In the plant world, tomatoes, peppers, and eggplants are close relatives who share similar wants and needs, and I often group them together when describing how to tend the vegetable garden. For years I called this collective group the TEPs, until last season it dawned on me (quick thinker that I am) that I could rearrange the letters to spell PETs, which is much easier to remember. Hence the title of this page! This is a longer post (with lots of information!), so I’ve divided it into sections . . .
Meet the Family Solanaceae
Tomatoes, peppers, and eggplants are all members of the Solanaceae family, the agriculturally mighty Nightshade family. This wide-ranging group encompasses many economically important crops. In addition to tomatoes, peppers, and eggplants, the Solanaceae family encompasses other food staples, such as potatoes (suddenly the potato-leaf Brandywine tomato makes sense!), tomatillos, and gooseberries. Then there’s the ornamental plants, the money-maker member of which is the petunia. And then there’s the pharmacological species, most famously tobacco and belladonna. And since there are a good 2,700 species in the Nightshade family, you can see that the list goes on and on. All Nightshades are flowering plants, and many contain potent chemicals called alkaloids that function as both medicines and toxins.
What? Toxic Tomatoes?!
Yes, the Solanaceae plant family produces fascinating, sometimes useful, and sometimes deadly chemical compounds. These chemical substances, the alkaloids, interact with the human brain and nervous system, exerting an intense anticholinergic effect. Translation: These alkaloids have the power to dilate your pupils, speed up your heart, dry your sweat, disrupt your gut, and mess with your head. Nicotine is a famous representative of these Nightshade alkaloids, and atropine, an alkaloid from the belladonna plant, is well-known in medicine. Atropine is used in emergencies to speed up a falling heart rate. It has many other medical uses as well, but in larger doses, atropine is a poison.
The alkaloids in tomatoes, peppers, and eggplants are usually found in the green parts of the plants, such as the leaves and stems, and their alkaloids are generally present in too low of a concentration to be toxic to humans. There has been one report, however, of a person who died after drinking a tea made with tomato vine and leaves. Thus to be safe when eating your tomatoes, peppers, and eggplants, stick to the fruit. Don’t eat the green parts.
As an interesting side note, potatoes also contain an alkaloid that can be toxic, and it’s found in especially high concentrations in potato skins that have gone green. That’s why you’ll hear the advice to avoid potatoes with green skin and to store your potatoes in the dark (since sunlight is the culprit that turns potato skins green).
Getting a Good Start
Compared with most other garden vegetables, PETs have long growing periods. But they’re also frost sensitive, so here in Iowa, where the average last frost date doesn’t arrive until May, we give our plants a good head start indoors. Tomatoes need about 8 weeks to get to a foot in size, and peppers and eggplants need even longer. At the Pickle Creek greenhouse, we plant our first round of PET seeds in late February, and then we go on to do successive plantings all the way through March.
We follow this schedule because we sell transplants from late April to late June, and we like to have our plants at a certain optimal transplant size (about 3 sets of true leaves) at the time of the sale. We plant the ones we use in the Pickle Creek gardens in late March. I’ve met several people at markets who favor getting the biggest and oldest transplants possible, but we’ve learned over the years that the best indicator of a good PET seedling is a nice, thick stem and good, dark-green leaves. A healthy good-sized seedling will out produce a sad (or even a healthy but root-bound) big seedling every time. At least, that’s been our experience.
The great thing about tomatoes, peppers, and eggplants is that there’s hundreds of varieties, especially if you delve into the world of heirlooms, which I totally recommend you do. In my opinion, you can’t beat the taste of an heirloom, and there’s always a new fun variety to try. If you’re going to start with a transplant (which I recommend unless you have a greenhouse or just love to start your own seed), buy from a local grower at a farmers’ market or a food coop or even a small retail garden store. Buy from someone who loves their vegetables, has more than a few varieties under their growing belt (so to speak), and is more than happy to share their experience with you while helping you find the vegetables you can’t wait to eat already!
In the Garden
Tomatoes, peppers, and eggplants love heat and light, and they love sunny spots with warm soil best. I’ve come across books recommending that you preheat your garden soil before you plant your PETs, and I have a couple of friends who like to preheat their soil by covering the area with black or red plastic a couple of weeks before planting time. We’ve never tried preheating at our farm, however, so I can’t tell you how much good it might do for you. We’ve always been happy with our PET harvests, and I personally think the best thing you can do for your plants is focus on the nutrition in your soil.
You want to transplant your PETs into a rich soil with plenty of organic matter. If your soil is on the lean side, you can also add some fertilizer at planting time. Don’t overdo it with the fertilizer, however, or the roots may burn. I recommend finding a garden fertilizer that is specifically geared toward vegetables, meaning that it contains lots of micronutrients and not just nitrogen, phosphorous, and potassium (the infamous NPK of the plant fertilizer world). And speaking of nitrogen, you want to avoid fertilizers that are too high in nitrogen, or you’ll get a lot of leaves and few fruits. Again, your best bet is to go for fertilizer that’s specifically for vegetables. I’ll also add that organic fertilizer is always my fertilizer of choice (usually has better nutrients in it). And if all of this fertilizer stuff sounds tricky to you, then skip it and go straight for my all-time favorite soil hack: worm castings. For more details on the awesome powers of worm castings—otherwise known as worm crap—keep watching my blog (I’ve got a worm castings post in the works)!
When you transplant your PETs, bury them deep. Pinch off the bottom few leaves so you can bury the plants all the way up to the bushy leaves. When you’re planting indeterminate (vine) tomatoes, stake or cage them at the same time you put them into the ground so you can avoid disrupting the roots later on. Another thing I recommend when you’re first planting your PETs is to cut the bottom and top off a clear gallon milk jug to create a cylinder you can place around your plant. Anchor the jug firmly by screwing it down into the soil (so it won’t blow away), and then just leave the jug on the plant for the rest of the growing season. In the early days, the jug will act as a miniature greenhouse that helps heat and protect the plant. In the later days, the jug will act as a barrier to certain insects and also to any soil that might splash up onto the plant during a heavy rain. It’s best to keep soil off the stems and leaves of your PETs since the soil contains fungi that can infect the plants.
Another trick to keep soil from splashing up onto your plant, and also to help regulate water uptake by your plant (especially useful when your tomatoes are ripening), and also to save yourself from the massive headache of weeding, is to much well around your plant with straw, grass clippings, or whatever is your mulch of choice. We like to use organic straw that we grow on our farm. Before you mulch, however, cover the ground surrounding the plant with a layer of newspaper that is 5 sheets thick. The dark environment beneath these 5 sheets of newspaper will prevent the germination of any would-be weeds and will save you from a ton of weeding on down the road. These days on our farm, we use professional gardening paper that we lay down with a bed shaper pulled behind our tractor, but before we got the bed shaper we used this newspaper method for years, and for years we managed to avoid any kind of major weeding. When you first lay down the paper, have a hose ready so you can drench the paper with water to hold it in place until you can get the mulch down on top of it. It’s a little bit of extra work early in the season that will prevent a ton of work later in the season—totally worth it.
Water Water . . . Never?
In our gardens, we water our plants really well when we first transplant them into the ground, and then we water them a few times after that to make sure they get themselves well established. And then we try not to water the plants the whole rest of the season. This method is called dry farming, and in the long run, although sometimes watching the sky for that cloud and crossing your fingers for that rain can be a harrowing, nail-biting experience, it can make for much hardier plants capable of producing more flavorful fruits (especially tomatoes). The lack of irrigation coaxes the plant into concentrating its sugars in its fruits, which leads to tastier meals for you. So, assuming it’s a decent year for rain, leave the watering up to nature.
Of course, dry farming is not a good route to go in years or areas of severe drought (like the one we had a couple of years ago). A little stress is OK for a plant—a lot of stress, not so much. If your plants look like they could really, really use a drink, and if they’ve looked like that for a couple of days, go ahead and start irrigating! And if it’s a dry, rainless year that calls for irrigation, be sure to be regular and even with your watering, as doing so will help the plant produce the best fruits. Irregular watering (missing a week and trying to make up for it) leads to blossom end rot and cracking. Irrigation is no match for rain. You have to be good and regimented when it comes to irrigation.
The Dreaded Fungus
Soil-borne fungal disease tends to manifest as fruit rot (dark spots on fruits), leaf spot (dark spots on leaves), or blight (dying yellow and brown foliage). It usually shows up first on the lower part of the plant and slowly works its way up to the top. If it gets too out of hand, it will affect your production. So it’s worth taking a few measures to try to prevent soil-borne disease. As mentioned, simply keeping the soil off your plant will go a long way toward controlling these fungal infections. Another simple thing you can do is pinch off the diseased parts of the plant as soon as they start to look a little suspicious. For your tomato plants, once they are about 3 feet tall, you can routinely remove the leaves from the bottom foot of stem as an added preventative measure. You can also do your whole garden a favor and practice rotation. And then, of course, you can go back to your garden’s roots, literally, and focus on optimizing your soil. Make sure your plans have the right nutrition. If you have persistent disease or production issues, get a soil test from a lab that will give you micronutrient numbers and make input recommendations based on your test results. We use Kinsey Ag for our farm. You can also try spraying your garden weekly with compost tea (I would love to say more but that’s a post for a later date—keep watching the blog).
And There’s More!
Yes, there’s more that can be said about the PETs. I haven’t written a word about, say, insect pests or pruning your tomatoes. And I’ve said nothing about harvesting. When it comes to insect pests, as long as you use the gallon milk jug (especially around eggplant, which when not protected by the jug can be decimated by jumping flea beetles) and as long as you keep an eye out for hornworms (and pick those guys off your plants as soon as you lay eyes on them), you shouldn’t have too many problems. And as far as pruning your tomatoes go—in all honesty it’s always that item sitting on our to-do lists that we never quite get to doing. But we’ve never had a problem producing the amount of tomatoes we desire. And as far as harvesting goes—you’ll get the hang of it pretty fast once your fruits start ripening.
If you take away one message of this post, it’s this: Focus on your soil. Get your soil right so that nature can do its job, and the rest will fall into line. That’s the power of giving a natural ecological system what it wants. You feed it, and it will feed you.