How To Grow And Care For Tomatoes

We're all for locally grown foods, and you can't get much more local than growing tomatoes right outside your door—what's tastier than reaching out and grabbing the perfect garnish or key ingredient for your favorite summer recipe? Even if you're short on space, a tiny, sunny patch of earth can become a productive planting bed for tomatoes.

This warm-season vegetable/fruit should be added to the garden after all danger of frost has passed and when nighttime temperatures stay above 50°F. Because hot summers can prevent the plants from setting fruit, tomatoes are usually grown as a fall or winter crop in Zone 10.

Tomato plants (Solanum lycopersicum) are divided into two types: determinate and indeterminate. Determinate tomato plants are more compact, require less staking, and produce their crop all at once—a real advantage for canning purposes. Most grow to three or four feet tall, although some patio varieties top out at 12 inches. Indeterminate tomato plants, which tend to vine, require trellising or cages, continue to grow, and produce fruit until the first frost. As for the fruits, they come in a wide variety of shapes: cherry, grape, pear-shaped, heart-shaped, globe or slicer, big lobed beefsteaks, and plum. Colors range from deep purple to red to pale green, ensuring there's always a new variety you can experiment with in the garden.

The stems and compound leaves of tomato plants are very hairy and have a distinctive musky scent. A reminder: Keep pets and small children away from the plants as the stems, leaves, and roots are toxic to animals and to people, though some experts say adding a few tomato leaves into your sauce won't cause harm.

Plant Attributes

Tomato Care

Tomato plants happily grow in sun-drenched, warm soil with good drainage. Provide consistent moisture and a side dressing of tomato fertilizer for the best-looking fruit. Most varieties naturally collapse and grow along the ground unless you provide good support in the form of a cage, trellis, or stake. Indeterminate varieties grow endlessly, sometimes reaching 10 feet tall, and should be planted three feet apart to give them plenty of space.

The more compact determinate varieties can be planted two feet apart. Make sure you choose the right variety for the space you have available, especially if you plan to grow yours in a container. Tomatoes should be planted deep in fertile, well-drained soil. You can bury up to two-thirds of the stem, removing any leaves that would be below ground. The stem will sprout new roots that result in a stronger plant.

Light

Plant your tomatoes in full sun where they can receive at least six to eight hours of direct sunlight a day. Without adequate sunlight, you'll have fewer, smaller, and slower-to-ripen tomatoes. If your garden falls a bit short on sun exposure, choose varieties that bear smaller fruits, like cherry tomatoes. They won't be as prolific, but they should still produce fruit with three or four hours of direct sun daily.

Soil

Tomato plants perform best in mildly acidic, rich, and moderately moist soil. They like loamy (a mixture of clay, silt, and sand) soils, but they can grow in average garden soil as long as the soil is well-drained. They have been known to grow in clay but are not likely to thrive in heavy clay soils, so add plenty of organic matter to improve drainage. Mix in three or four inches of compost when you plant to improve drainage in clay soil or help retain moisture in sandy soil. Even in loamy soils, compost will provide much-appreciated nutrients to the plants and help them better produce during the harvest.

Have your soil tested before the growing season begins and add the recommended amendments to improve your soil's fertility. It is especially important to add lime if your soil is too acidic.

Water

Because tomatoes do best with consistent moisture, add two or three inches of bark mulch, straw, or shredded leaves around your plants. In the absence of rainfall, water tomatoes regularly, aiming for an inch of moisture per week and even more than that during hot, dry weather. Stick your finger in the dirt, and water if the top inch of the soil feels dry. Regular watering will help prevent your tomatoes from cracking, splitting, or developing blossom-end rot, which we discuss in more detail below. Tomato plants are susceptible to fungal diseases, so be careful not to get the foliage wet when watering.

Temperature and Humidity

Tomatoes are a warm-season fruit that grows slowly in cold soil and won't set fruit, or begin to grow berry-sized buds, if nighttime temperatures are below 55ºF. Don't plant until after the last frost of the season has passed, but at the same time, it's best to get your tomatoes in the ground early if you live in the South. The plants thrive when it is 70ºF to 80ºF during the day. Hot days above 85ºF, especially in high humidity, can prevent fruit from setting, often putting your harvest on pause until temperatures drop again.

If your soil temperature is under 60ºF, you can still plant early to beat the heat. Cover the soil around your plants with clear plastic so that the sun warms the soil. Remove the plastic and replace it with mulch once temperatures rise.

Gardeners in the Coastal South (USDA Zone 9) can plant one tomato crop in late winter for an early summer harvest and one crop in late summer for a fall harvest. In the Tropical South, like in Miami, tomatoes are often grown as a fall and winter crop.

Fertilizer

Tomatoes are heavy feeders that require lots of nutrients and benefit from fertilization. The best approach is to have your soil tested for recommendations specific to your garden. If you don't get your soil tested, choose a fertilizer formulated for tomatoes and other vegetables. These fertilizers have a lower nitrogen level, as too much nitrogen causes plants to produce lots of leafy, green growth instead of fruit. Commercial tomato fertilizers usually contain calcium to help prevent blossom-end rot, an issue caused by a calcium deficiency in the fruit.

Fertilize when first transplanting your tomatoes, mixing the fertilizer well into the soil according to the directions on the label. When the first fruits appear, side-dress the plants, or place additional nutrients near the plants, with more fertilizer (usually two to three tablespoons per plant). Some gardeners continue fertilizing every four to six weeks during the growing season, but this is weather-dependent—don't fertilize your plants during a heat wave.

Types of Tomatoes

When deciding which tomatoes to get, you can choose from hybrids or heirlooms in a rainbow of colors—red, pink, black, orange, or yellow. For classic reds, try 'Big Boy', 'Better Boy', and 'Celebrity'. For pinks, pick 'Arkansas Traveler', 'Pink Girl', and 'Watermelon Beefsteak'. Black selections offer some of the most flavorful tomatoes. Try 'Black Krim' or 'Cherokee Purple'. Orange ones such as 'Persimmon' and 'Kellogg's Breakfast' have fruity flavors, while yellows such as 'Taxi' and 'Lemon Boy' are sweet. Here are some of the most popular varieties classified by the type of fruit:

• Globe or slicer tomatoes: These uniform, spherical tomatoes look most like what you'll find in the grocery store. Cut them into wedges for your salads or slices for your tomato sandwiches. Color can range from pink to deep red, with the occasional yellow or green variety thrown in. Popular cultivars include 'Better Boy', 'Celebrity', 'Early Girl', 'Arkansas Traveler', and 'Green Zebra'. 'Celebrity' is semi-determinate, growing to three or four feet but continuing to produce fruit throughout the season. The determinate version of 'Early Girl' is labeled 'Bush Early Girl'. For compact slicer tomato plants that are perfect in your containers, reference seed catalogs.
• Beefsteak tomatoes: Huge, juicy, intensely flavored, and often lobed, these tomatoes are a prime choice for topping your burger. Common varieties grown in the home garden include 'Big Boy', 'Mortgage Lifter', 'Brandywine', 'Cherokee Purple', 'Kellogg's Breakfast', 'Black Krim', and 'German Johnson'. Most are indeterminate, but some companies sell seeds labeled 'Determinate Beefsteak'.
• Plum tomatoes: These meaty, oval-shaped tomatoes are classically used for canning and making sauces. Classic varieties include 'Amish Paste', 'Roma', and 'San Marzano'. 'Roma' is a determinate variety.
• Cherry tomatoes: These petite tomatoes are great for snacking or salads. Many are round, but you can also find grape-shaped and pear-shaped varieties. Examples include 'Sun Gold', 'Tiny Tim', 'Sweet Million', 'Black Cherry', and 'Yellow Pear'. 'Tiny Tim' is determinate, topping out at 12 to 18 inches, and well-suited to growing in a pot. 'Little Bing' is another compact variety that grows to 24 inches.
  

New to many gardeners are grafted tomatoes, which are created when one plant is cut and joined to a different one with vigorous rootstock. Grafting offers improved yields and disease resistance. It can be a good choice if space is limited and you need maximum production for each plant. Some heirloom tomatoes, for example, are not as productive as new hybrids, but if you love their flavors and want a bigger yield, you can try a grafted heirloom for the best of both worlds. The benefits of grafting come at a price, however—grafted tomato plants can be more expensive than other growing options.

Pruning

While pruning tomato plants isn't necessary, it can increase airflow, keep plants manageable, and improve the fruit produced by the plant. Pruning has been known to speed up the ripening process and can result in larger tomatoes, depending on the variety and selection. It is important to prune only indeterminate varieties of tomato plants. Indeterminate tomatoes continue growing all season and allow for pruning, while determinate plants' (also known as "bush" tomatoes) growth eventually stops and does not continue all season and would be hindered by pruning. Small patio varieties should not be pruned except to remove diseased or damaged stems.

Most importantly, stake or remove low-hanging stems trailing on or near the ground. With indeterminate tomatoes, you can also pinch the tips of the suckers, or small shoots, that start to form in the V-shaped crotches between the main stem and side stems. Pinching these suckers will prevent the growth of more side branches while speeding up the development of fruit. At the end of the growing season, cut the tip of every stem so the plant will focus its energy on ripening fruit quickly before the first frost.

Propagating Tomatoes

Pruning your plants will leave you with stem cuttings that can potentially be grown as new plants. This is best done earlier in the growing season, as tomato plants need time to mature and develop.

1. Fill a small pot with moist, lightweight potting soil enriched with compost.
2. Cut a tomato stem about six inches from the tip of the plant. Remove the bottom leaves from your stem (at least two should remain at the top), and stick the cutting two or three inches deep into the soil. You can use a pencil or chopstick to make the hole first so you won't damage the stem.
3. Place your cutting in a shady spot to protect it from direct sun. The stem should root easily as long as you water regularly to moisten the soil.
4. After a week, you can begin to gradually expose your plant to direct sunlight, beginning with a bit of morning sun.
5. After two weeks, give the cutting a quick, light tug to see if it has rooted—the plant should not come out of the soil with gentle pulling. Once your plant is well rooted, you can transplant it in the garden.

How to Grow Tomatoes From Seed

It's important to wait until the coldest weather has passed before planting tomatoes. Start your seeds indoors up to four to six weeks before the last frost date, and then transplant seedlings once warm weather arrives. They will be ready to transplant when they have multiple sets of leaves and have reached a height of six inches. Follow these steps to grow tomatoes from seed:

1. Fill a seed-starting tray or three- or four-inch pots with seed-starting mix and moisten.
2. Sow seeds 1/4-inch deep, one seed per cell, or two or three seeds per pot. Lightly cover and water seeds, then use a clear plastic dome or sheets of clear plastic to cover the pots and help maintain a moist environment.
3. Place near a sunny window or under grow lights in a room that stays between 60ºF and 70ºF. After the seeds sprout, remove any plastic. If the pots sprout multiple seeds, thin out the weaker sprouts. Water to keep the mix lightly moist, and provide strong light to prevent your plants from getting leggy, or long and scraggly.
4. Seeds that were started in cells can be transplanted into three- or four-inch pots once the roots outgrow their environment.
5. Once all danger of frost has passed, harden off your seedlings by placing them in a shady place outdoors and gradually exposing them to sunlight, starting with a bit of morning sun. Bring them in whenever temperatures fall under 45ºF. You can transplant them in the garden once nighttime temperatures stay above 55ºF.
   

Potting and Repotting Tomatoes

If you have poor soil or limited space, you can still grow tomatoes in a sunny spot on your patio or deck. There are many "patio tomatoes" and "bush tomatoes" out there that will do well in tomato planters, but you can experiment with old-fashioned tomatoes, too. Choose a pot with drainage holes that is 18 inches wide for determinate tomatoes or 24 inches wide for indeterminate tomatoes (a really small plant like 'Tiny Tim' can grow in a 10- or 12-inch pot) and follow these steps:

1. Fill the pot with high-quality potting soil. Mix in some compost if the potting soil does not already contain compost or fertilizer.
2. Dig a hole deep enough to bury about two-thirds of the stem. Pull your tomato plant from the nursery pot, remove the lower leaves, and set your tomato in the hole. Fill in with soil, and water well. Add a tomato cage or a large stake to help support the plant.
3. Add a thin layer of mulch on top of the soil. Place a saucer underneath the pot to help conserve moisture on hot days (the saucer can be removed during cool or rainy weather). Water the pot any time the top inch of soil is dry.
4. Fertilize about two weeks after planting and again every two weeks, using an organic, water-soluble fertilizer for vegetables.

Common Pests and Plant Diseases

Tomatoes might be easy to grow, but anyone who has planted them knows they are afflicted by countless diseases and are munched on by insects, birds, and squirrels. Plants shoot up rapidly, only to wilt and collapse, or produce a bumper crop of fruit that is quickly overtaken by bugs or ugly brown spots.

Start with good cultural practices: Don't plant tomatoes in the same spot every year, and if you have a diseased tomato plant, don't plant there again for at least three years. Remove weeds, which can harbor diseases and the pests that spread them. Get your soil tested, and add lime if it is too acidic to help reduce the spread of disease. Keep your plants well-watered, and fertilize at the appropriate time. And pick tomatoes just as they start to change color, stowing them away safely on your counter to finish ripening.

Though we all love heirloom tomatoes, you might want to choose new varieties that were bred to be resistant to disease. Look for codes such as "VFN" on the plant label, which means resistant to verticillium wilt, fusarium wilt, and nematodes. In the meantime, here are some of the most common tomato diseases:

• Bacterial wilt: Soil-borne bacteria fill up stems during hot and humid weather, causing your green plant to rapidly wilt. If you cut an infected stem crosswise, it will look brown inside. Pull and dispose of plants in a plastic bag—don't put them in your compost pile.
• Early blight: Fungi cause brown lesions on the leaves, starting at the bottom of the plant. The leaves may begin to yellow around the lesions. The fruit can develop leathery black spots that enlarge into a bull's eye. Trim off and dispose of infected leaves and fruit. For severely infected plants, apply a fungicide.
• Late blight: Lesions from this water-mold pathogen can appear on any part of the plant. Dark, water-soaked spots appear on leaves, or shiny brown or olive lesions appear on the fruit. White mold can eventually appear on the leaves around infected areas. Pull and dispose of diseased plants.
• Southern blight: The first sign of attack by this soil-borne fungus is a brown lesion on the stem close to the soil line. White patches may appear on the lesion. If the stem is girdled, the entire plant will wilt. Remove and dispose of infected plants quickly. You can try protecting healthy plants with a fungicide or neem oil, but the disease is difficult to control.
• Fusarium wilt: This fungus causes the lower leaves of a plant to droop or wilt. Leaves begin to turn yellow and eventually die. The stem appears brown inside. Pull and dispose of diseased plants.
• Tomato spotted wilt virus: This virus is spread by tiny insects called thrips that hang out in weeds around your garden. Plants can be stunted and leaves will develop bronze or dark spots. The fruit can develop yellow spots or darker spots and never ripen. Pull and dispose of diseased plants and spray healthy plants with neem oil or insecticidal soap.
• Tobacco mosaic virus: Leaves become mottled and deformed, often shoestring-like. Pull and dispose of diseased plants. Weed the area, and work to control pests like thrips and whiteflies.
• Septoria leaf spot: You'll first notice small dark circular spots with a light center on the leaves that are caused by a fungus. Leaves eventually turn yellow and fall off. Remove and dispose of diseased foliage, and improve air circulation around plants where possible. Spray plants repeatedly with fungicide to keep them in check.
• Anthracnose fruit rot: Anthracnose fungi cause depressions on tomatoes that begin to develop a black center. The indentations continue growing over time, with spores eventually emerging from the infected area. Harvest fruits frequently to reduce the spread.

Tomatoes are also susceptible to damage from a wide variety of pests. Pick off large caterpillars like cabbage loopers, hornworms, and cutworms, and drop them into a can of soapy water. Small caterpillars can be sprayed with Bt or insecticidal soap. Sap-sucking insects like aphids, whiteflies, and thrips can also be sprayed with neem oil or insecticidal soap if the problem becomes serious enough (aphids can alternatively be knocked off of plants with a strong stream of water). If you see long, thin beetles eating the foliage, you might have blister beetles. Put on a pair of gloves to protect your skin, and knock them into a can of soapy water with a stick.

There are plenty of insects that attack the fruit as well. Stink bugs are recognizable by a shield-shaped body. Bright orange leaf-footed bugs will cluster together on tomato plants. Both leave ugly blemishes on fruit but are difficult to control with insecticides, so you might have to resort to a can of soapy water for them as well.

Common Problems With Tomatoes

Weather or soil conditions also commonly lead to deformed fruit or foliage on tomato plants. Here are some other problems you may see and how to solve them.

Blossom-End Rot

This can be due to a lack of calcium in the soil or to inconsistent watering that interferes with the plant's uptake of calcium. As indicated by the name, the ends of the fruits begin to rot, creating dark sunken spots that render them inedible. While often seen in tomatoes, this issue can also afflict peppers, eggplants, and different kinds of squashes. Discard the affected fruits, water regularly, and apply tomato fertilizer that contains calcium.

Cracking Fruit

Cracking, when the skin of the fruit rips or cracks open, is usually the result of inconsistent moisture. Water regularly during dry spells to discourage cracking. Fruit can grow rapidly after a heavy rain and split; harvest ripening fruit before a heavy rain to avoid this issue. Very cold or hot weather may also cause cracking.

Catfacing

Catfacing is the term used for a fruit that is scarred, puckered, or distorted on the bottom. This usually occurs after extreme swings in temperature that affect flower formation and pollination. Though the fruit may be ugly, you can still eat it. To avoid catfacing, wait to plant tomatoes until the soil temperature reaches 65ºF, or a minimum of two weeks after the last frost of the year.

Whitish or Tan Spots on Fruit

This phenomenon is referred to as sunscald. Light tan or grayish spots develop on exposed sides of the fruit during hot, sunny weather. This is most common on plants that have lost a significant amount of foliage. Encouraging new leafy growth and using shade cloth over exposed tomatoes can help prevent this problem.

Leaf Roll

While rolled-up leaves can be a sign of disease, sometimes it's just a matter of needing more moisture. Water if needed, and know that this symptom doesn't necessarily harm your plant.

An herbicide used in some weedkillers, lawn weed-and-feed products, and agricultural products can also cause tomato leaves to roll up. Herbicides can also be present in straw. Don't use herbicides around your plants, and try to protect them from drift from spraying. Remove any straw you suspect may have been treated or exposed to herbicides.

Leaves Yellowing at the Stem End

If your tomato leaves develop yellow patches right at the stem, this also may have been caused by herbicide. Again, don't use herbicides anywhere near your plants.