I CALL THE phenomenon tomato troubles: the yellow-spotted foliage that falls off, or the plant that produces all those misshapen fruits. And yes, the attack of the hornworms, too, when you wake up to a lot of missing leaves one day. Or all of the above. August is a perfect time to check in with the tomato man himself, Craig LeHoullier, author of the book, “Epic Tomatoes” (affiliate link) and see what we can do even under such high summer pressures to bring in that delicious harvest.
Craig LeHoullier gardens and grows tomatoes in Hendersonville, North Carolina, the last couple of years after many years in Raleigh before that. He’s a proponent of the straw-bale gardening method, which he also wrote a book about. He’s an avid canner of his fresh produce and teaches an online Epic Tomatoes course with his friend and mine, Joe Lamp’l.
He shared his key strategies for tomato success, and explained the different tomato troubles you might be facing and what’s behind them. And learn the provenance of ‘Cherokee Purple,’ the beloved purple heirloom that Craig named, and was responsible for nudging into commerce (for which we all thank him). (Photo of Craig below by Shoe Heel Factory from Craig’s book. Tomatoes top of page by Joe Lamp’l)
Plus: Enter to win a copy of his book and some tomato seeds from Craig by commenting in the box near the bottom of the page.
Read along as you listen to the Aug. 8, 2022 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on Apple Podcasts (iTunes) or Spotify or Stitcher (and browse my archive of podcasts here).
high summer tomato tuneup, with craig lehoulllier
Margaret Roach: I’m glad to welcome you back to the show just in time to save us all [laughter]. Hi, Craig, how are you?
Craig LeHoullier: Hey, Margaret, how do I save myself? That’s the question.
Margaret: I know. Do you have the rescue squad on alert?
Craig: We have had a very, very unusual season here in Hendersonville. And so this is my third, and this was by far the most challenging, and I chalk it all up to mother nature who was just not as beneficent with me as she was the last two years.
Margaret: Right. The weather, the weather.
Margaret: So really selfishly, I wanted to talk to you to commiserate, as we just started to do, because I could tell on your Instagram that even with your expertise and all your years of experience growing tomatoes, ambitiously growing tomatoes, and breeding tomatoes and writing books about tomatoes, you’re still facing issues and even growing in straw bales.
Craig: Yeah. And there’s some mysteries that have popped up this year that I needed to investigate more fully, such as why are plants that are planted in virgin straw bales coming down with Fusarium wilt of all things [above; photo by Craig]. Because fusarium is typically something that builds up in garden soil over years. So was it seed-borne, is there in fact an insect vector? So lots of things…
Well, as you know, with every garden we have, there are mysteries to unwind and things to think about for the next year. But as you also can tell from my Instagram, there is no non-fun garden for the most part. You just roll with it and learn things and there’s always tomatoes to eat. So it’s been a really good year.
Margaret: Yeah. I loved on Instagram on your account, when you put a picture of your straw bales and what you just said, even though they were in this supposedly sterile medium or clean medium, not in soil with spores splashing up and so forth, that they were having trouble. And as a comment to that picture, to that post, one commenter said, “that picture looks a lot like my yard, yellow, wilty, and still throwing out great tomatoes. A year in the life.” And I thought that person, they know [laughter].
Craig: Well, one of the things I’ve found useful and comforting is to just share what’s happening and not gloss it over, and pretend that it’s not happening. I’ve been gardening 40 years. And I kind of have this thing that I think that in any 10-year period, maybe two gardens will be spectacular. Three or four gardens will be pretty good. And then you’re going to get those one, two, or three mystifying defeats for the most part, and almost always it’s due to weather.
And of course weather influences the onset of diseases and the presence of diseases and the different types of critters that come in. So it’s a very complex system with lots of variables that you and I and others get to have for our sandbox.
Margaret: Yeah. Are there some tactics that (like growing in straw bales, which is one that has generally been a big advantage for you, a tactical decision that has benefited your harvests and healthier plants and all that stuff)… Are there other things right now, when you start to see troubles, do you fastidiously remove discolored foliage? Do you know what I mean? Do you have other tactics that are the must things?
Craig: Yeah. So there’s the ideal and the must, and there is a direct dependency on your energy level that day and how many tomatoes you’ve already eaten. So what I find is the enthusiasm to get every spotted leaf and yellow leaf, etc., off the plant, is really a high priority early in the season. And then the days get into the 90s and you’ve already canned so many different quarts. And so you leave some of those leaves on and you may not feed as often as you wish.
And what happens is the plants say, “Well, thanks a lot, Craig,” [laughter] and they do what they do, which is the disease spreads quickly. So for things like Septoria leaf spot, which are the small brown spots that start on the lower leaves and it’s just all around us. Septoria affects all of the tomato plant family, even the weeds, the jimsonweeds and such. So it’s hard to avoid it.
And it’s hard to avoid early blight, because that’s in garden refuse that you may not clean up, and in plants all around us. That blows in. And I had the perfect storm this year, like many have in the country, of conditions that lead to that, which is lots of 3 or 4 or 5 o’clock thunderstorms, which means you have foliage that is staying wet all night. And those spores, as soon as it comes down, are floating around and getting onto the leaves.
So really, appropriate spacing, making sure your plants are stress-free, plenty of watering, plenty of feeding when they need it. And then just being really vigilant to remove those for first signs.
So Septoria and early blight will not kill a plant if you keep up with it. Fusarium is the bad one and bacterial wilt, but I don’t think we need to talk about that; that seems to be quite localized in different gardens, but it is also in the soil. Fusarium, or Verticillium maybe more in the West, are the ones that really get people because they attack through the roots. And once a plant gets it, you walk out, it’s wilting even though it’s well watered and then boom, it’s turning bright yellow. That plant may give you a few tomatoes, but it’s probably a goner. So that’s the one disease, I think, that leads to the most depression amongst tomato enthusiasts.
Margaret: Now you mentioned feeding. And so let’s just talk about when do you feed your plants, typically? Do you have a protocol of when you feed, because you’re growing, again, in these bales. If I’m growing in the ground, what would you be your recommended feeding interval?
Craig: Yeah, sure. So the amount I feed is really directly proportional to the amount that I’m having to water. And in the ground, I would say every two to three weeks, and then read the plants and see if they’re flowering. Lots of flowers out there, and the plant looks nice and lush and green, you’re on the right track. And use maybe a general all-purpose balanced fertilizer with NPK. Nitrogen, maybe a little more earlier in the season to get the vegetative growth going. Then a little bit more of the middle number, phosphorus. You can switch to a higher phosphorus content later in the season, which promotes blossoms.
But maybe two to three weeks. If you’re not watering so much, maybe once a month. In containers and straw bales, I’m going weekly, because the heat is forcing me to water daily. And that daily watering is leading to nutrients leaching out a little bit more quickly. So I find the weekly feeding is working perfectly. I’m seeing, before the disease hit, plenty of flowers, plenty of fruit set and all was going pretty well.
Margaret: And you’re using, it’s a diluted fertilizer of whichever brand you use, but a liquid feed we’re talking about.
Craig: Yeah, just the tablespoon per gallon, mix it up in a big container. I give each plant about a cup and a half a week and the plants love it. They really, really respond to it. And you really need to do that in straw bales because there’s no nutrients in the straw bale until you charge it up. Right?
Margaret: Yeah. And so, when you take off. So we start, then we eventually see some infected leaves and so forth. When you take off that debris, where do you put it in your garden? I mean, do you remove it to a distance? Do you know what I mean? Like what do you do with it? Yeah.
Craig: So I typically will fill up a one of those big black plastic shrubbery buckets, go around and just either snap it off or clip it off. And once I get that full, I go way back into my woods and just dump it in a pile back there. Because garden debris… People who don’t mulch, people who let their plants die off in the garden, they’re going to see early blight and Septoria [above; photo by Craig] more quickly because all of that debris may be harboring the spores. You get rain and it splashes that spore up onto your lower foliage.
So this is here is a testament to pretty much doing everything right, and still having things come in. But you know, my adage that goes along with this is since the 1850s, if you look in seed catalogs, we are being plagued by many of the same diseases that have been around for 170 years. And despite all of the research going on, we’re still finding very few ways to battle them.
So they’re a little bit like COVID [laughter]. Well, they’re very smart. And once you start hitting them with something or breeding varieties that are tolerant or resistant to one strain, what do they do? Well, we’re going to develop ourselves into another strain that’s going to escape it. So we’re really fighting the Darwin battle here, survival of the fittest, and diseases are all a part of that.
Margaret: I mean, you stake, I believe because you’re in straw bales. So your plants are up in the air.
Margaret: And so is that another tactic for sort of good garden hygiene, having them up in the air, not sprawling?
Craig: Well what staking does is it allows better air circulation, better sun exposure, and really less hiding places for critters, things like slugs and rats and squirrels to get under those plants. And also if the diseases are in the ground, you have no contact of the leaves with the ground to aid in the transference of those disease spores onto the plants.
The problem, of course, with staking, as the plants get tall, they’re indeterminate types. And one big windy thunderstorm will start the Leaning Tower of Pisa going on in your garden, right? I’ve actually had two plants go down. And as much as we’ve talked about these diseases, out of my, maybe 25 plants in straw bales, I’ve removed half a dozen. So there are still plenty that are doing really well. So I’m now starting to think about, did the roots of the plants go through the straw bales into the soil, and could it have picked up some disease that was harbored in the lawn from me gardening the last two years? This is where you have to put on your Sherlock Holmes cap.
And I do think about some of these diseases are absorbed into the seed coat, and even though you do fermentation, you dry your seeds nicely, you could have spores of things like Fusarium or early blight [below; photo by Craig] and Septoria sitting in the seed coats. And so they get into the plant and once the conditions become right, which is heat and humidity, it can trigger them. So I’ve got a lot… When I say I’ve got a lot of things to figure out, and you know me well, enough, Margaret. I’ve been doing this 40 years and every year I still feel like, my gosh, I don’t know anything about this. I have so much more I need to learn. And then I like to share it with everyone, because it’s no good to have knowledge unless you share it with your friends and other gardeners so we can all succeed together.
Margaret: Yeah. Well that was what you and Joe have been doing on the Epic Tomatoes course that people subscribe to that started at the beginning of the season and so forth.
Craig: Yeah. Well you bring up Joe. He and I have a combined 80 years of gardening experience. Joe will kill me if I say that, but it’s true, because he’s only 39. How can that be?
Margaret: I saw that on Instagram, too. That was so fun.
Craig: Oh gosh, it was fun. But his plants look a lot like my plants. So best-laid plans of mice, men, critters, hornworms and whatever, we’re going to have issues. That really should affect the numbers of plants people try to fit in, and this is kind of the war of attrition. If you only have three plants and they get hit by disease, you only harvest a few fruit. It’s a lot different. I have 60 plants this year. So when I lose four or six plants, I’m like, well, I can still can all of these tomatoes. It’s really not a tragedy. And of course not everybody can fit that many plants. But go for as many as you can is always my advice.
Margaret: You said, slugs. You have slugs? You’re having slugs? This is not something, I have to say up here in Zone 5, normally everybody asks me about slugs all the time, and I just don’t have… I mean, I see a slug now and again, but it’s never anything that I’ve lost a plant to of any kind. And I don’t see a lot of slug damage on things. And mostly because I think I have a lot of good helpers. I’m infested with every amphibian you can imagine [laughter], and a lot of reptiles too. And that’s great.
Margaret: Yeah. Lots of good slug-eaters over here.
Craig: My first year of the three I’ve dealt with them, and again, I think it’s the moisture and the wetness.
Craig: I just replanted some squash plants and some bean plants last night, because when I planted seeds, as soon as they germinated the next morning, the slugs would’ve eaten them all. So now I’ve actually sunk little cups of beer, not a great beer. I’m a stout drinker. This was kind of a mediocre IPA; I figure the slugs aren’t that fussy. But an hour after sinking those into the bales, where they were level each cup had about a dozen slugs.
Craig: Yes. It just insane.
Margaret: Oh my goodness.
Craig: And we had cucumbers and they were beautiful for a lot of the season, but all of a sudden it looked like roads were drawn on them because slugs all night had traveled over the surface and just nibbled. So yeah. We’ve had no hornworms. We’ve had only a few stink bugs. We’ve had no fruit worms. This has been strangely the year of the slug more than anything else. And it’s just mystifying. I never thought they would like to be on straw bales, because they’re rough and abrasive. They don’t mind at all.
Margaret: Yeah. So just let’s even if you’re not experiencing them, let’s just quickly… There’s some of those what I think of as like mechanical failures that aren’t diseases or pests, but that because of like dry-wet, dry-wet extremes or something, plants get stressed out. And things like you don’t get any flowers for a while, or the flowers don’t seem to get pollinated. You don’t get fruit set. Or you get these misshapen things. So, just a couple of examples. Do you know what I mean?
Craig: Yeah. So these are the three main, what we’re refer to as physiological effects. So they’re not the genetics of the plant so much. They are just the conditions that year, or they could be gardener operator error. And we’ll talk about that.
So the first is blossom end rot, and of course everybody has seen it. It happens a lot on sauce tomatoes like Romas where, oh, you’re so excited, you’ve got all these tomatoes set on the plant and then they all start developing a black sunken area on the bottom. And that is blossom end rot. That it really is brought on by an interruption in the normal calcium uptake of the plant, because the plant has become stressed. And typically it will mean the person’s been at work, or they’ve had their back turn and the sun is out and it’s 90. And the plant just visibly wilts. That stress level shown by the plant wilting is sufficient to interrupt the uptake of calcium, which creates the deficit, which leads to blossom end rot.
So even watering, drip irrigation, being super-vigilant. If you’ve got 90 to 95 degree days, go out at noon, give those plants an extra drink of water. And maybe, if you have a real problem with them in your zone, avoid some of the plum-shaped tomatoes and go maybe for more of the heart-shaped types, because they’re equally good for using in sauce, but they tend not to get blossom end rot as much as the ‘San Marzano’ and a ‘Roma.’ So just keep your eye on the watering. Mulch well.
There’s two that you mentioned. One of them is misshapen fruit, and catfacing is another word for it. The ugly heirloom is another. Yeah, well, that’s where it got that moniker. And that is partially genetically controlled because those of us who love to grow ‘Mortgage Lifter’ and ‘Cherokee Purple’ and the big flavorful tomatoes are just going to have to understand that those flowers are going to pollinate in somewhat cooler conditions sometimes, or a condition that is not perfect, and you’ll get a tomato that looks kind of funny.
And I’ve grown to love the ugly heirloom. I roll with it. You know, you cut the bad parts off. You can the rest. You eat, the rest. You save seeds from the rest. And the best way to minimize that actually is just to go with a rounder more medium-sized tomato, because those big ones are almost invariably going to have a few fruit that you could enter in the state fair for the ugly tomato contest.
And I think the third thing you mentioned, which is really the most of concern these days for gardeners the world over who are growing in warm areas, is the effect of extended periods of heat and humidity on growing tomatoes. And there’s two ways this is a problem. Under conditions where you’re 90 or above for extended periods of time, that pollen is really not going to move very well. The flowers aren’t going to pollinate very well, and you’ll have blossom drop.
In the course Joe and I are doing, a lot, ormost of the questions here, are coming in about poor fruit set because so many places have been hot as ovens. So either getting an electric toothbrush and just going at the base of the blossom cluster, when the flowers just opened and buzzing it for a few seconds, or flicking it with your finger. Setting up a shade cloth, so you can create a micro climate near those flowers that’s just a few degrees cooler.
The other thing is, keep your plant healthy. Don’t cut off all your suckers so that you have it flowering in several places on the plant all throughout the growing season, and you can overcome that.
The one that worries me the most is pollen die-off. When you get to temperatures 100, 105, 110, the pollen is actually going to be killed. And so again, we have to think about tactics to lower a microclimate. I think we’re going to see more high-tunnel growing, more construction of greenhouses, more indoor hydroponics to try to escape the heat.
So those are the three main things that plague gardeners that have nothing to do with the genetics, but just what the weather is doing to us at the moment.
Craig: Yeah. The “Ball Blue Book.” Yeah, I love it. It’s dog-eared, it’s coming apart. And I learned something interesting about canning and where we moved to Hendersonville. We’re at 2,500 feet now. And instead of doing a 45-minute hot water bath, we now have to do 55 minutes to compensate for the fact that the water boils at a different temperature. My jam was coming out really funny because it took me a while to figure that out. Or my yogurt, right. It affects a lot of things.
So yeah, I cut the tomatoes into pieces. When I get to about 25 pounds, then I get my seven one-quart jars out, wash them real well, tablespoon of lemon juice, teaspoon of salt, cold pack, hot water bath for 55 minutes. And I’ve had them last up to two years. I think in the last three years, we’ve canned 130 quarts and we’ve had two that it didn’t work out. And how we do it, when you go to use them you open it, you smell it. And if it smells like fresh tomatoes, you’re good. And if you have to pull your nose away, because it smells really, really bad, your seal didn’t work or the tomato had a rotten part. Don’t even think of saving that. That goes into the compost bin or down the drain.
There’s a lot of anxiety about home canning. I think once you’ve done it, and you understand the joy of reaching for a quart of homegrown tomatoes in the middle of winter and making a soup from it, it’s worth the effort. And once you do it enough, it’s really not even all that much effort. It’s just what you do for the next few hours, you know?
Margaret: So in the last few minutes, I wanted to ask you… I should have asked maybe at the beginning, because people might not know. You once named a tomato. You’ve named other tomatoes since, but you named a tomato that’s a very famous tomato. So tell us about that tomato. And how it came to you and so forth. So which tomato are we talking about?
Craig: Oh, well we’re talking about ‘Cherokee Purple,’ of course, which is my… And I have to say this, when Joe and I did our blind tasting ‘Cherokee Purple’ was included in the 15 that we tasted, and I had great anxiety. Because here’s a tomato I’ve loved for decades. And I wondered how would it come out when we tasted blind. And Joe and I both rated it. Blind tasted, randomized, we both rated it at the top of the class. So I’m not nervous anymore.
Craig: So in 1990, I was participating in a lot of seed swaps, and a fellow from Tennessee named John Green, who’s sadly since passed on, decided that I was the person he wanted to send this unnamed purple variety that he had. And he said it was given from the Cherokee Indians to the grandfather of a friend in the late 1800s.
So I couldn’t wait to grow it. I did, and it had that unique color. And so when I looked at it and thought, oh, I hope this tastes good. And we tasted it and it’s like, yeah, it tastes good. So I sent it to Jeff McCormack of Southern Exposure Seed Exchange. I named it ‘Cherokee Purple’ based on the info.
Jeff called me. He said, “That tomato is awful funny looking and awful ugly. I don’t think people will ever want to grow it, but I’m going to offer it in my catalog in 1993 with a strong caveat saying only for the adventurous.” And the rest is kind of history.
What I’ve learned since then, I had a few phone calls with JD before he passed on many, many years ago. He received it from a woman named Jean Greenlee, who lived in Rutledge, Tennessee. Jean received it from her grandfather. So the actual location that it seems to originate from was near Sevierville, a town called Rutledge, and it is a Cherokee nation area in the far Eastern part of Tennessee. The one thing I’m kicking myself, and I could still do this, is to make a little road trip out there and see if I can dig up a little bit more information about this.
Because well, it’s like typical genealogy. You know, our grandparents, we didn’t ask them all these questions we should have asked them before they passed on. So I’m in the same boat on lots of heirlooms. I am remiss and sad that I didn’t dig further. But when you’re young and you’re excited about collecting all these heirlooms, you’re just kind of looking ahead. I want to grow it and taste it and share it. And we don’t have the maturity when we’re young to think about what we should be doing in terms of obtaining information when we can.
Margaret: Well, we’re all glad that you introduced ‘Cherokee Purple.’ Even though Jeff McCormack thought it was ugly and for the adventurous [laughter], we’re glad it’s mainstream and everybody should grow it. So yeah.
Craig: Well what’s cool, Margaret is to understand how many adventurous growers there are now in the world.
Craig: Because the fact that tomato has caught on in a way was the sharp edge of the spirit to separate people from this “I just want to red tomato in my garden.” And now people are growing a rainbow of colors and tomatoes. That’s all good news.
Margaret: So Craig LeHoullier, I’m so glad that we got to talk at the high season of tomato troubles, as I say. And I hope I’ll talk to you sooner than later again. And thanks for making time today. Now go back out and do more weeding.
Craig: One second to say, anybody who gets that book, I will send them a signed book plate to the book, plus some seeds.
Margaret: Oh, that’s so sweet. Thank you. All right. Well, I’ll let you know who it is, and I’ll talk to you soon. Thanks.
connect with craig lehoullier
enter to win the ‘epic tomatoes’ book…and some seed
I’LL BUY A COPY of “Epic Tomatoes” by Craig LeHoullier for one lucky reader, and Craig will send along some of his own tomato seeds plus a signed bookplate, too. All you have to do to enter is answer this question in the comments box below:
What’s up in your tomato patch this summer (any troubles?), and how’s the harvest going (tell us where you are)?
No answer, or feeling shy? Just say something like “count me in” and I will, but a reply is even better. I’ll pick a random winner after entries close at midnight Tuesday, August 16, 2022. Good luck to all.
(Disclosure: As an Amazon Associate I earn from qualifying purchases.)
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 13th year in March 2022. 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 Aug. 8, 2022 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes/Apple Podcasts or Spotify or Stitcher (and browse my archive of podcasts here).