The basics of growing tomatoes are relatively simple. Tomatoes like warmth, sun, and plenty of water. They can be grown in the ground and take well to containers, so they can be grown just about anywhere. It may look like work, but once you pop the first ripe fruit into your mouth you'll be hooked.
Most varieties will just sit there well after the last frost if the night temperature is less than 55 degrees. The more sun they get the more robust the plant, the more they'll flower, and of course those flowers are the source of the fruit.
Water well and deeply. Aim for uniformly moist, but not soggy, soil. It makes all the difference in how well your plants will do.
The following may help you with your plants:
Tomatoes are pretty tough and will grow in just about any type of soil. However, the richer the soil the more likely you will be able to raise beautiful tomatoes organically. Washed dairy compost is nutrient rich and won't burn young plants. It holds water well too, which is vital for tomato growth and happiness. Mulch to retain moisture with straw. Some folks like to add moisture granules to their soil and pots to retain moisture...especially when they might miss a day or two of watering.
Some tomato varieties are more susceptible to fungus, bacteria, and nematodes than others. And such vulnerability is usually compounded by your growing zone and soil type. Commercial varieties usually indicate on the tag, with a designation like VFN for example, if they are resistant to such systemic diseases as verticillium wilt, fusarium wilt, or nematodes.
If your tomato plants get sick and die quickly, the chances are good you have some type of systemic disease. If they lose all their leaves or leaves get curled, yellow, or just drop, it's more likely to be one of the many foliage diseases. Only a professional can diagnose the problem for sure. You may be able to diagnose the problem by contacting your county extension service or through a reliable nursery.
As with most things, an ounce of prevention is worth a pound of cure. Buy disease-resistant plants if you can. Heirlooms may not indicate any disease resistance, but that most likely means they haven't been lab tested for pathogens. Check some of the gardening message boards on the Web for tomato gardeners in your region; you may be able to determine which varieties are more resistant to prevalent diseases or problems in your area. Experience is also a good teacher, which is another reason for growing a several different types of tomatoes.
You can prevent foliage disease by keeping the leaves dry, which means watering at the base of the plants, not overhead. Also, a southeastern exposure is ideal because it is both warm without being hot, and the early morning sun dries dew so leaves don't remain damp for long. Also, but no less important, don't water your tomato plants at night unless you are using a drip irrigation system.
Space plants so they are well ventilated and not too crowded.
If you have too much to do in the garden and around the house, get help. For large home improvement projects a licensed contractor through ContractorNexus can help.