Ask a Master Gardener: The A to Z guide to growing tomatoes

Whether you grew them from seed or are going to buy plants, it's nearly time to get your tomatoes outside. Here are the basics for a successful crop of gardeners' favorite fruit.Choosing the tomatoIf you opt to buy plants, the first question to ask yourself is: Do you want all of them at the same time and be done with it or do you want tomatoes over a longer period of time? Determinate tomatoes produce all their crop over just 4 to 5 weeks, then they are finished for the season. They are more compact plants and produce fruit more quickly than indeterminate tomatoes.Indeterminate tomatoes grow and grow, producing fruit over a longer period of time. The plants are generally larger and set fruit from summer into fall. Because they are larger, they usually require some support like staking.The next question is: Which cultivar to plant? Details to consider include disease resistance, and personal preferences for taste, size, shape, and color. The University of Tennessee publication "THE TENNESSEE VEGETABLE GARDEN - GROWING TOMATOES" has a great table to help with deciding on which one to grow. It can be found at https://extension.tennessee.edu/publications/Documents/W346-H.pdf.Planting your tomatoesWait until the last predicted frost date to plant your tomatoes. This usually occurs around April 27 to May 10. Use a complete fertilizer two weeks before planting, such as a 10-10-10 product. You can either spread it evenly over the area or apply a band alongside the planting row. Work the fertilizer into the soil. Water the fertilizer into the soil well.Transplants should be 6 to 10 inches tall and hardened off. Make sure the hole for the plant is deep enough to accommodate the entire root ball. A soluble starter fertilizer can be added to the hole for both extra nutrition and moisture.Some type of support is often needed for the larger types of tomato plants. Cages and stakes are commonly used. Stakes should be made of a hard wood 4 to 5 feet tall for determinate tomatoes and 6 to 8 feet tall for indeterminate varieties. About 1 foot of the stake should be in the ground for the best stability. Use cloth or string to loosely tie the plant to the stake. Other materials could harm the stems.Wire cages need to be strong enough to support the tomato plants as they grow. They need to be well anchored into the ground and about 21 inches in diameter to accommodate the plant.WateringAn adequate and consistent water supply is vital to healthy tomatoes. They are thirsty plants. Generally, 1 to 1-1/2 inches of water per week is needed. In very hot or dry weather, more water may be needed. It is also recommended to water half the weekly amount twice a week to provide more consistent moisture and reduce runoff. Consistent water also helps to prevent blossom rot. If using sprinklers, make sure there is enough time for the leaves to dry before nightfall to avoid disease.PruningIndeterminate tomatoes produce lateral branches, often referred to as suckers. Removing suckers ensures more nutrition is available to grow a good crop of tomatoes. However, lateral branches can also produce fruit. Often, cage-grown tomatoes are not pruned to take advantage of the extra crop.Determinate types of tomatoes do not necessarily require pruning. Because they grow only to a certain height and produce all of their fruit in a short period of time, it may be advantageous to leave the lateral branches for a higher crop yield.Fertilizing during the growing seasonTomatoes are hungry and require quite a bit of fertilizer not only when planted but also during the growing season to promote good fruit production. After the first fertilizer application at planting time, two more are recommended as side-dressings with nitrogen and potassium being the most needed supplements. Do the first side-dressing when the first fruits form. The second side-dressing may be needed depending on soil fertility, growth rate and fruit production. Avoid disturbing the roots and keep the fertilizer 6 to 8 inches away from the plants to prevent burning the roots and stems.Many resources warn against using Epsom salts (magnesium sulfate) unless a soil test indicates a deficiency.Here's looking forward to a tasty crop of your home-grown tomatoes!Resources"The Tennessee Garden – Growing Tomatoes," https://extension.tennessee.edu/publications/Documents/W346-H.pdf"Growing Vegetables – Tomatoes," https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource000609_Rep631.pdf"Growing Tomatoes in a Home Garden," https://extension.umd.edu/resource/growing-tomatoes-home-garden