•When planting in the ground, you can place a large coffee can (opened on both ends) over the plant and push it halfway into the ground. When watering, fill the can to the top with water, which will then descend directly to the roots and allow the plant to flourish. Check for "suckers" (branches that grow in the joint between the main stem and other branches). There is a myth that suckers do not produce fruit; this is not true, but they do use some of the plant's nutrients as they grow. As a general rule, leaving suckers will produce more fruit, but smaller, while pinching them off will cause the plant to grow larger fruit, but less of it (because there will be fewer branches).
•If the stem or roots of the plant are damaged -- for example your toddler sits down on top of your 18 inch plant, snapping it near its base -- you can often save the plant anyway, by burying much of its above-ground stem and lower branches again, as you did to 75% of the plant when you first placed it in the ground. The little hairs on the stem and branches grow into roots. Since the plant is already in the ground, you accomplish this by piling dirt up around the plant, so that it grows out of a mound. Raised-earth growing is good for tomato plants at any time, because they are more vulnerable to certain ailments, especially fungus, when their hanging leaves and branches are in contact with the earth.
•You can get started earlier in the year by creating a temporary greenhouse. Make or buy cylindrical tomato cages made of heavy duty fence material. Use vinyl coated welded wire with a 3"x5" mesh, 5 ft. tall and about 1'6" in diameter. Plant the seedling and sink the cage into the dirt 4-6". Then take some sturdy, clear plastic (available in the garden center) and tape it securely to the cage. Moisture is retained and the plants are kept nice and warm. Remove the plastic when the plants emerge from the top of the cage or begin to form fruit, whichever happens first.
•Suckers that have been pinched off can also be rooted quite easily in moist soil to produce new tomato plants, but this practice does require a larger sucker, and is somewhat impractical in climates with a short growing season, since these plants will reach maturity later in the season and have less time to yield.
•In order to improve flavor, promote growth, increase harvest, and protect from insects, consider using companion plants with your tomatoes. Planting basil within 18 inches of your tomato plant, for example, improves the flavor of its fruit and repels many insect pests. Carrots increase fruit production, because the tomato plant draws nutrients from the carrots (which may grow smaller as a result). Basil also makes a wonderful addition to tomato-based dishes. Try adding it to your spaghetti sauce or bruschetta.
•Don't put too much water.
•Use manure tea for fertilizer. If you have access to well rotted manure, you can make your own fertilizer. Put the manure in pantyhose or cheese cloth. Place the "tea bag" in a 5 gallon bucket and fill the bucket with water. Allow the "tea" to steep for a few days. Dilute the tea 1:1 with water and give your plants a drink...They'll love it. If you're near the ocean, you can also use sea kelp for the same effect. Kelp is a good fertilizer for folliar feeding; spraying directly on the leaves, because it contains trace nutrients and hormones which are more easily absorbed through leaf pores, instead of indirectly through the roots.
•While you should avoid pouring too much coffee or fresh grounds into the soil for acidity, the very caffeine which makes this risky is also poisonous to slugs and other pests, which is why coffee plants evolved it. Even more effective than killing these pests is to simply spray the leaves of the plant with coffee. On the leaves, the caffeine is not concentrated enough to harm the plant, but is still enough to repel some pests.
•If you do decide to sucker (cut back) your "indeterminate" (not shrub type) tomato plants, consider not pinching off the whole sucker, but letting it grow just long enough to produce some leaves, then pinching off its tip. This will keep it from putting much effort into growing a long branch, but lets the first few leaves increase the surface area available to your plant for photosynthesis.
•Prior to setting your seedling in the ground, toss a couple handfuls of organic material in the bottom of your planting hole. As the roots grow deeper, they'll hit this layer of nutrients just in time to really boost your fruit output.