Not all tomato plants are the same so it's important to know what kind you're growing. Determinate tomatoes are also called bush tomatoes. They seldom grow more than three or four feet tall and often don't require any additional staking or support. All of the fruit reaches maturity at about the same time so the harvest will only last over a period of a few weeks. If your plant suddenly stops producing flowers and fruit, even when everything else is perfect, it's probably a determinate variety.
Indeterminate tomatoes may also be called vining tomatoes and can grow as much as eight feet tall. They don't produce fruit all at once but rather they provide fewer fruit at any one time, but over a longer period of time. Indeterminate tomatoes will usually give you a harvest until the first frost in fall.
How you grow these different types of tomato can impact how successful you are. For container gardening, like in pots on a patio, determinate tomatoes are the way to go; indeterminate ones can quickly overrun your space. If you like to "put up" tomatoes in quart jars or as tomato sauce, determinate plants will provide a harvest that you can can right away. If you like to have a few tomatoes to enjoy with your meals throughout the summer, indeterminate is the way to go.
Many gardeners believe heirloom tomatoes taste better than hybrids. That can be a matter of personal preference, but there are other obvious differences between the two. Typically, heirloom tomatoes have more problems with diseases and pests; hybrids have been developed to overcome these limitations. Heirloom tomatoes tend to take a long time to reach maturity and harvest; hybrids can be selected with very short "days to harvest".
If you have a garden in an area susceptible to tomato diseases, you may want to select a hybrid tomato with letters after its name (like VFN); the letters identify resistance to disease. If you garden with a short growing season, you can select hybrid varieties that will ripen early.
Hybrids tend to follow a pattern of red, round fruit. If you want to grow purple, orange, yellow, or striped tomatoes, you'll probably want to look for unique heirlooms. Determine what you want in a tomato and then find the variety that fits, whether its heirloom or hybrid.
3. "Days to Maturity" and "Days to Harvest" are important.
Seed packets or plant tags should give you an idea of how long it takes the plant to reach harvest. That is the number of days from the time you put the transplant in your garden, not the time from when the seed was placed in soil. Even a robust plant from a nursery can take more than two months to provide fruit. If you garden in a region with late springs and early falls, you may only have about four months to adequately grow tomatoes (my season is about 134 days). If you select an heirloom plant that takes 120 days to harvest, there will only be a few weeks for harvest before the first frost and if it's an indeterminate plant there will still be many unripe fruits on the vine when cold hits.
Match the plant with your garden for best results. A tomato that takes "80 days to harvest" can provide fruit for two months more than an heirloom beefsteak tomato. Of course, if you have a very long growing season your choices are virtually endless.
4. Tomatoes need sun and air.
Selecting the proper location for your tomatoes can make the difference between healthy plants and sickly ones. Tomatoes need full sun; that means at least 10 hours a day and more is better. Even a little afternoon shade can have a big impact on plant growth and harvest. Of all your garden plants, tomatoes should have the sunniest spot.
Many of the disease, virus, and fungal problems that plague tomatoes can be corrected by increasing airflow around the plants. Don't plant too close to other plants. With air circulation the leaves can dry out and not fall prey to the diseases that require moist conditions.
Tomatoes are a warm season plant and need warm soil and warm nights to begin growing. If planted too early, the plants can be stunted and even killed by cold soil temperatures. Some gardeners recommend planting when the air temperature remains above 50F degrees (10C), but that may be troublesome because the soil temperature at root level, six inches and more, can still be below that. Research has found that the best soil temperature is 70F; tomato roots will not grow at all below 50F.
I recommend waiting a few weeks after your last frost date to put in transplants. I also suggest using a temperature probe in your soil. Wait until the soil is closer to 60F to plant; at least 55F. You can accelerate soil warming by covering your garden bed with a plastic sheet for a few days before you plan to dig.
Tomatoes do best in amended soil. A well-drained soil is nice to avoid pooling water, but if the water drains too quickly the plant and fruit can suffer. Tomatoes will grow in clay soils as long as they don't remain soggy. The best way to correct poor soil is with organic amendments like compost. A loose, healthy, amended soil will grow bigger and better tomato plants.
7. Pinch off flowers and fruit when you plant.
Many gardeners select young plants with flowers or small fruit on them when looking for tomatoes in the belief they'll get fruit faster; nurseries grow and price them accordingly to entice you. You can actually delay the development of future fruit by choosing a too-mature plant for your garden.
The main role of the plant is to produce fruit and it will expend most of its energy to that task. However, for new transplants root development is the most important task. If you put a plant with flowers and fruit in your garden bed, root development will be reduced while the plant focuses on ripening the fruit. That means that your plant may not be strong enough to handle the heat of summer and all remaining fruit development can suffer. You'll get a better harvest if you let the plant grow strong in its early days
8. Bury the plant when planting.
Tomatoes can grow roots along the stem and you should use that ability to your advantage. More roots tend to make for a stronger plant. Placing the plant in the soil with more stem buried than in the original pot will ultimately provide better results.
Pinch off lower leaves next to the stem, leaving the top four to eight groups of leaves at the top. If you have amended soil in a region with steady rain, place the plant vertically in a deep hole with only the leaves above the surface. For poorer soil and in regions where your irrigation may be the only water source, place the plant in a slanted trench so that the stem is horizontal; you can gently bend the top towards vertical and hold it in place with a small soil berm.
Consistent moisture levels are more important than amount of water. Many gardeners think of tomatoes as tropical plants that need watering every day. Diseases, blossom end rot, and cracked skins can be the result of poor and inconsistent watering practices. Frequent, light watering can result in poor root systems.
Tomato soil should be moist all the time, but not wet or soggy; think of the moistness of a wrung-out sponge. With amended soil you may only need to water every three of four days. Of course, very hot and dry conditions will require more watering, but physically check the moisture level of the soil before assuming more is needed.
10. Overhead watering can encourage disease problems.
When you water, try to avoid sprinklers or hand watering from above. Almost all of the diseases that affect tomatoes are soil borne. The fungal spores and bacteria are just waiting for a way to reach low leaves and splashing water is the perfect mechanism. Even a drop of water falling from a lower leaf can release these tiny organisms from the soil surface and infect the plant.
Drip irrigation and soaker hoses can drastically reduce tomato diseases. These watering methods get water directly to the roots without any of the nasty side effects of overhead watering.
11. Mulch can help produce perfect fruit.
Mulching with a light, organic material can reduce the problems with soil and watering. Mulch helps to maintain a more consistent soil moisture level. Mulch also acts as a protective barrier so any water falling off the plant hits mulch and won't release soil-borne pathogens.
I like to use straw or herbicide-free grass clippings for tomato mulch. The light material allows air and water to reach the soil while helping to keep soil temperature and moisture more consistent. It will also decompose and amend the soil for the next season when I till it in at the end of the year.
12. Fertilizer may hurt your harvest.
Proper fertilization is critical to getting a harvest and improper fertilization may result in no harvest at all. With rich, amended soil you may not need any additional fertilizer. If you do fertilize, you need to do it differently at different times.
As mentioned above, root development is important for young plants. Adding a fertilizer high in phosphorus to the soil at planting can help in that development. As the plant grows and nears fruiting, a potassium fertilizer will help in fruit development.
The problem most gardeners encounter when fertilizing tomatoes is by using a fertilizer high in nitrogen. Nitrogen encourages big, bushy plant growth at the expense of flowers and fruit. If you fertilize and get a beautiful plant with no fruit, this is probably your problem.
Look for a fertilizer with higher numbers in the second and third position. The numbers on a bag or box of fertilizer represents the percentage of nitrogen-phosphorus-potassium (N-P-K). A higher first number will spell doom for your harvest. You'll find specialized tomato fertilizers with ratios of 3-4-6, or 5-6-5, or 4-7-10, or 18-18-21. Note that the first number (nitrogen) is never the highest. In my opinion, better tomato fertilizers would be 15-30-15, or 6-24-24, or 8-32-16.
13. Heat can reduce harvest.
If days and nights get too hot, tomatoes will drop blossoms and no fruit will form. Tomatoes grow best when the temperatures are between 70F and 90F degrees. When day temperatures are above 95F, or night temperatures remain above 75F, fruit won't develop. You can take every step above, but if it's too hot in your garden you won't get any tomatoes.
14. Pinching suckers may not always be the best idea.
Many gardening "experts" say to pinch off all suckers that develop in the crook between the main stem and branches. While this won't hurt the plant, it may not be as necessary as proposed. The key is knowing whether the plant is determinate or indeterminate.
Indeterminate tomato plants can get very big. Pinching the suckers can focus growth where you want it so the plant doesn't become too cumbersome while focusing plant energy for developing large fruit along main branches. Leaving the suckers on the plants will produce more foliage and potentially smaller fruit. Because the fruit is produced over a longer period, allowing it time and energy to grow big may be beneficial. Fewer, bigger fruits can be a good thing.
Determinate tomato plants don't require any pruning and removing suckers can actually reduce harvest. Tomatoes can develop on the branches that grow from the suckers. Because a determinate plant produces all of its fruit at the same time, more branches and more flowers means more fruit. For many gardeners wanting to preserve their tomatoes, more may be better than bigger.
15. Use a strong trellis.
There are many options for trellising tomatoes and it's worth spending the time and money for a sturdy one. While a single metal rod or flimsy wire cage will support a young plant, a mature indeterminate plant loaded with fruit will soon flop to the ground, damaging fruit and exposing the plant to all of those disease-causing soil pathogens.
I like to use heavy-gauge steel cattle panels to form a curved trellis over the entire bed. Home improvement centers sell steel lattice panels used for reinforcing concrete; these can be cut and bent into strong towers to support tomato plants. 4 x 4 wood posts set in the ground can be used to train vines on strong wire strung between them. Whatever you use, ensure it can handle the weight of a big plant.
As mentioned earlier, the pathogens affecting tomatoes reside in the soil. Once a plant is infected the soil is infected. Continuing to grow tomatoes in that same location the next year means that those new plants are very likely to be infected.
If your garden space allows, it is best to avoid planting tomatoes in the same bed as recent tomatoes. Time will dissipate the pathogens' viability. Wait at least three years between plantings in the same bed. Ideally, wait at least seven years between plantings. The more you can rotate with longer periods between, the less likely you are to encounter the same diseases.
17. Harvest before the fruit is overripe.
Tomatoes should be harvested when they're ripe but before they soften. Left too long on the vine, tomatoes can become mushy and bland. Green tomatoes can continue to ripen after they're picked. For that reason it's better to pick a little early rather than a little late.
The fruit may crack or develop circular rings near the stem when they've been left on the plant too long. Because the fruit often grows in clusters, you can use these signs on one fruit as a signal to harvest nearby fruit.
As indicated by these tips, tomatoes can be a finicky crop. A little too much water, a little too much heat, and a little too much fertilizer will affect your crop. I grow in a very challenging environment and I regularly meet gardeners unwilling to try tomatoes again after a disappointing season or two. It can be a challenge, but there's a reason tomatoes are the number one home garden crop. When you do it right, few other garden crops can be so satisfying.