BY TRAINING, Craig LeHoullier is a chemist, but these days his lab is a little different from what you might expect: It’s his driveway, which is positively covered in hundreds of pots. The NC Tomato Man, as he is sometimes called, has trialed more than 2,000 different tomato varieties and introduced more than 100 to the trade, and he even named the popular and distinctive ‘Cherokee Purple,’ in 1990.

This summer, 175ish of those pots and grow bags in Craig’s North Carolina driveway laboratory are tomatoes, and that’s what he talked to me about on my public-radio show and podcast.

Craig is the tomato adviser to Seed Savers Exchange, and author of the bestselling book “Epic Tomatoes,” so whether you’re growing your own or trying to decide among the many distinctive beauties at the local farmers’ market: Craig LeHoullier has the insider info.

Read along as you listen to the July 11, 2016 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

my tomato q&a with craig lehoullier

Q. I’m so grateful that our mutual friend Joe Lamp’l of “Growing a Greener World” public television show introduced us. I was already a fan of the work of you and your colleagues on the Dwarf Tomato Project. Tell us about that.

A. About 20 years ago we started selling seedlings to people in Raleigh, heirloom tomatoes, and one of the most frequently asked questions was, “What do you have that tastes great, but I can grow in a small container?” And the answer was at that time: not much.

So we formed a team right around 2005-2006, my friend Patrina [Nuske] in Australia and I, we employed—employed!—actually, we don’t pay anybody…

Q. [Laughter.]

A. …we’ve gathered about 300 curious, investigative really good gardeners who just want to create something new and different for people. And since 2010 we’ve actually got 60 new dwarf-growing varieties—meaning 3 to 4 feet tall—tomatoes to replicate the colors and flavors of people’s favorite heirlooms.

It’s open source—it’s altruistic—we did it because we love it. We didn’t expect to patent anything or get paid for it. We just can’t wait to get people’s feedback, and see if we’ve done it. Have we filled in a niche in their garden that they’ve been itching to fill?

Q. Before we talk about ripe juicy tomatoes, I was really struck in your book “Epic Tomatoes” at the way all your plants get their start, via what you call a dense planting technique. Explain.

A. The challenge for me is how do I create several thousand seedlings so that we can start spreading heirloom joy around Raleigh through bringing plants to the farmers’ market, though I don’t have a greenhouse? I just have a sunny, south-facing window, and a garage that I can fashion grow lights in, and a sunny driveway.

I just decided let me see how many seeds I can pack into a one-inch cell, go through the transplant process, and get nice, healthy seedlings out the other end. And in doing it that way, in a 1-by-2-foot footprint using a 50-cell plug flat, I can produce between 2,000 and 3,000 healthy seedlings.

Q. Wow.

A. You get the chilled beer open, and the music going, and you get into garage at night and have a little transplant party when it’s time. It’s very therapeutic and it’s fun, and my success rate from seed to healthy seedling is probably 99 percent or greater. It is well detailed in the book.

Q. And a video—isn’t there a YouTube video that shows you doing that?

A. There is; it’s on my website. They’re so crude and just amateurish. You know gardeners always have lists of things and projects that are just infinite…

Q. Oh, no; not me. [Laughter.]

A. One thing on the list is better videos—I’d love to have a video series that takes people through “Epic Tomatoes,” meaning how do we choose tomatoes; how do we start them from seed; what is transplanting; how do we troubleshoot; what do we look for feeding and watering right up through harvest and seed save—just to provide some guidance.

You think of how many gardeners there are, and how many we want there to be. Sometimes all they need is a little dose of confidence to get their hands dirty and give it a try, don’t you think?

Q. You’ve seen and grown and tasted a lot of tomatoes, more than most of us ever will. But it seems like there are a lot of tomatoes out there now. When I started as a garden writer maybe 30 years ago, I don’t feel like there were anywhere near as many. How big is the universe now?

A. We have to thank the Seed Savers Exchange for that remarkable idea they came up with in 1975, because in truth, when they got started, the numbers of tomato varieties were really constricted. It’s not that they didn’t exist—they may have been on individual farms spread throughout the world with no mechanism to bring them into common understanding and sharing.

So the Seed Savers Exchange essentially became a tomato Etsy sort of site; it was a place where people could bring all their wonderful varieties, which meant greater access. Seed catalogs in 1975 may have had 100 or 150 varieties, most of which were red. By 1976, when I joined the Seed Savers, there were literally hundreds of varieties. Now there are maybe 10,000 to 12,000 that’s listed in the Seed Savers catalog, in every color in the rainbow.

Now, there is no doubt many of them are synonyms—the same tomato that has taken on a different name depending on who grew it or where it came from. But they’re got the colorful histories, and it doesn’t really matter if they’re synonyms or not. What matters is we get to grow all this wonderful stuff, save seed, share it with other gardeners, and really tantalize our palettes with this whole range of flavors, which I’m hoping is where you’re going next, because eating tomatoes is where’s it’s at [laughter].

Q. Yes, and so again: Whether we’re at the farmers’ market, or whether we’re going to take notes right now while we listen for what to find seed of for next year, can you kind of curate the list? We don’t have time for all 10,000. [Laughter.] Like really tart ones, or really sweet ones—I don’t know how to do it, but some hit parade?

A. You just led in with a really great statement, because I’ve found after tasting a few thousand varieties of tomatoes that the color and the size and the flavors don’t correlate so much as that each variety has genes in it that give it a particular flavor.

That means knowing the names is important—for example, ‘Anna Russian’ will be attractive to people who like a sweet tomato. Or ‘Big Rainbow,’ the big yellow ones with the red swirls.

‘Brandywine,’ ‘Cherokee Purple,’ or ‘Lillian’s Yellow’ will be for those people who want their tastebuds literally assaulted with a jackhammer. You have to love tomatoes, because when you taste that tomato, it is tomato-times-10 flavor.

Q. [Laughter.]

A. We also each taste slightly different. Some people’s sweet is another person’s tart; some people’s intense is another person’s mild. So I would say the best thing is for people to get themselves to a local tomato tasting where you get little bits of tomatoes, and get to make notes on paper, and then you start finding out what it is that you like.

Google’s your friend at that point (or even email me at nctomatoman [at] gmail [dot] com—I love to be people’s travel master for folks to discover things.

A lot of people ask for the tart, old-fashioned tomatoes of their youth, and really what they’re looking for is tomatoes that have a lower sugar level. A great study that was done about 20 years ago by the USDA uncovered the fact that all tomatoes have about equivalent acidity, however vastly varying sugar levels.

When we taste a tomato we are actually tasting the absence or presence of sugar, rather than the absence or presence of acid.

Q. I see; but it reads to us as acidic. Makes sense.

I love cherry tomatoes, and to use for all kinds of purposes. I make sauce of them or eat them right in the garden or whatever. When I say cherry tomato I know there are grape tomatoes and smaller ones and slight larger ones, so among small tomatoes—any favorites? I’m a ‘Sun Gold’ lover and that’s a hybrid, and I know some people say, “I don’t want a hybrid.”

A. ‘Sun Gold’ is the tomato that makes one unable to be a hybrid snob. I remember I did a “Splendid Table” episode last year, and Lynne [Rosetto Kasper] asked, “What are your desert island tomatoes?” so I have to repeat that.

Number 1 was ‘Sun Gold.’ But it’s versatile, because you can pick it pale orange, medium orange, intense orange, and you’ll get sharp tartness, you’ll get complete fullness—almost a tropical character—and candy sweet. And you can use them in pestos.

‘Black Cherry,’ which is essentially a cherry tomato—a small, half-ounce tomato that looks just like ‘Cherokee Purple’—is a ‘Cherokee Purple’ taste-alike. And a ripe bowl of ‘Black Cherry’ tomatoes looks like a bowl of Bing cherries, so chefs faces should light up when they think of the potential to use these to give not only incredible flavor but visual interest.

‘Egg Yolk’ has become one of my recent discoveries; I got that from the Seed Savers catalog. It’s a slightly larger cherry than ‘Sun Gold,’ and it’s a butter yellow, and I am creating a bit of an addiction for it here in Raleigh because many people are growing it alongside ‘Sun Gold’ or instead of it. So that’s one to look for.

Q. ‘Egg Yolk;’ that’s one I didn’t know.

So you have a driveway full of plants. Your wife is a very patient woman, because she probably can’t get the car out of the garage. [Laughter.]

A. No car has been in our garage in a long time, believe me. [Laughter.]

Q. That’s the mad chemist’s laboratory. So you have all these containers of various kinds; all these tomatoes. I assume you’re doing crosses as they are flowering. What in the world, if there are already 10,000-plus tomatoes in existence—what trait isn’t already out there? Are you breeding them down for that Dwarf Tomato Project size or what? What’s the grail?

A. My driveway is essentially a collection of many eight or 10 mini-projects, and one little mini-project is going back to the oldest ‘Cherokee Purple’ seed I could find, and it was actually 16 years old and only one generation removed from when Mr. Green [John D. Green of Tennessee] sent it to me. I wanted to get a sense of has it evolved over time as people have been seed-saving. When you see ‘Cherokee Purple’ in a market, does it look like what it used to when Mr. Green had it? So that’s a little project.

As far as the crosses we’re doing, we’ve done a really good job in the Dwarf Tomato Project of getting the big ones—the ‘Beefsteak’ types, the big, oblate different-colored ones. Where we’re turning to now is we’re trying to make some really delicious dwarf cherries, and we’re actually using ‘Sun Gold’ as a parent to see if we can get that ‘Sun Gold’ flavor into a dwarf-grower.

And paste and plum tomatoes—we want to see if we can get ‘Roma’ types on dwarf plants that have better flavor that the determinate ‘Roma,’ which produces like a machine, but you have to admit ‘Roma’ is not the first variety you think of when you think of running up to a vine and grabbing a tomato and taking a bite out of it.

Q. Um, no. But I did make a lot of sauce from it in my life, and I did can a lot of ‘Roma’ tomatoes. I did.

A. ‘Roma’ is a fantastic variety because when you process it in some way—roasting it, saucing it—the flavor comes out. Again, it’s interesting that some tomatoes show everything they’ve got raw, and some need a heat treatment or some type of processing to show you what their potential is.

It makes it fun, though right now I’m feeling the pressure of heat and humidity, and those containers need to be watered and regularly fed and troubleshooted—looking for the diseased foliage.

I’m glad I’m retired from my chemist corporate job, because my garden right now is a full-time job right now.

Q. What you said about one of the min-experiments out there in the driveway, about ‘Cherokee Purple’ and seeing if it’s still what you named ‘Cherokee Purple.’ That’s a really important point. I always say to people when I lecture about seed: “A ‘Brandywine’ isn’t a ‘Brandywine’ isn’t a ‘Brandywine.’” If you buy it from 10 different sources; it’s not widgets, folks. These are living things, this germplasm.

A. I love that, and if we treat them as living things we end of treating them with the respect that they actually deserve. Once a variety is gone, it doesn’t grow on trees; you can’t use a 3-D printer to recreate it. It’s gone. So I admire seed preservationists. The seed companies that offer non-hybrid seeds demand s much respect, because once you’ve got those varieties you really don’t have t go back to those companies. But there is that element of trust, and if people like ‘Brandywine,’ they’ll go back and try ‘Cherokee Purple,’ and that’s what keeps the heirloom companies in business—the diversity of what they offer.

Q. But would all ‘Cherokee Purple’ seed you could order be true to type?

A. That’s a fascinating topic we could spend a whole other episode on, because the seed Mr. Green sent me was a tomato captured at a point in time. My ability to grow that, and be careful with the seed-saving—if I can insure that I am not getting crossing—I  can maintain that point in time.

Going to farmers’ markets, and to restaurants, and seeing what people are selling as ‘Cherokee Purple,’ it is quite far removed from what Mr. Green sent me. I wouldn’t call is sloppy seed-saving, but inattentive seed-saving, or people not really understanding the mechanisms in the genetics. And maybe the bees have put a little pollen of something else out there are now ‘Cherokee Purple’ is a little smaller, or a little different inside, or lost a little of its flavor.

There are a few people—Carolyn Male, myself, and a few others—who have given ourselves the job of watching out for these varieties. We try to have a good memory, and a good documentation of what they were when they came to us. It’s important that our kids and our grandkids can have the pleasure of growing these without them being totally different and totally removed from what they’re supposed to be, because of no fault of anyone—but just because of genetics, and that it’s living tissue.

Q. I loved that “Epic Tomatoes” included some key recipes, like your roasted tomato sauce. Tell us how that works, and can any tomatoes work in it?

A. So what happens with people who grow lots of tomatoes is the glut. Since tomatoes are seasonally great, there is never enough until there is too much…and then soon there is never enough again. So salsa, and canning, and what we’ve found it the third great way is to combine seed-saving—because all my tomatoes have Sharpie marks on their shoulders to save seeds from.

So we cut them up into a bowl, any different colors, and put them in a roasting pan and add some sweet onion of you want, and garlic if you want, and drizzle olive oil, and add salt and pepper. But a low over—250 to 300 degrees F maybe, and just leave it there. Every hour or so set the time, and go in and stir it a few times. The tomatoes on the surface may char a little bit, and that will then reduce down and the flavors will then intensify.

Once it’s to a consistency that you like—some people like their sauces chunkier and thicker, some a little bit looser—then you’ve got a product you can can or freeze. I love to put that product in freezer bags and stuff the freezer with it, and be able to drag out a little taste of summer in winter.

Q. So any tomatoes, and it’s that simple. I think you’re right; the freezer bags are great. And you could probably make it into soup, even—very sweet and delicious.

A. And one of the things we found is that people are funny about food. Seeds and skins do not bother my wife and I.

Q. Me too. I never take them off.

A. We leave our skins on, which means you can do seed-saving and canning at the same time. Other people are very picky, and they don’t like that little rolled-up piece of something that may stick between their teeth.

There is something for every to find to do with tomatoes. We do treat them seasonally. We’ll eat them when they’re coming out of our garden, but once they’re done, we probably won’t eat a tomato again unless it’s canned or sun-dried from our garden. We treat them like strawberries.

Q. If it’s not tomato season, or something I’ve put up from my tomato season, I’m not eating tomatoes. I’m not buying them out of season.

People are starting to get fruits on their plants now. If I want to save seeds for next year—you just said you mark the ones to save seeds from with a Sharpie, and don’t eat them. How do you know which ones to mark, out there in that great driveway of yours? A. Great question, and I’m going to combine two answers: Number 1 is a great hint that I’ve found. As I’ve gone around the country speaking, people have different problems in different areas, but critters bedevil people everywhere.

One of the things that I’ve found is that if I pick tomatoes when they are well-blushing but not fully ripe yet, I can do two things. I can often avoid the cracking that happens with a lot of the heirlooms, because they’re not out there for that last thunderstorm when the skins are so tender. And when the tomatoes turn fully ripe on the vine, the smells then start attracting birds and raccoons and squirrels.

So that’s one thing: Pick your tomatoes about half to three-quarters ripe, and let them ripen indoors for a day or two, and they will taste fully as delicious as if you let them sit on the vine.

Now as far as seed-saving, because I don’t separate my plants too much, and I want to maintain their genetic integrity, I’m going after the first cluster of fruit and saving seed on those. Only because I’ve noticed that the bees in my garden don’t really travel so much until it gets a little bit warm, and maybe the third or fourth clusters of fruit are starting to form.

So I’ve got about a 99-plus percent chance, and I’ve proven that from saving varieties and testing them, of getting purity from early set fruit.

And here’s the other good news: The genes in every tomato—in every fruit on a single plant—are going to be identical. If your tomato is big or small, early or late, cracked or not—any of the seeds on any of those tomatoes will give the same results the next year, so you don’t have to aim for perfect.

Q. Now how did I not know that? I love it.

A. Not knowing that actually confounded seed companies early on, because they thought that if they went into the field and saved seeds from the earliest fruit that ripened, each year they’d be able to produce an earlier tomato. And then they got frustrated.

It was Alexander Livingston in 1870 who proved that you don’t look for a fruit on a plant, you look for a single early plant in a field of plants of the same variety.

Q. It makes total sense; if I had thought it through.

A. It’s fun to think it through.

Q. So you’re having fun over there?

A. Here’s how much fun I’m not having: Tonight Sue and I get to go to a tomato dinner at a local restaurant, where every course will be made of tomatoes, and my job is to show up and inform people between courses the history of the varieties they’re eating. So life is just really tough right now and I don’t know how I can do this. [Laughter.]

Q. I don’t know how you can stand it. And in that driveway of yours there are also eggplants and peppers –are those future passions of yours?

A. I dehybridize hybrid versions of eggplants and peppers to make non-hybrid versions that people can save seeds from. My last tip: I’ve found that pepper and eggplants grown in containers out-yield those grown in the ground 5 or 10 to 1. I’ve discovered that they really like hot roots, and when you plant them in the ground in clay soil, the roots never get hot enough for them to really crank out the fruit. So I will get 15 or 25 fruits off an eggplant or pepper in a 5-gallon grow bag; it’s amazing.

enter to win the ‘epic tomatoes’ book

I’LL BUY ONE lucky reader a copy of “Epic Tomatoes” by Craig LeHoullier. All you have to do to enter is type your answer to this question in the comments box at the very bottom of the page, after the last reader comment:

What’s your favorite tomato? (See, it’s an easy one this week.)

I’m a ‘Sun Gold’ lover as mentioned, and I love the grape-clustered hybrid ‘Juliet’ for making skins-on sauce, but it’s been going out of favor lately.

No answer, or feeling shy? Just say something like, “Count me in,” and I will–buyt a reply is even better. I’ll draw a random winner after entries close at midnight Sunday, July 17. Good luck to all.

prefer the podcast version of the show?

MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its seventh year in March 2016. In 2016, the show won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the July 11, 2016 show right here. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

(Purchases from Amazon affiliate links yield a small commission. Photos courtesy of Craig LeHoullier.)