Tomato plants are one of the most popular home garden crops. Even though tomatoes are fairly easy to grow, the plants require adequate nutrients to remain disease resistant and produce healthy and tasty fruit. Nutrient deficiencies are seen as different symptoms on the tomato plant. Planting tomatoes at the appropriate time of year and fertilizing plants throughout the growing season help plants stay healthy and produce fruit.
Tomatoes require a broad range of nutrients, as do most plants. Some of the more common deficiencies affecting plant growth and fruit quality are phosphorus, nitrogen, calcium, potassium and boron. Each of these nutrients contributes to some facet of plant growth or fruit production.
Plants with insufficient phosphorus will be stunted, and they will have few flowers and fruit. If you look at the leaves of a phosphorus-deficient tomato plant you will see purple veins. Calcium deficiencies contribute to blossom-end rot, a problem that destroys tomato fruit. Blossom-end rot starts as a brown spot at the bottom of the tomato, which spreads until it consumes almost half the fruit. Fruits with blossom-end rot should be removed from the plant and discarded. Too little nitrogen also stunts plant growth, but too much nitrogen makes the plant produce vegetation rather than fruit. Potassium deficiencies result in poor fruit quality. If the soil lacks boron, plant stems will be brittle and there will be problems with fruit quality as well.
Nutrient deficiencies can occur at any time during the growing season. Cooler temperatures early in the growing season can inhibit phosphorus absorption. Rapidly growing plants use nutrients quickly, especially as they transition to fruit production instead of foliage growth. Plants need potassium to produce healthy fruit, but require nitrogen for healthy foliage.
Prepare soil before transplanting tomato seedlings to get plants off to a healthy start. Working an organic compost into the top 2 to 3 inches of soil will help provide an ample supply of nutrients to help the plant grow. Even adequately prepared soil will need to be fertilized and supplemented throughout the growing season to maintain healthy tomato plants and good-tasting fruit. Plan to side-dress fertilize tomato plants weekly once fruit sets. To help warm the soil in the early part of the growing season, use a dark plastic mulch. Not only will it warm the soil and help phosphorus absorption, but it will reduce the likelihood that fungal spores will be transferred to the plants in wet weather.
Providing proper nutrition to your tomato plants will help them to stay healthy and increase tomato harvests. If you are uncertain of your soil's composition, contact your county extension office or consider having your soil tested. Well-nourished plants are more resistant to disease and pests.