Can I Use Miracle-Gro With My Tomato Plants?

When you plant your first vegetable garden, you'll no doubt consider planting a tomato (Lycopersicon esculentum) or two. Once you've navigated through the wealth of heirloom and hybrid varieties, you will want to consider nutrition for these greedy vines and shrubs so they can produce the maximum number of juicy globes. Scott's Miracle-Gro makes a soluble fertilizer marketed specifically for these nutrition-packed fruits.

Tomatoes are tender perennials, hardy only in U.S. Department of Agriculture plant hardiness zones 10 through 11, that are grown as annuals in vegetable gardens. Older cultivars, known as heirloom varieties, grow in a profusion of sizes, shapes and colors. Newer hybrids are more uniform in shape and red or yellow coloration. They are bred to resist a variety of blights that afflict the crop. Heirloom tomatoes typically perform best in areas where they were developed, but hybrids tend to produce equally well in all areas, providing the growing seasons are equal.

Growing as vines or compact shrubs, tomatoes grow from seedling to producing ripe fruit in from 70 to 90 days, depending on variety. Such rapid growth requires nitrogen, but once it's time to produce fruit, more nitrogen retards blooming by forcing more foliage growth.

What's needed for flowering and the fruit that follows is plenty of phosphorus and potassium. Several minor nutrients are also necessary to ensure the development of lycopene, vitamin A and vitamin C in the fruit. The University of Missouri Extension suggests a formula of 8-32-16 -- four times as much phosphorus and twice as much potassium as nitrogen -- or 6-24-24 with even measures of phosphorus and potassium.

Miracle-Gro's vegetable plant food comes in a box that prominently features a picture of a tomato and boasts an N-P-K ratio of 18-18-21. While this may be preferable to Miracle-Gro's All-Purpose fertilizer, which is rated at 24-8-16, it seems to carry more nitrogen than recommended.

Miracle-Gro recommends mixing 1 tablespoon of fertilizer to 1 gallon of water for each plant and watering in every seven to 14 days. Miracle-Gro recommends a half-strength mixture -- 1/2 tablespoon of fertilizer in 1 gallon of water -- for plants in containers. The manufacturer encloses a convenient two-ended spoon with appropriate measures.

The high percentage of nitrogen in Miracle-Gro's tomato food might benefit tomato plants as they grow to maturity. Once the first yellow flowers bloom, however, be on the lookout for dark green foliage growing at the expense of flowers and poor fruit development.

If your plants display these symptoms of nitrogen overdose, stop fertilizing. If plants have further trouble blooming and fruiting, resume using the Miracle-Gro tomato food on a less frequent basis or find a garden fertilizer with higher percentages of phosphorus and potassium.