10 Tips for Growing Tomatoes

Why You Should Grow Tomatoes

Here’s a secret. I’d grow a garden just to grow my own tomatoes. Who can blame me? Is there anything better than a fully ripe tomato eaten while it’s still warm from the garden?

Tomatoes annually rank as North America’s #1 home garden crop. No vegetable (technically a fruit) has received more attention from plant breeders and seed savers, which gives us lots of varieties to choose from.

However, you need to read these tips on growing tomatoes to start your plants off right and avoid problems before they happen.

10 Tips for Growing Tomatoes

1. Choose the Right Tomato for Your Climate

There are many varieties of tomatoes. Consider these four main factors:

1. Climate and the length of your growing season. If you live in a northern climate, your tomatoes may not even have time to turn red. Look for varieties that are for cool climate/short season such as “Early Girl” (matures only 50 days after planting); most other short-season varieties will be cherry tomatoes. There are also tomato varieties that are heat-tolerant and best for hot Southern gardens such as “Heatmaster” and “Arkansas Traveler.’ See Bonnie Plants’ Tomato Chooser to find the variety with the traits that fit what you’re looking for.
    
2. Type of tomato: Do you want tomatoes for pasta and sauce? Or, a great slicer? Or bite-sized? Romas, plum, or ‘paste’ tomatoes are excellent for cooking because they contain plenty of flesh for sauces. Beefsteaks are chunky and juicy so great in salads and on burger. Cherry tomatoes have the sweetest taste and wonderful for snacks and children. See our post on growing cherry tomatoes!
    
3. Growing habits: Tomatoes are either determinate or indeterminate. Learn the difference and remember that indetermines must be staked early to avoid disease.
   • Determinate or “bush” varietes stop growing at about 3 feet tall. These compact plants fruit all at once, and tend to be good for making sauce or canning (when you’d want a lot of tomatoes all at once). Most bush tomataoes like a cage and some are well suited to pots.
   • Indeterminate varieties will keep on producing fruit throughout the season until the plant is killed by frost. These plants get quite large and will need definitely some kind of tall supports (at least 5 feet) so stake, or cage  plants early. If fruit sprawls across the ground, they will be prone to disease. Indeterminates are great for salads and sandwiches.
      
4. Disease-resistance: Tomato names are usually followed by capital letters that stand for resistance to certain diseases. Pay attention to these letters, especially if you have had one of these diseases in your climate before. If you live in temperate climate with lots of moisture, consider blight-resistant tomatoes. Hybrid examples are ‘Iron Lady,’ ‘Defiant’, ‘Mountain Magic,’ ‘Mountain Merit’ and ‘Jasper.’ Heirloom examples are ‘Lemon Drop’, ‘Matt’s Wild Cherry’, and ‘Mr. Stripey’ (also called Tigerella). ‘Jasper’, a tasty red cherry. See our article on avoiding blight with the right tomato.

Read more about choosing the right tomato variety.

2. Give Tomatoes Enough Light!

Tomates LOVE the Sun. Many beginner gardeners start their tomatoes from small plants purchased through an online catalog or at a garden center.

If you are planting from seeds

If you are seeding yourself, it is critical to provide strong, direct light. (Note: If it’s after your frost date, it’s too late to sow tomatoes from seed.) 

For seeding and young seedlings, northern gardeners should use grow lights 14 to 18 hours a day to provide an early boost and promote upright growth. Without enough light, your plants will be spindley and not have a good start to life. Learn how to start tomatoes from seed. 

Planting seedlings or transplants in the ground

If your seedlings were grown indoors or in a greenhouse, do not just go outside and set them in the cool ground. Outdoor tomatoes will first need acclimatizing to outside conditions to avoid cold shock.

If the plants have been inside a greenhouse, harden them off over a period of two weeks. Begin by leaving plants outside for just a couple of hours a day then gradually increase the length of time they spend outside, avoiding windy days. Bring plants under cover if temperatures threaten to drop below 40 degrees Fahrenheit. Plant outside only after all danger of frost has passed.

When planting in the ground, choose your sunniest spot with at least 7 hours of direct sunshine a day. For tomatoes, sunshine is like water and they’ll soak it up and produce more fruit! Also, make sure your tomatoes aren’t too crowded so the sunshine can reach their lower leaves. Plant seedlings (small plant) 30 to 48 inches apart, with rows set 48 inches apart.

3. Preheat Garden Soil and Beef It Up!

Be careful not to plant tomatoes in the ground too soon. They are heat-lovers. Your soil temperature must be consistently over 60 to 65 degrees Fahrenheit. Warm the soil with plastic a couple of weeks before you intend to plant. If it’s still iffy, protect seedlings from the cold with sheets or row covers.

Tomatoes thrive in rich, well-draining, slightly acidic soil with a pH of 6.5 to 6.8. Two weeks before planting your tomato plants outdoors, beef up that soil! Dig into soil about 1 foot deep and mix in aged manure or compost. 

4. Plant Tomatoes Deeply

When you do plant tomatoes, plant a little deeper than they come in the pot, all the way up to the top few leaves! Tomatoes root along their stems so this trip helps them develop stronger roots. 

With leggy transplants, dig a trench and lay the stem sideways, bending gently upward. Snip or pinch off the lower branches and cover with soil up to the first set of leaves. This extra root growth will produce a stronger, more robust plant.

See more on planting tomatoes.

5. Mulching Tomato Plants

Don’t forget to add a blanket of mulch! It helps to conserve moisture (tomatoes love their water!) and keeps soil-borne disease spores from being splashed up onto the plants. There are many good mulches to choose from—shredded pine bark, straw, shredded leaves, grass clippings, composted leaves, or even a thick layer of newspaper. Oddly enough, red plastic has been found to increase fruiting by 12 to 20%. Read our Mulching Guide for more information.

6. Remove Bottom Leaves

After your tomato plants reach about 3 feet tall, remove the oldest leaves from the bottom foot of the stem. This reduces fungus problems because the leaves are usually shaded by the rest of the plant and near the soil. Spraying weekly with compost tea also seems to help prevent fungal disease. Learn more about compost tea.

7. Pruning Tomato Plants

To pinch or not to pinch, that is the question. Most gardeners pinch and remove some of the suckers that form between the main stalk and the side branches during the early growth of their plants (the crotch joint). They won’t bear fruit and will take energy away from the rest of the plant.

Note: You definitely do not want to prune determinate varieties or you will have only a few fruit clusters. Since determinates bear fruit only on the ends of their branches, never clip them off, or you won’t get any fruit at all!

But just how much should you prune them, if at all? Pruned plants bear earlier and have larger tomatoes, but they also have fewer tomatoes. Overpruning can cause sunscald—a yellow sunburned patch that eventually blisters. Unpruned plants yield about twice as much fruit as pruned ones do, but it will take longer for the fruit to ripen. Pruning also affects flavor. The more foliage a plant has, the more photosynthesis is taking place, which produces more sugars in the fruit. The excess foliage shades the fruit and insulates it from summer heat, making it ripen more slowly and improving the taste.

Of course, if the foliage on your plants is so thick that no fresh air can reach the center of the plant, then by all means, pinch off a few suckers. If your indeterminates are reaching for the stars, you can top them above the highest blossoms to keep them in bounds and encourage green fruit to ripen.

8. Watering Tomato Plants: How Much is Enough?

Juicy tomato plants need 1 to 2 inches of water per week.

Water deeply. A soaker hose is an efficient solution; just position the hose in the garden and pile mulch up and over the hose.

And don’t forget to water consistently. Uneven watering can set the stage for blossom-end rot and may also cause fruits to crack open. Stressed plants remove calcium from the fruit and send it to the shoots to keep the plant growing. Along with uneven moisture, excessive nitrogen and high soil acidity contribute to blossom-end rot.

9. Feeding Tomato Plants

Most gardeners have a secret or two up their sleeves. One man I know treats his plants to crushed eggshells in the planting hole, another uses a handful of bonemeal, and someone else swears by a pinch of Epsom salts. If you must fertilize, side-dress the plants with compost or a dose of liquid seaweed or fish emulsion.

Stay away from high nitrogen fertilizers unless your plants have yellow leaves. Too much nitrogen will cause lush foliage growth but give you little or no fruit. If the leaves on your plant are purple, they are calling for more phosphorus. This is the most important nutrient for fruit production.

Some gardeners like to feed their tomatoes compost tea to keep heavy-feeding tomato plants happy. Soak one part organic compost in one part water, let sit for 24 hours, filter the “tea,” and use to nourish plants. 

10. Try Companion Planting

Here at the Almanac, we practically invented modern companion planting, following in the footsteps of Native American growing techniques.

We’ve always found that tomatoes seem to thrive when planted with basil, just as they do in the kitchen! Basil and marigolds act as a natural insect repellent when planted amongst tomatoes, helping to ward off whitefly.

Borage attracts bees and tiny pest-eating wasps, making it a great companion for tomatoes. 

See our full Companion Planting Guide as well as a chart of popular companion crops including tomato.

We believe these 10 tips cover the best advice for starting tomatoes. If all this advice seems daunting, take heart: Tomatoes are really one of the easiest vegetables to grow, and even the worst home-grown tomato tastes better than a store-bought one.

As you grow your tomatoes, you may run into some problems. Tomatoes will attract pest and disease but if you keep your eye out for them, you can avoid many problems. Learn more about tomato diseases and disorders. And also see how to think ahead and troubleshoot tomato problems.

Here is the Almanac’s complete Tomato Growing Guide for everything you need to known about planting, growing, and harvesting tomatoes!