where there's a lot more water coming out of the sky. So they're low water there because they don't have to supplement or not very much. We only have 11†inches of rainfall. We don't have 30-40 inches. I have yet to see a true turf grass or lawn grass that I feel is sufficiently low water. There are Buffalo grasses and things like that that are more water. They're more like a grassy ground cover than a lawn.

CAVANAUGH: I want to get back to your main cause this spring, and that is trying to teach people how to plant from seed. Do even seasoned gardeners get a little trepidation about --

NAN: Oh, yeah.


NAN: Because it's magic, you know? You don't really know what's going to happen. Even once a little seed sprouts that doesn't mean you're going to have a plant. And that's part of -- the secrets that I talk about in my seed starting workshop,.

CAVANAUGH: But the thing is, do -- is it right for everything all the seeds just to go into the soil even if it's treated first? Should some things be started in pots first?

NAN: Well, most things that I start in pots are things that have the really small seeds like tomatoes, eggplants, peppers, anything -- basil, all of those where the seeds are really tiny, I start those in pots first. Plants that have bigger seeds like squash or pumpkins or cucumbers, you can do them either way. Directly in the ground, in a pot. The thing about starting your seeds in a pot is you can start them much earlier because you can start them inside the house where it's warm, even using a heat mat. Because they want like, 70-degree soil in order to germinate. If I start my seeds in February or March if the house, then 6-eight weeks later, when they're ready to go in the ground, the ground is warm enough that they just take off. If I start my seeds then, it's another 6-eight weeks until they go in the ground.

CAVANAUGH: So if you want a bigger variety of vegetables to choose from, starting from seed is the place to go.

NAN: Yep.

CAVANAUGH: And you are conducting a number of workshops to teach people how to do that.

NAN: I have six more to go.

CAVANAUGH: When is the next one?

NAN: I have one this evening, at BY's ranch, but that's only for their customers. Then I have two this coming weekend. On Saturday, I'm teaching a workshop at southwest stone -- bolder and stone in Pacific Beach. And that's this weekend. And then on Sunday, I'm doing one at olive branch green building supply. The next weekend, I'm going to be at the cosmopolitan restaurant and hotel in old town, and various other places after that.

CAVANAUGH: A full list of Nan's garden workshop dates. You can go to our website, or you can check out Nan's website, And if you'd like to ask Nan a gardening question, you can join her now on our website,