Tending Your Tomato Plants
Once you've determined that you're going to grow tomatoes in your garden and you've figured out the optimal time to plant, it's time to make sure your plants thrive and produce high yields and lots of fruit.
A common problem growing tomatoes is not giving tomato plants enough space to grow. When they are seeds or seedlings, it is hard to imagine how large they will get. They need lots of space to spread out. If they are not given enough space, their vines will intertwine and you will end up with a tomato jungle.
This is especially true of indeterminate tomato types, which can easily grow 5-6 feet tall and spread out just as wide. They may even need more spacing then the recommended amount to give comfortable space to move between plants at harvesting.
If you are planting from seed, place them 1/2” (1.27 cm) deep in groups of 4-6 seeds, 25 inches (63 cm) apart in rows spread 28 inches (71 cm) apart. When the plants have grown to three leaves, thin out to 1-2 seedlings per group.
If you are planting from transplants, put plants 2 feet (61 cm) apart in rows that are also 2-3 feet (61-90 cm) apart. If your plants are leggy or tall, they can be planted deeper as tomatoes form more roots from their stem. Do not transplant plants that have already begun to flower or fruit; they will grow slowly and yield poorly.
It is hard to say how much fertilizing is necessary, as each garden has it's own unique soil and needs. To understand best what your tomatoes need, you should get your soil tested.
Tomatoes are heavy feeders, which means they will eat up any fertilizer you add. This can be good, if the tomatoes are in need of what you are adding. If they don't need it, and they are getting excessive nutrients, especially nitrogen, you will see your tomato foliage grow large and lush, and delays in fruit production.
Four to eight weeks after transplanting your tomatoes, you can side dress the plants with nitrogen (21-0-0), adding ½ tablespoon per plant. Side-dressing means applying the fertilizer 2-4 inches beside the row, never letting it touch the actual plant. The fertilizer will then need to be watered so it will be absorbed into the soil.
Tomatoes need frequent regular watering. If you can plant them with easy access to a water source, that is best. They need approximately 1-1.5 inches of added water in a week, preferably in the morning. Watering in the evening causes the roots to stay wet longer and therefore encourages diseases to take hold. Only the tomato plants roots should be watered, not the leaves. If the leaves get too wet, or stay wet, it can also encourage diseases.
Drip irrigation works best. It is also best to irrigate so the water seeps deep down to the plants roots. During dry spells, they will need watering 3-4 times a week. Uneven watering (too much, or too little), can cause blossom end rot, a dark brown spot on the bottom of the fruit.
When tomato plants receive too much water after a dry spell, the skins may crack or split. Fruit cracking can also occur when ripening if the fruits absorb too much water because of rain or overhead watering.
When the tomato plants have become established, you should apply mulch around them to control weeds and also to keep moisture in. After the soil has warmed up to 75F, you can apply organic mulches, like grass clippings, straw or leaves. If you apply the mulch too early, the soil will stay cold and affect the plants root growth.
Another mulching option is black plastic. This can be set up before you transplant your tomatoes by cutting or punching holes in the plastic to fit over the plants. The benefits of black plastic are that it can warm up the soil, prevent weeds, and retain soil moisture.
To keep ripening fruit from touching the ground, it is good to use a type of trellis system, wire tomato cages or wooden stakes. Supported plants will be healthier and have a higher fruit yield. Plants will also be easier to harvest when they are supported.
If you decide to use stakes, they should be at least 8 ft (2.5 meters) tall. They need to be driven at least a foot (30 cm) into the soil, about 3-4 inches (7.5-10 cm) from the plant, to provide adequate support and so they don't get blown or tipped over in a storm. As the plant grows, suckers, or laterals, that grow out the side will need to be pruned as they will compete with the fruit for nutrients and cause a smaller yield.
Wire cages can be purchased at garden supply stores. These cages are round and fit around the tomato plant, supporting it on all sides. They need to be set up while the plant is still young otherwise it will be hard to fit it around all the stems and leaves.
Indeterminate type tomato plants need lots of support and will benefit from being regularly pruned and tied up to the stakes or trellis as they grow.
Tomatoes should be picked as they ripen, when they are firm and fully colored for the best flavor and quality. From the time the plants flower to when the fruit is ripe, is around 40-50 days, depending on the variety.
Ripe tomatoes can be stored for 1-2 weeks if kept at 50-55°F (10-12.7°C). They should not be stored in the refrigerator unless absolutely necessary. Refrigeration can cause the fruit to lose flavor and turn mushy. When the season ends, pick all the fruit, ripe and green, setting out unripe fruit to ripen.
For addiitional accurate growing instructions read more on how to grow tomatoes.
Utah State University, Cooperative Extension, Tomatoes in the Garden
Ohio State University Extension, Growing Tomatoes in the Home Garden