1. Get Fresh Seeds
For the best chances of success, acquire your seeds from reputable commercial sources. As tomato seeds age, their germination rate decreases. It is best to use seed that is less than 4 years old; however, seed that is much older can usually be germinated if has been stored in cool and dry conditions.
2. Get a Seed Starting Mix
Garden soil is not a good choice, as it compacts too easily and can harbor organisms that cause diseases. A commercially prepared seed starting mix, usually a combination of peat moss, vermiculite and perlite, is recommended. Avoid mixes that have a high fertilizer content, as this causes more problems than good. Commonly used and recommended mixes are Jiffy Mix, ProMix, MetroMix and Fafard. Many other brands, or even homemade mixes, can be used.
Combine the seed starting mix thoroughly with warm water to bring it to a useable state. This may take quite a lot of mixing, as completely dry mixes can be difficult to wet. Sometimes it's best to let the moistened mix sit overnight to be sure that it is evenly wet. The final mix should be damp like a wrung-out sponge, not soaked or soggy.
3. Select Some Containers
Tomato seeds will germinate in anything as long as the seeds get moisture and warmth. After germination and initial growth, the seedlings need to be potted up to larger containers. Containers must be able to drain excess water. If using old or previously used containers, its best to sterilize them with a 10% bleach solution.
Your choice of containers for potting up depends on the number of plants you desire. Professional nurseries use growing "flats" with various-sized plastic cell inserts. Many sizes and kinds of flats are commercially available to the home grower, but they are not essential.
Many home growers use styrofoam or plastic drinking cups with holes poked in the bottom. Just about anything will work as long as excess water can drain.
4. Determine When to Start
Many novices fail at starting tomatoes simply because they start too early. Given the proper care, full-sized tomato transplants can be grown in 6 to 8 weeks.
Before planting seeds, you must determine when your plants can be safely placed into the garden. Planting outdoors is best done about 1 or 2 weeks after the average last frost date for your area.
Ask friends or use web resources to find your average last frost date, then do the math to calculate your seed starting date.
5. Plant Your Seeds
Fill a small container with damp seed starting mix. Plant your seeds about 1/8 inch (3 mm) deep. Firm the mix lightly to ensure that the seed is in direct contact with the moist mix. The seed needs to absorb moisture during the germination process.
You can plant lots of seeds close together because the resulting seedlings will be moved to larger containers after germination (when the first true leaves appear).
It is a good idea to provide some sort of covering over your germination containers to preserve moisture. You can place the container in a plastic bag or cover it with a sheet of plastic. Allow for some air to circulate but don't let the mix dry out. Dry seeds will not germinate.
6. Patiently Wait for Germination
Place the germination container in a warm location out of direct sunlight. Light is not needed during the germination process, but will not be harmful as long as high temperatures are avoided.
Tomato seeds usually germinate within 5 to 10 days when kept in the optimum temperature range of 70 to 80F (21 to 27C). Germination is delayed by lower temperatures and accelerated by higher temperatures. Temperatures below 50F (10C) or above 95F (35C) are detrimental to germination.
Keep a close eye on the first seedlings, as they need to be moved into bright light as soon as they emerge from the soil. They will explosively reach for light, and if the light is not adequate, you will get 3-inch-long (8 cm long) stems shortly after germination - this is very undesirable. If this occurs, you could try to transplant to a deeper container, or you may want to start over.
7. Put the Seedlings under Light
Very strong light is needed to support tomato growth. A heated greenhouse is the ultimate location to continue growing your seedlings. A second choice would be a cold frame (possibly with supplemental heat for cool nights).
Many home growers use inexpensive fluorescent shop lights. A south-facing windowsill can work but usually presents more problems than the fluorescent shop light setup.
If fluorescent shop lights are used, the leaves of the plants must be within inches of the bulbs. Use your own creativity to make a setup that gets the plants directly under the bulbs. The lights should remain on for 16 to 18 hours per day.
8. Monitor the Plants as They Grow On
Tomato seedlings grow best at a temperature of about 65F (18C) with some air circulation and lots of light.
When watering, most growers soak the mix and then let it get nearly dry before providing more water.
When the plants develop their first true leaves, they should be transplanted into larger individual containers. The plants actually benefit from this re-potting step, as it helps them develop a strong root system. The plants may be set deeply into their new containers to shorten the height of the seedling.
Most commercial seed starting mixtures have a small amount of fertilizer that will support small seedlings for some time. Depending on the components of your starting mix, you may need to begin fertilizing. If you do fertilize, do it very, very sparingly with a weak dilution.
Depending on the size of your containers and your growing conditions, you may need to pot up a second or third time to prevent your plants from becoming root bound.
The plants require good lighting to continue to grow well. Place the plants where they get plenty of sunlight, and if that is not possible or adequate, use fluorescent fixtures, or specialized high-intensity grow lamps, or use a combination of natural and artificial lighting.
Keeping large tomato plants indoors, under artificial lighting, can be quite difficult. To avoid problems, don't start too early. The best solution to the lighting dilemma is to plan your seed starting date so that the transplants reach a reasonable size along with the arrival of suitable outdoor temperatures.
9. Harden Off your Transplants
Introduce the plants to outdoor conditions slowly. This is called "hardening off". If it is not done slowly your plants may be shocked and their growth may temporarily cease.
The longer the plants remains indoors, the harder it will be to acclimate them to the outdoors. Avoid full sun and wind when you first move them outside.
Cold frames can be used to harden off the plants. The covers can remain in place on inclement days and removed on moderate days.
Temporary structures can be built from plastic sheeting. Buildings and fences can be used to provide sun and wind protection while the plants adapt to outside conditions.
If really cold weather is forecast <40F (4C), it is best to bring the plants back inside. Freezing temperatures will destroy your plants (and it happens fast).
After the transplants are hardened off, they can be planted to their final outdoor growing locations either in the garden or in large growing containers. Most agree that any early blossoms should be plucked off prior to transplanting. Others leave the early blossoms in place, especially if the transplant is strong, healthy, and not root bound.
The plants can become "leggy," the stems being elongated and limp, and the foliage sparse. Leggy seedlings usually occur due to insufficient lighting, too much heat, or too much fertilizer. Suggested remedies, short of starting over, are to repot the plants deeper as described earlier in Step 8, and to use a fan to improve air circulation and keep temperatures moderated, resulting in stockier and stronger plants.
Characterized by lack of germination (pre-emergent) or causes narrowing of the newly emerged stems at the soil line and the tiny seedlings then flop over and die (post-emergent). Various fungi are responsible for the condition and they are found in high concentrations in any mix with real soil. That's why it's best to use the artificial seed starting mixes mentioned in step 2. Also, it's very important to be sure that plastic domes or baggies on your containers are not airtight. If these precautions are observed, it is unlikely that you will experience damping off.
When seedlings refuse to grow it is usually because the temperature is too low or the nutrient level is insufficient.
Sometimes the cotyledons (the first leaves formed from the seed) have trouble getting loose from the seed coating. Be patient, as the leaves will usually escape. You could wet the seed coating, or you could try to carefully pinch off the seed coat, but if you pinch off the cotyledons, the seedling will likely die. A simple way to wet the seedlings is with a spray bottle of water set to mist. A small drop of saliva is also very effective at loosening seed coats.
Many growers fail with tomato plants because they over-water. Soggy soil will cause seed to rot. Once the seedlings are growing, they should be watered thoroughly then left un-watered until they are almost ready to wilt.
Over fertilizing can cause seedlings to die, to stop growing, or to grow rapidly into spindly plants. One or at most 2 applications of very dilute fertilizer are adequate to get a seedling through to transplant size.
How to grow great tomatoes.
Plant tomatoes where they will get at least 10 hours of light in summer. And leave room between plants for air to circulate.
2. Rotate even a little.
Alternate your tomato bed between even just two spots and you diminish the risk of soilborne diseases such as bacterial spot and early blight.
3. Pass up overgrown transplants.
When buying tomato seedlings, beware of lush green starts with poor root systems. They will languish for weeks before growing.
4. Bury the stems.
Plant your tomato seedlings up to the first true leaves. New roots will quickly sprout on the stems. More roots means more fruits.
5. Water deeply but infrequently.
Soak your tomato bed once a week, or every five days at the height of summer. Water directly on the soil, not on the leaves.
6. Pinch the suckers.
Prune off these non-fruiting branches. This directs the tomato plant's energy into growing bigger, better fruit.
7. Stake them high.
Use 6-foot stakes for indeterminate varieties like the 'Brandywine' tomato. Put in the stakes when transplanting to avoid damaging roots.
8. Add compost and trim.
While the first fruit is ripening, encourage new growth and continued fruit set by scratching compost around the stem, and trim some of the upper leaves.
9. Plant again.
Three weeks after you plant tomatoes in your garden, put in another set so all of your harvest doesn't come at once.
10. Pick ripe, but not dead ripe.
Heirloom tomatoes that are too ripe can be mealy. Harvest them when they're full size and fully colored.
Even more tips for fantastic tomatoes.
A vegetable garden isn't complete without tomatoes.
Since tomatoes are America's favorite garden vegetable, it's no surprise that there are hundreds of varieties to choose from. Home garden tomatoes range from bite-size currant, cherry, and grape tomatoes to huge beefsteak fruits, in nearly every color except blue. You can grow tomato varieties that produce fruit extra early, and there are varieties for every type of climate, including many that are resistant to one or more common tomato diseases. Don't forget tomatoes especially developed for slicing, canning, juicing, or stuffing, too.
Discovering which tomato varieties are best for your garden will involve some experimenting, and your climate and personal taste will play a role, too. Some early types such as 'New Girl' and 'First Lady II' will be ready to pick about two months after you set plants in your garden, while main-season hybrid and heirloom varieties can take up to 80 days. To extend your harvesting season, be sure to plant some of each type.
Many standard cultivars are adapted for a variety of uses, including slicing, canning, and salads. The large, meaty fruits of beefsteak tomatoes are especially popular for slicing. Italian or paste tomatoes are favorites for cooking, canning, and juicing. Sweet bite-size tomatoes in a range of colors are very popular for salads or as snacks.
Tomato plants are vines, and they have two basic ways of growing, called determinate and indeterminate. The vines of determinate varieties (sometimes called bush tomatoes) grow only 1 to 3 feet long, and the main stem and side stems produce about three flower clusters each. Once flowers form at the vine tips, the plant stops growing. This means determinate types set fruit over about a two-week period and then stop, which makes them excellent choices for canning. Indeterminate tomatoes have sprawling vines that grow 6 to 20 feet long. Most produce about three flower clusters at every second leaf. They keep growing and producing unless stopped by frost, disease, or lack of nutrients, which means you can keep picking fresh tomatoes the whole season. Pruning is necessary, however, or they will put too much energy into vine production.
Nurseries and garden centers offer a wide range of dependable, disease-resistant varieties such as 'Jet Star', 'Celebrity', and 'Sweet 100', and many sell transplants of popular heirloom tomatoes such as 'Brandywine', 'Green Zebra', and 'Cherokee Purple' as well. But if you want to take advantage of the full range of available cultivars, you'll have to grow tomatoes from seed. Unless you plan to preserve a lot of your crop, 3 to 5 plants per person is usually adequate. Unused seeds are good for 3 years. Specialty mail-order suppliers also offer individual tomato plants for sale, which could be a good option if you don't have space for growing your own from seed.
At 6 to 8 weeks before the average last frost, sow seeds ¼ inch deep and 1 inch apart in well-drained flats. Seeds will germinate in about 1 week when the soil temperature is 75° to 85°F; at 60°F the germination process can take 2 weeks.
In most places, a sunny spot indoors, such as a south-facing window, provides the warm, humid environment young seedlings need. If you don't have sunny windows, use a heating coil for bottom heat and a fluorescent or grow light overhead. Lack of adequate light will make seedlings leggy and weak.
Once the seedlings emerge, keep the temperature no higher than 70°F, and water regularly. Once a week, feed with compost tea or fish emulsion, and discard any weak or sick-looking seedlings. When the second set of leaves—the first true leaves—appear, transplant to individual pots or deep containers (such as plastic cups), burying the stems deeper than they stood previously. Whatever container you use, make sure it has drainage holes in the bottom. After this initial transplanting, give the seedlings less water and more sun. As the weather warms, harden off the plants before planting them in the garden. Again, discard any weaklings that might harbor disease.
If you buy a four-pack or six-pack of transplants from a garden center, it's a good idea to transplant them to individual pots and harden them off for a week or two before setting them out in the garden. They'll have a more vigorous root system and you can make sure that the soil is warm and the weather settled before planting day.
Except in extremely hot climates, plant tomatoes where they will get full sun. To lessen shock, though, transplant seedlings on a cloudy day. Make the planting holes larger than normal for each seedling; cover the bottom of the hole with several inches of sifted compost mixed with a handful of bonemeal. For magnesium, which promotes plant vitality and productivity, sprinkle 1 teaspoon of Epsom salts into each hole. Disturb the soil around seedling roots as little as possible when you set them in contact with the compost.
Set the transplant so the lowest set of leaves is at soil level; fill the hole with a mixture of compost and soil. Or you can bury the stem horizontally in a shallow trench so that only the top leaves show; make sure you strip off the leaves along the part of the stem that will be buried. Many growers claim this planting method produces higher yields. Press down the soil gently but firmly to remove air pockets, and water well.
If you're planting a bit early, or in general want to speed the growth of your tomatoes, you can shelter them with a commercial device such as a Wall O' Water or simply wrap tomato cages with clear plastic.
Spacing between planting holes depends on how you grow your tomatoes. If you're going to stake and prune the plants or train them on trellises, space the seedlings 2 feet apart. If you plan to let them sprawl, space them 3 to 4 feet apart.
Letting plants sprawl involves less work, but it requires more garden space. And unless protected by a very thick mulch, the plants and fruits are also more subject to insects and diseases due to contact with the soil—not to mention being more accessible to four-legged predators, such as voles.
If you plan to train your tomato plants on stakes or in cages, install the supports before planting. Pound 5- to 7-foot-long stakes 6 to 8 inches in the ground or insert the cages (it's a good idea to secure cages with stakes, too). As the vines grow on staked tomatoes, tie them loosely to the stake at 6-inch intervals with soft twine or strips of cloth or panty hose.
There are also ready-made tomato cages, but they are expensive to buy and usually aren't tall enough. For details on making your own tomato cages, see "Super Sturdy Tomato Cages".
Any slight frost will harm young tomato plants, and nighttime temperatures below 55°F will prevent fruit from setting. In case of a late frost, protect transplants with cloches or hot caps, because cold damage early in a tomato's life can reduce fruit production for the entire season.
Cultivate lightly to keep down any weeds until the soil is warm, then lay down a deep mulch to smother the weeds and conserve moisture. Give the plants at least 1 inch of water a week, keeping in mind that a deep soaking is better than several light waterings. Avoid wetting the foliage, since wet leaves are more prone to diseases.
A weekly dose of liquid seaweed will increase fruit production and plant health, as will side-dressing with compost two or three times during the growing season.
If you stake your plants, you may want to prune them to encourage higher yields. Pruned tomatoes take up less space and are likely to produce fruit 2 weeks earlier than unpruned ones; they do, however, take more work. Pruning tomatoes is different from pruning trees and shrubs—the only tools you should need are your fingers. You'll be removing suckers, which are small shoots that emerge from the main stem or side stem at the base of each leaf.
Leave a few suckers on the middle and top of the plant to protect the fruit from sun scald, especially if you live in a hot, sunny area, such as in the South. Sun scald produces light gray patches of skin that are subject to disease. When the vine reaches the top of the stakes or cage, pinch back the tips to encourage more flowering and fruit.
Helpful hint for pinching tomato suckers
Use your thumb and forefinger to snap off the small, tender shoots that sprout at the base of tomato leaf stems. If you need to use scissors or pruning shears, you've waited too long.
Although tomatoes are potentially subject to a range of pests and diseases, plants that are growing in rich soil with adequate spacing and support to keep them off the soil usually have few problems. Here are some of the common potential tomato problems:
- The tomato hornworm—a large, white-striped, green caterpillar—is an easy-to-spot pest. Just hand pick and destroy, or spray plants with Bt (Bacillus thuringiensis). If you're hand picking, check to see whether horn-worms have been attacked by parasitic wasps first—if they have, the wasp larvae will have pupated, forming structures that look like small white grains of rice on the back of the hornworm. Leave these hornworms be so the wasps can spread. Also, plant dill near your tomatoes. It attracts hornworms, and they're easier to spot on dill than they are on tomato plants.
- Aphids, flea beetles, and cutworms may also attack your tomato plants.
- Hard-to-spot spider mites look like tiny red dots on the undersides of leaves. Their feeding causes yellow speckling on leaves, which eventually turn brown and die. Knock these pests off the plant by spraying with water, or control with insecticidal soap.
- If you are new to growing tomatoes, check with your county extension agent to find out what diseases are prevalent in your area. If you can, choose varieties that are resistant to those diseases. Such resistance is generally indicated by one or more letters after the cultivar name. The code "VFNT," for example, indicates that the cultivar is resistant to Verticillium (V) and Fusarium (F) wilts, as well as nematodes (N) and tobacco mosaic (T).
- Nematodes, microscopic worm-like creatures, attack a plant's root system, stunting growth and lowering disease resistance. The best defenses against nematodes are rotating crops and planting resistant cultivars.
- Verticillium wilt and Fusarium wilt are two common tomato diseases. Should these wilts strike and cause leaves to curl up, turn yellow, and drop off, pull up and destroy infected plants, or put them in sealed containers and dispose of them with household trash.
- Another disease, early blight, makes dark, sunken areas on leaves just as the first fruits start to mature. Late blight appears as black, irregular, water-soaked patches on leaves and dark-colored spots on fruits. Both blights tend to occur during cool, rainy weather. To avoid losing your whole crop, quickly destroy or dispose of affected plants. The best defense is to plant resistant cultivars. Bicarbonate sprays can also help prevent the disease from infecting your plants.
- Blossom drop, where mature flowers fall off the plant, is most prevalent in cool rainy weather or where soil moisture is low and winds are hot and dry. It can also be from a magnesium deficiency or from infection by parasitic bacteria or fungi. Large-fruited tomatoes are particularly vulnerable. Fruit set can sometimes be encouraged by gently shaking the plant in the middle of a warm, sunny day or by tapping the stake to which the plant is tied.
- Blossom-end rot appears as a water-soaked spot near the blossom end when the fruit is about 1/3 developed. The spot enlarges and turns dark brown and leathery until it covers half the tomato. This problem is due to a calcium deficiency, often brought on by an uneven water supply. Blossom-end rot can also be caused by damaged feeder roots from careless transplanting, so always handle seedlings gently. Try to keep the soil evenly moist by using a mulch and watering when needed.
- Prolonged periods of heavy rainfall that keep the soil constantly moist can cause leaf roll, which can affect more than half the foliage and cut fruit production significantly. At first, the edges of leaves curl up to form cups; then the edges overlap and the leaves become firm and leathery to the touch. Keeping soil well drained and well aerated is about the only method of preventing this problem.
- Fruit with cracks that radiate from the stems or run around the shoulders are often caused by hot, rainy weather or by fluctuating moisture levels in the soil. Such cracks, aside from being unsightly, attract infections. To avoid them, make sure you don't over water.
- Tomatoes—like eggplants, potatoes, and peppers—are related to tobacco and subject to the same diseases, including tobacco mosaic. Therefore, don't smoke around such plants, and wash your hands after smoking before handling them. Plan your garden so that nightshade-family crops, such as peppers and tomatoes, are separated by plants from other families.
Once tomatoes start ripening, check the vines almost daily in order to harvest fruits at their peak. Cut or gently twist off the fruits, supporting the vine at the same time to keep from damaging it.
Most plants can survive a light frost if adequately mulched, but at the first sign of a heavy frost, harvest all the fruits, even the green ones. To continue enjoying fresh tomatoes, cut a few suckers from a healthy and preferably determinate plant and root them. Plant in good potting soil in 3-gallon or larger containers. Keep in a warm, sunny spot, and with a little luck and care, you can enjoy fresh tomatoes right through winter.
Ripe tomatoes will keep refrigerated for several weeks, but their taste and texture will decline. Green ones will eventually ripen if kept in a warm place out of direct sunlight. To slowly ripen green tomatoes, and thereby extend your harvest, wrap them in newspaper and place in a dark, cool area, checking frequently to make sure that none rot. Sliced green tomatoes are delicious when lightly dipped in egg, then in flour or cornmeal and black pepper, and fried.
Tomatoes in Small Spaces
Even if you don't have much room to grow vegetables, you can still enjoy the taste of a fresh-picked tomato. Tomatoes are easy to grow in containers, making them perfect for decks, patios, or balconies. If you have the space, try growing full-size tomatoes in large fiberglass tubs or wooden barrels. For people with less room, there are dwarf cherry tomato cultivars, such as 'Tiny Tim' and 'Pixie Hybrid II', that can grow in 6-inch-deep pots.
All container tomatoes need lots of sun, plenty of water, and a rich, well-drained potting mixture. Compensate for the restricted root zone by applying liquid fertilizer, such as compost tea, lightly but frequently, increasing both water and nutrients as the plants grow.