Tomatoes are by far the most popular home garden crop in America, and it’s clear why. You’ll never eat a tomato that tastes better than one you picked from your own garden. If you want to grow tomatoes for the first time or are looking to up your tomato-growing game, here’s what you need to know.
You can also download my How Do I Grow Tomatoes? one-sheet and keep the free resource handy for your reference.
Though a red, round, baseball-size fruit may be what comes to mind when picturing a tomato, tomatoes come in many different sizes and shapes with a rainbow of colors as well. Flavor profiles are also different from one variety of tomato to the next, and some varieties are better suited to certain uses than others, like how paste tomatoes are used in making sauce and how beefsteak tomatoes make the best slices to top a burger.
There are a number of pests and soil-borne and air-borne diseases that affect tomatoes, but these challenges can be overcome with knowledge and perseverance. Having a better understanding of how to keep your tomato plants growing strong, and knowing what you are dealing with when challenges strike, will make your tomato growing experience more fun and rewarding.
When and How to Start Tomatoes
Tomato seeds should be started indoors six to eight weeks before the seedlings are planted outside. Tomato plants will die in frost, so plan to plant the seedlings out after your area’s last possible frost date.
Sow tomato seeds a quarter-inch deep in sterile seed-starting mix, and if necessary, use a seedling heat mat to maintain a soil temperature of between 70° and 85°F for faster germination. In general, the seeds should germinate in about a week, but the closer the soil temperature is to the upper end of that range, the faster that will happen. However, even in the optimal temperature range, some varieties may take up to two weeks to germinate.
Tomato seedlings should be kept under grow lights to reduce the chances of them becoming leggy and weak. Strong, compact seedlings are what you want, and supplemental lighting helps with that. It also helps to run a fan gently on the seedlings to prevent damping off disease, which is a fungus that is fatal and appears very early in the germination process.
Tomato seedlings can grow significantly over those first six to eight weeks inside. So, in order to provide sufficient room for the roots to continue to spread, they will likely need to be “potted up” to larger containers before they’re ready to be planted outside.
Tomato seedlings should be planted deep when potted up because they will grow new roots out of the buried stem, and having more roots means a greater ability to take up water and nutrients. Potting deep can also help leggy seedlings become stronger.
Alternatively, pick up seedlings from a nursery. Beginning with greenhouse-grown tomato seedlings is certainly convenient. Just keep in mind, there will be less variety to choose from when buying plants rather than seeds.
Where and How to Plant Tomatoes
Before tomato seedlings are planted outdoors, they should be gradually introduced to the new environment in a process known as “hardening off.” This involves putting seedlings out in the sun for a short time on the first day — a half hour — and gradually increasing the time spent outdoors each day for a week to 10 days, so by the end, the plants will be ready to receive a whole day’s worth of sun.
Tomato plants require full sun, which is considered to be between six and eight hours of direct sunlight daily. The soil should be well draining and amended with plenty of compost and other organic matter.
Tomatoes grow best in soil with a pH between 6.5 and 7.0, which is a range of slightly acidic to precisely neutral. Adding compost will help bring the pH into balance, but a soil test will remove any guesswork. The test results will include the soil’s pH and nutrient makeup, so you’ll know what amendments to make, if any.
Air circulation and sunlight into the plant are important. Therefore, spacing tomato seedlings at least 24 inches apart is recommended.
If growing determinate tomatoes, install a tomato cage when transplanting. If growing indeterminate tomatoes, install a stake when transplanting. (More on the difference between determinate and indeterminate below.) Adding supports once plants have grown larger is a risky endeavor because stem damage can easily occur.
Because tomato plants readily grow roots from their stems, seedlings can be planted deep. Remove the lower leaves with scissors or bypass pruners, and bury up to two-thirds of the plant. An especially tall seedling can be planted horizontally rather than deep to bury most of the stem; this is known as trenching. Whatever method you use, the goal is to have two or more sets of leaves above the soil. Backfill the hole with the soil, and water thoroughly.
Types of Tomatoes
There is so much diversity among tomatoes, and so much to learn. All tomato plants are the same species, Solanum lycopersicum, but the variety is endless.
One of the first things to look for when choosing a tomato variety to grow is whether it is a determinate tomato or indeterminate tomato. Determinate tomato plants get to be a certain size, produce many fruit within a short time, and then stop producing. Indeterminate tomato plants keep growing and will keep producing fruit until they are killed by frost in the fall.
Another big distinction is bush-type and vining-type. For the most part, bush-type tomatoes are the determinants and vining-type tomatoes are the indeterminates. But that is not a hard-and-fast rule since there are bush-types that will supply a continuous crop until frost. Bush-types are sometimes labeled as “container” tomatoes because they stay rather small and are ideal for containers or grow bags.
Breaking it down further, there are cherry tomatoes, grape tomatoes, beefsteak tomatoes, and plum (or paste) tomatoes.
Then there is the difference between hybrid tomatoes and open-pollinated tomatoes. A hybrid tomato is a cross between two parents that produces a plant and fruit with desired qualities, like a certain taste, size or growth habit and disease resistance. This is done through controlled cross-pollination. But seeds saved from a hybrid tomato will not grow to have the same predictable qualities.
An open-pollinated tomato grows true to seed, meaning if its seeds are saved and planted, the offspring will be just like the original tomato. (However, if an open-pollinated tomato is unintentionally cross-pollinated with another variety through wind or insect activity, all bets are off.) Open-pollinated tomatoes with a long history of being passed down through several generations (and often with a great story) are referred to as heirloom tomatoes.
Hybrid tomatoes are reliable crops, and the varieties specifically bred for disease resistance can help gardeners overcome a recurring pathogen. Commercially grown hybrids are often selected for disease resistance as well as consistency of shape and color and their durability during shipping and storage.
Heirloom tomatoes are often selected for flavor and visual interest above all else. There are surely red heirloom tomatoes, but there are many varieties that have tones of blue or purple. Others are green, yellow, orange and even striped when ripe. Some are ribbed or oddly shaped.
Cherry tomatoes are so named for their size and shape. Whole or sliced in half, they go great in salads — or just eat them like candy. They can also be roasted or sauteed. Black cherry, indigo cherry, white cherry, Gold Nugget and Sunrise Bumble Bee are a few open-pollinated cherry tomatoes. Among the hybrids are Sakura, Tomatoberry Garden, Supersweet, Cherry Bomb and the intensely flavored Sun Gold.
Grape tomatoes are even smaller than most cherry tomatoes, and they are oblong like grapes. Enjoy them the same way you’d enjoy cherry tomatoes. A few open-pollinated grape tomato varieties are Red Pearl, Principe Borghese and Ildi. Some hybrid varieties are Five Star Grape, Valentine, Sweet Hearts, Ruby Crush, Nova, Apero, Golden Sweet, Gold Spark and Paresco.
Plum tomatoes, also known as paste tomatoes, are what to grow if wanting to make sauce or canned tomatoes. The most popular variety is the Roma, an open-pollinated, determinate tomato.
Beefsteak tomatoes are some of the largest tomatoes. Many grow to be more than 1 pound per fruit, and the world-record tomato was 10 pounds. Slice these tomatoes to top a sandwich or another dish, or have a caprese salad of tomato slices, mozzarella and basil. Mortgage Lifter, Brandywine, Black Krim, Paul Robeson and Cherokee Purple are popular heirloom-type beefsteak tomatoes. Beefmaster VFN and Celebrity are disease-resistant hybrids.
A number of hybrid tomatoes are a bit too small to be called beefsteak but are still a good size for slicing or dicing. Better Boy, Early Girl, Summer Girl and Better Bush are just a few of the countless varieties. And new tomatoes are introduced every year.
Tomatoes benefit from plenty of water, up to 2 inches during the hottest period of summer. If it has rained any less than an inch in a week’s time, make up the difference with supplemental irrigation. Water under the foliage, right at ground level. (Overhead watering leaves the fruit and foliage wet, which invites disease.)
A drip irrigation system will prevent vulnerable seedlings from drying out and will keep water off the foliage of mature plants — it’s much more convenient than trying to hand water under a patch of big, leafy plants.
A 2-inch layer of organic mulch will help the soil retain moisture between waterings. Shredded leaves, bark, arborist’s wood chips and straw are all good mulch choices.
If you amended the soil with plenty of organic matter at planting time, those amendments should supply all or most of the nutrients your plants need. However, it wouldn’t hurt to add additional fertilizer into the soil before planting or to provide supplemental feedings every three weeks with a natural fertilizer.
As an organic gardener, I use organic fertilizer options with an NPK ratio that is balanced, like a 4-4-4. NPK stands for nitrogen, phosphorus and potassium. During the early growth phase, the number representing nitrogen can be higher than the other numbers since it promotes vegetative growth.
However, once flowering and fruiting begin, the amount of phosphorus should match or exceed the amount of nitrogen. Otherwise, all that nitrogen will lead to a lot of foliar growth at the expense of fruit development. Something like a 3-4-6 or 3-5-3 organic fertilizer is a better choice than a high-nitrogen synthetic fertilizer.
Never apply more fertilizer than the manufacturer’s instructions call for. More does not equal better, as over-fertilizing can cause more harm than good.
Various pests and a number of fungal and bacterial diseases affect tomato plants. Good garden sanitation practices, crop rotation and the use of resistant varieties will all cut down on issues — and diligence helps too. The best thing for a garden is a gardener’s shadow because pest and disease problems are easiest tackled when discovered early.
To find a variety that’s resistant to a disease that had troubled your garden, look for these letters on the plant tag: A for alternaria, F for fusarium wilt, LB for late blight, N for nematodes, T for tobacco mosaic virus and V for verticillium wilt.
Alternaria, also known as early blight, causes dark, half-inch leaf spots, starting on the oldest leaves. The spots can spread to stems, which can be fatal to young plants. To prevent recurrences, remove the leaf litter from the garden and do not save the seeds.
Anthracnose is a fruit rot fungus found on ripe and overripe fruit, presenting as small, round depressed areas that turn black. Do not leave infected fruit in the garden, as the fungal spores will easily spread to other fruit and to the soil when water splashes around, and do not save seeds from infected fruit. If anthracnose becomes a recurring problem, choose resistant varieties, like Better Boy or Bradley.
Blossom end rot (not a disease but often confused as such) is a symptom of calcium deficiency usually due to inconsistent water. Watering on a regular schedule can often resolve this issue. A calcium deficiency in the soil is rare. Get a soil test to identify deficiencies or excess nutrients if the watering schedule has not helped.
Canker is a bacterial disease that turns the margins of leaves brown and yellow. As bacteria clogs the veins of the plants, the leaves begin to curl and wilt. Small brown spots, sometimes with white borders, will develop on fruit. Canker may arise due to using infected seeds or through wind or water that is carrying the bacteria from infected plants and soil. If plants show symptoms early, remove the affected plants to reduce the spread. If the plants have fruit on, you may be able to get a harvest before the plants succumb.
Fusarium wilt and Verticillium wilt can cause tomato plants to wilt and die. Affected plants should be disposed of outside of the garden to prevent recurrences and spread. These diseases are found in the soil so practice crop rotation by refraining from growing nightshades (tomatoes, peppers, potatoes) in that spot for three years, if not longer.
Late blight is so named because it arrives late in the growing season. It is a water mold that affects leaves, stems and fruit. Brown blotches appear on leaves and the fruit become brown and rot. Late blight prefers wet, cool weather, between 60° and 70°. Choose resistant varieties and remove nightshade weeds or volunteer potatoes that are also vectors for late blight.
Tomato root knot nematodes form galls in tomato roots where they steal nutrients. If you go heavy on water and fertilizer, an affected tomato plant may still be able to produce. It’s said that interplanting French marigolds with tomatoes will repel nematodes. However, if you know nematodes are present, plant resistant varieties or practice crop rotation by refraining from planting nightshades in that garden bed for three or four years, so the nematode population subsides.
Powdery mildew is a fungal disease that sometimes affects tomato plants. Proper spacing of plants to provide air circulation can reduce the chances of powdery mildew from becoming an issue. A solution of baking soda or diluted milk can slow the spread or be used as a preventative measure. (Read my comprehensive guide to powdery mildew control for more.)
Septoria leaf spot is a fungal infection that causes dark brown spots with black specks on the lowest, oldest leaves. Copper fungicide is one organic control method, or chose resistant varieties such as Iron Lady, Stellar and BrandyWise to begin with.
Tobacco mosaic virus affects its namesake tobacco as well as tomatoes and other nightshades. There is also tomato mosaic virus, which is difficult to distinguish from tobacco mosaic virus. Both prefer it warm. These viruses cause tomato leaves to turn mottled with dark and light coloration, and leaves may curl or not grow to full size. An affected plant will have fewer and smaller fruit and uneven ripeness. To prevent spread, remove affected plants from the garden and dispose of them. Do not add the plants to compost, where the virus can survive.
Tomato spotted wilt virus is a disease that is a big problem in the Southeast. It is spread by thrips and can stunt growth and kill plants when infection occurs early. If this is a problem where you are, grow BHN444 hybrid tomatoes, which are TSWV resistant.
Aphids are sucking insects that are vectors for plant diseases. As they feed on plant leaves they excrete honeydew, which attracts ants and other insects. They are easily controlled by knocking them off plants with a sharp stream of water or insecticidal soap.
Cutworms, sometimes called tomato worms, wrap themselves around the stems of young plants and chow down. They are actually moth larvae and can be controlled with paper collars around the stems.
Fruitworms and armyworms are moth larvae that bore into the fruits themselves. Handpick eggs on stems, under leaves and on fruit, and pick off any caterpillars, which may be green or black and gray. Bt is an organic control for moth and butterfly larvae that is safe around humans and pets and will not harm other wildlife. Just be sure not to apply it around butterfly larvae host plants such as milkweed and fennel.
Flea beetles are small black or bronze jumping leaf beetles, just an eighth of an inch long. These chewing insects can be kept off young tomato plants with floating row cover. Another strategy is to plant a trap crop of radishes, which flea beetles prefer over tomatoes. By summer, tomato plants are big and strong enough to shrug off flea beetle damage, and their presence then should not raise concerns.
Tomato hornworms, the larvae of hawkmoths, can be devastating to tomato plants. The green caterpillars with namesake horns on their rear ends grow to be between 2 and 4 inches long. Because of their size, they are easily handpicked. It’s easier to spot them at night with a UV flashlight. A parasitoid wasp known as the Cotesia wasp lays its eggs in hornworms, so a hornworm with white cocoons sticking out of its body should not be killed, so a new generation of Cotesia wasps will follow to continue to control the hornworm population. Tobacco hornworms are similar looking and they also eat tomato plants. Bt can also be used for hornworm control.
Whiteflies are similar to aphids in that they suck sap and cover plants in honeydew. They are naturally controlled by wasps, but tomato plants can also be treated with insecticidal soap.
When a tomato is at its full color and the flesh is firm but yields slightly to pressure, it’s at peak ripeness and ready to be picked. Enjoy a ripe tomato right away or within two or three days.
Tomatoes may also be picked at the “breaker stage.” This stage is when the fruit begins to blush or starts to show color (about 40% of its full color when ripe is a good guide). You can pick it now with the full assurance that it will continue to ripen to full flavor and color indoors. Picking at the breaker stage prevents cracking and ensures you get to the fruit before a critter does. Another reason to pick at the breaker stage is if frost is forecast.
Ripe tomatoes will last a couple of days on the counter or up to a week in the refrigerator. Tomatoes tend to lose flavor in the fridge, but if they are taken out and brought to room temperature before eating, some of that flavor returns.
What are your secrets to successfully growing tomatoes? Let us know in the comments below.
Ready to have more of your gardening questions answered? Sign up to receive gardening resources, eBooks and email updates on the joegardener podcast and more.
Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges.
joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.
Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Exmark, Greenhouse Megastore, High Mowing Organic Seeds, Territorial Seed Company, Wild Alaskan Seafood Box and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.