Tomato growing guidelines

Planting and growing tips

By Renee Studebaker, based on a column she wrote for the Austin American-Statesman in 2011. Updated for 2021. 

In matters related to growing tomatoes, I’ve learned to never say “never” or “always,” especially given that I live and garden in Central Texas, where the summers are obscenely hot and the winters are extremely unpredictable. And there’s also the rain problem (never enough except for when there’s way too much all at once).

So given the variables, I don’t think I’ll ever get bored or complacent about tomato growing, because just when I start to think I’ve got it all figured out, I stumble onto some new bit of soil science or hear about a growing tip I’ve never tried before.

Here’s a list of commonly accepted guidelines for growing great tomatoes.

Seeds: Start seeds indoors under grow lights or in a greenhouse six to eight weeks before you intend to plant outside. Press the seeds into moistened seed-starting mix or a mix of seed-starter mix and compost. Yogurt cups or paper coffee cups work fine as pots; poke several holes in the bottom for drainage. Keep seed pots moist and warm (between 70 and 80 degrees) until seeds germinate. A seed heating mat helps, or set your pots under a heat lamp. 

Seedlings: After the first set of true leaves pops out, begin light weekly feedings with liquid seaweed and/or fish emulsion. To prevent leggy seedlings, keep seedlings under grow lights,  in a cool area, ideally between 62 and 70  degrees. Keep the grow lights close, about 2 inches above plants.

Transplants: To promote a vigorous root system and get your young transplants off to a good start, pinch off the lower leaves and plant them deep. If your transplant is long and leggy, dig a trench and lay the plant on its side so that only about 3 or 4 inches of the main stem and its leaves are above ground. If you’ve got a sunny patio or balcony, you can grow tomatoes in an EarthBox or something comparable (www.earthbox.com), or simply try a large pot or bucket.

Soil prep and amendments: Loosen the top 6-8 inches of soil with a cultivating or digging fork and then gently work plant-based compost or leaf mold (aged leaf mulch) into the top two or three inches of your soil. This addition will feed soil microbes and improve the tilth of your garden soil. You can improve the fertility of your soil with rock powders or animal based fertilizers, but it’s easy to overdo amendments, so it’s best to get your soil tested before adding anything other than a small amount of nitrogen. Rock powder amendments include: rock phosphate (for phosphorus), greensand (for potassium and trace minerals) and decomposed granite or sand (for trace minerals) Animal-based amendment options include earthworm castings or composted manure (for minerals and nitrates). 

If you’re growing in containers and want to keep it simple, try mixing compost with a good quality potting soil, then once a week, add a bit of slow-release organic fertilizer (granular or liquid).

If you’re growing in a raised bed, simply add a good quality growing mix. Green Corn Project uses GeoGrowers garden soils, but there are a number of good bagged growing mixes available in area nurseries that are recommended for organic raised bed gardening. 

When to plant: March 5 is the average last freeze date for our area, and that’s when most gardeners start planting their tomato transplants. If you’re an eager overachiever, you can try planting a couple of weeks earlier in cages and stretch plastic wrap or row cover around the entire cage to keep the plants warmer when nighttime temps drop into the 40s. Be sure to remove the wrap when temperatures are regularly in the 80s during the day and 50 or warmer at night. 

Pruning: Sorting out all the pruning tips can drive a gardener crazy: Prune only the suckers; prune the suckers and stems to two or three productive stems; or don’t prune at all. Or, if you’re into extremes, prune all but three leaves. I’ve tried pruning a little and pruning a lot, but have for some time been in the no-pruning camp, mainly because I’ve never found the payoff (larger tomatoes) to be worth the effort. The only reason I can see for pruning is if you’re gardening in a small space and need to keep plant size in check. But in that case, I think choosing a determinate or compact tomato variety is a better option.

Fungus and disease: Many experts say you should avoid watering from above because it makes plants more vulnerable to fungal diseases. But others say not to worry about it, because that’s what plants are used to (aka the how-can-rain-be-wrong argument). I generally hand water or use soaker hoses, but I also sometimes use overhead sprinklers in the early morning hours. Other common suggestions that have made a positive difference in my garden: Trim off lower leaves to avoid the splash of soil-borne pathogens. Spread mulch around plants after they are well established to further reduce splashing. Space tomato plants at least 2 feet apart to allow for better air circulation. Choose disease resistant plant varieties. Spray every other week with liquid seaweed. Treat soil every couple of years with beneficial nematodes. And finally, feed your beneficial soil microbes with leaf mold and compost so they can do their part to help keep your plants healthy.

Insects: Many experts recommend rotating plants on a three- or four-year cycle to keep bad bugs on the run. But that’s a hard thing to pull off in many home gardens, mine included. I rotate as much as I can, but it’s usually closer to a two-year cycle. Either way, be sure to focus on maintaining a healthy population of beneficial soil microbes and beneficial insects. A diverse variety of herbs and flowers helps attract beneficial insects. In addition, try to check plants regularly to get the jump on bad bug breakouts.

Get in the habit of walking around your garden and inspecting your plants. That’s the best way to spot early signs of fungus or disease, as well as baby hornworms, stinkbugs and leaf-footed bugs. If you have a pesticide-free garden, you’ll have lots of bugs on your plants, but that’s actually a good thing, because many of them will be beneficial bugs. Get to know the good bugs from the bad bugs before you start squishing and spraying.

No matter what growing method you choose, you’re probably going to have some yellowing and browning caused by various diseases, some damage caused by bad bugs, and some fruit loss due to thieving critters. But come harvest time, you should also have enough tasty tomatoes to make it all worthwhile.

Tips for fighting common tomato pests

By Renee Studebaker. Based on a column written in 2009 for the Austin American-Statesman. Updated for 2021. 

There are two simple truths about homegrown tomatoes: First, nothing tastes better (OK, maybe chocolate). And second, nothing makes a gardener madder than losing prize fruits to tomato-chomping bugs and thieving critters.

Which means said gardener will do just about anything to protect precious plants from tomato pests: stink bugs, leaf-footed bugs, spider mites, tomato hornworms and squirrels.

With the possible exception of hornworms (they’re big, slow and fairly easy to hand-pick), tomato pests are among the hardest pests to deal with organically. I’ve got a few methods I rely on to keep the bad bugs and critters at bay in my garden, but I’m always on the lookout for better solutions, so I consulted with gardening experts Skip Richter, Jeff Ferris, and Dick Pierce to find out how they deal with tomato pests. 

Ferris is host of KLBJ radio’s “Gardening Naturally” organic gardening talk show. He’s also a staff horticulturist at The Natural Gardener. He is a certified permaculture designer and has been teaching  in Austin Community College’s Landscape and Horticulture program since 2008.

Robert “Skip” Richter is the Texas A&M AgriLife Extension Horticulture Agent for Brazos County and formerly AgriLife director for Travis County. (For more tomato tips from Skip, check out his column in The Eagle)

Dick Pierce is one of Austin’s leading Permaculture teachers, a long-term advocate for local food and community-building, and a co-founder of the Citizen Gardener Program.

Q: For stink bugs and leaf-footed bugs, I handpick, suck them up with a hand-vacuum and sometimes spray with a weak solution of orange oil. What else works?

Richter: That’s a tough one. Two bricks work well! But seriously, there is not a low-tox, natural control that I have found to be effective against these pests. I think we need to get some gardeners to experiment with stuff like the oil you mentioned (careful: not too strong or it will burn plants), and perhaps some of the new plant-based oils such as in Green Light’s Bioganic oils (combinations of thyme, clove and other oils) as repellency products.

Kaolin clay may also work to repel. (However,) I have no data that shows that this would work, or if so, how often it would need to be used. Finally, some folks report success with planting things the stink bugs like better to lure them away and then controlling them on the attractant crop. Examples: sunflowers, black-eyed peas, cardoon blooms, bread poppy seed heads.

Pierce: I like your general, organic approach — also fits with permaculture: Use natural biological remedies first, such as parasitic wasps and flies that use worms as food for their eggs/larvae. Then use mechanicals — pick ’em off by hand. Then organic preparations like orange oil.

Next, let the bugs have 10 to 30 percent of your crop or tolerate a tasteless blemish. Advice for next planting is never in the same place twice. Rotate them around to far corners of your garden so you’ve moved next season’s crop away from this season’s bugs and their larvae in the ground. 

For planting new tomatoes in the fall, really pay attention to the 50-60 day varieties and notice that many bugs don’t have a fall cycle.

Ferris: For the bugs, an organic product is Neem oil, an IGR (Insect Growth Regulator). Keeps the insects from moving to their next stage of growth, meaning no more eggs. The nice thing about Neem is it works on stink bugs and leaf-footed bugs. As always, it’s best used when you first see them. You want to gain control before they are laying eggs. This is a product best applied a couple of times over a two-week period. You get the adults, then the hatchlings.

But personally, picking is what I think works best. You cannot get a more organic or garden-safe control than using the tools at the end of your arms. Get a bucket, put in a tablespoon of dish soap, fill with about a gallon of water. Throw the bugs into the bucket. Keeps them from flying away, kills them quickly. Best very early in the morning. Bugs are like people; they don’t move very quickly before they have had their morning coffee and are easier to grab.

I’m not a fan of orange oil. It has its place, and it works really well when used carefully. But in our hot weather, the oil has to be used carefully; it can burn the plant leaf if it’s too strong. And some plants are more delicate than others.

Q: For hornworms, I mostly just check regularly for them and handpick. Wasps and hornets snag some of them. Also birds. And occasionally I see the little white eggs on the back of a hornworm that let me know he’s been visited by a parasitic fly. What am I leaving out?

Richter: That covers it. If one goes out daily or so to check plants, they won’t do much damage before being discovered. Call a neighborhood child to your place, drop a hornworm on the sidewalk and step on it, and they’ll think it is so cool you won’t have to do any more hand-picking yourself. Think of it as “importing natural enemies of the hornworms.”

Ferris: For hornworms (and other caterpillars), a good organic is Bt (Bacillus thuringiensis). When eaten by the ‘pillar, it causes it to stop eating, and very rapidly. They then starve to death. Safe to use when used correctly, low or no impact on other good insects, and works better the younger the ‘pillar is when it eats it. DO NOT use anywhere around your butterfly garden, only on your veggies, and even then, be aware you make a trade-off — you have to have caterpillars if you want butterflies.

Q: To attract the beneficial bugs that eat the bad bugs, I like to plant a variety of flowers and herbs, including yarrow, dill, borage, Thai basil, and fennel.  What other plants would you recommend to help keep beneficial bugs happy in the garden?

Richter: Those you mentioned are fine. I would add chives and cilantro (let them bloom), thyme and tropical or Mexican milkweed (which attracts a yellow aphid that doesn’t plague our other garden plants but will attract lots of lady beetles, lacewings, syrphid flies and parasitic wasps, which will then patrol our other plants).

Ferris: I like your plant list, but I would add marigolds. The variety “French Vanilla” (Tagetes erecta “French Vanilla”) smells OK, is kinda boring looking (a beige flower), but it produces substances in its roots that nematodes don’t like. And I would add basil … next to the tomatoes. Basil is a good companion plant for tomatoes; many would say it improves the flavor of the tomatoes. Let some go to seed — it will draw a lot of bees.

Q: For squirrels, I’ve found nothing that works better than bird netting, with edges pinned down so they can’t get under. What do you recommend to keep squirrels and other critters from stealing or ruining tomatoes?

Richter: Make dumplings. But seriously, I don’t know any other good options. I wonder if the ScareCrow motion-activated sprinklers would work? I know they are great for keeping cats and dogs out.

Ferris: I don’t have a squirrel issue — at least not yet. Bird netting is a pain, but I guess that’s a personal choice depending on how bad you want tomatoes. I would consider plastic or inflatable snakes around the tomato cages. Also, I really recommend a bird bath near the tomatoes, and you must keep it full during hot weather. Mockingbirds (and other birds) are notorious for poking holes in tomatoes. They aren’t after the flesh. They’re looking for moisture.

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