Where you plant your tomatoes
in the garden is important. Tomatoes need at least six to eight hours of sun a day to produce well -- and full sun is best, especially in cooler, more northern climates. Tomato roots won't do well in soggy soil -- a sunny, well-drained part of your garden is best.
Best Soil for Tomatoes
Tomatoes like their soil pH around 6.0 to 6.8. Briefly, pH is a measure of soil acidity or alkalinity. On the pH scale, 7.0 is neutral; so the range which tomatoes prefer is slightly on the acid side. (By the way, that's the pH range at which most vegetables grow best.)
You should check the pH level in your garden every three to five years. You can test it with an inexpensive kit from a garden center, or your local cooperative extension service may offer an inexpensive testing service.
If your soil pH is too low (too acid), you'll need to add lime to the soil to bring the pH back into the proper range. Gardeners in western states (and some areas of the east) often have high pH or alkaline soils and may need to add sulfur to the soil to lower the pH. Although lime and sulfur can be added to the soil any time the ground isn't frozen, fall is a convenient time for many gardeners and gives slow-acting lime a chance to take effect. Get recommendations from the Extension service on how much lime or sulfur to apply based on your soil test report.
Making Better Soil
No matter what kind of soil you have in your garden, you can shape it into a great home for your tomatoes with a little work. Both light, sandy soils that drain too rapidly and heavy, clay soils that take forever to drain and warm up in spring can be improved with the addition of organic matter -- leaves, compost, grass clippings, garden residues or easy-to-grow cover crops such as buckwheat
or annual ryegrass.
In sandy soils, organic matter builds up the soil's water-holding capacity. This is vitally important for tomatoes, which depend on a continuous supply of moisture all season long. But tomatoes don't want to sit in puddles! Organic matter also opens up heavy soil so that water and air penetrate better.
If your tomato crop has been only so-so for the past few years, work some extra organic matter into the soil where your plants will be growing. You'll probably see a big difference in the harvest.
Before transplanting tomatoes, it's a good idea to work the soil until it's loose to a depth of six to eight inches. You can do the work with a tiller or a garden fork. The tomato roots will be able to expand quickly in the loose earth and you'll also uproot and kill many weeds.
It's important to work some fertilizer into the soil at transplanting time, so that your transplants can get off to a good start.
After the soil has been well tilled and is loose, make a trench or furrow six to eight inches deep down what will be the row of tomatoes. At the bottom of the furrow put a thin band of organic or chemical commercial fertilizer, such as 5-10-10. The numbers 5-10-10 refer to the percentages, by weight, of nitrogen (N), phosphorus (P) and potassium (K) in the bag of fertilizer. They'll always be listed in that order, too: N-P-K.
Another method is to put down a deeper band of dehydrated animal manure, compost or rotted leaves. You can use both methods for a quick start and strong finish for your tomatoes.
Then, no matter which method you've chosen, cover all this fertilizer with two or three inches of soil. If your transplants' roots or stems come in direct contact with the fertilizer, the salts in the fertilizer can draw moisture from them, which is harmful. If the fertilizer is deep underneath the plant, the roots will grow to it and absorb the nutrients gradually.
After covering the fertilizer, it's just a matter of transplanting the tomatoes into the 3- to 4-inch-deep furrow.