According to the University of Missouri, tomatoes are the most popular plant for home gardens. In my personal experience, there is not another vegetable that can beat the look or taste of a perfect, vine-ripened tomato. To get these luscious tomatoes, you first must prepare the soil in the garden. I've found that a well-prepared tomato bed will produce more, larger and better tasting tomatoes, as well as preventing nematode damage to the roots. Be sure to place your garden in a site that gets at least six to seven hours of full sun each day, or you'll be eating green tomatoes all summer off of spindly, sickly vines.
That All-Important Organic Matter
Tomatoes love well-draining, humus-rich soil. Unfortunately, they are also prone to damage by root-knot nematodes, so the more organic matter in the soil, the fewer nematodes. I always spread a 6-inch deep layer of compost or composted manure on the top of the soil and turn it into the soil well to a depth of 12 inches with a shovel, rake or garden tiller every year. You really can't have too much organic matter for tomatoes.
The Essential Soil Test
Soil testing is one thing many gardeners overlook, and it can make the difference between boom and bust in your tomato bed. Test your soil after adding organic material, as this can change the pH and nutrient value of the soil. Most local agricultural extension services will provide a soil test kit and do the testing free or for a minimal charge. Soil test kits can also be purchased at local garden centers or online. Follow the instructions for the soil test to the letter to get accurate results. This test should be done four to six weeks before planting, to give plenty of time to receive the results.
Soil pH and Micronutrients
Once you receive the soil test results, apply the soil amendments as directed. Tomatoes like a neutral to slightly acidic pH, so there will probably be instructions for adding lime or sulfur. If your soil is nutrient deficient, the test will recommend supplementation for that as well. Mix the amendments recommended into the top 12 inches of the soil with a turning fork. Smooth and level the soil with a garden rake.
Give Your Tomato Plants Room to Grow
Different varieties of tomatoes take different amounts of room. If you grew the tomatoes from seed, the package may have spacing requirements. If not, a general rule-of-thumb is 12 inches apart for dwarfs, 15 to 24 inches apart for staked plants, and 24 to 36 inches apart for trellised or ground bed plants. Vigorous growing indeterminates should be given 4 feet between plants and 5 to 6 feet between rows. In my experience, if you have extra room, spread them as far apart as possible and you'll get much more fruit.
Now you're all ready to put those tomatoes in the ground, knowing that they will be given the most beneficial soil conditions available. In a couple of months, you will be reaping the fruits of your labor and thanking yourself for taking the time to prepare the bed properly beforehand.
Personal Knowledge and Experience
University of Missouri Extension: Growing Home Garden Tomatoes