March 8, 2014

1 - A soil test is the best way to know how to prepare garden soil, but addition of compost is usually beneficial.

Yard and Garden March 8, 2014


I want to plant tomatoes in a flower bed that is 2'x20'. What kind of soil is best for tomatoes? What variety of tomatoes is best for this area? Is there any certain kind of fertilizer that is required? About how many plants could I put in this space?


You should be able to grow tomatoes in the area you described based on the size of the area and room for roots. A good soil test will help you to prepare your soil for tomatoes. Your local NMSU Cooperative Extension Service office can help you find a soil testing laboratory and help you interpret the results when you receive them. You may still have time in your area to have your soil tested, but time is running out. You will want the results in time to add any needed nutrients and amendments to the soil before planting the tomatoes.

In case you are not able to have your soil tested this year, here is some basic information. In general the tomatoes prefer a well-drained soil with a lot of organic matter. This organic matter can be provided in the form of compost. It is a little late to use manure since that should be applied in the fall in hopes that excess salts common in manure will be leached away by winter precipitation. The organic matter in the soil helps hold and release nutrients to the plants as well as maintaining a more constant soil moisture level. If your soil has a high level of clay or sand, compost can greatly improve the characteristics of your soil and the growth of plants in that soil.

Without knowledge of the nutrients already in your soil, it is difficult to tell you how to fertilize. Once again, here are some general ideas for home gardeners: Young rapidly growing tomatoes benefit from nitrogen fertilizer, but as the plants mature and should begin flowering they need higher levels of phosphorus in the soil. Some gardeners give young plants a jump start with manure or compost tea or diluted nitrogen fertilizer. As the plants mature, the gardeners side-dress with phosphate fertilizer to stimulate flowering and fruit development. If the plants have too much nitrogen during the fruiting season you may observe beautiful vines that produce few or no tomato fruits.

A final consideration is the exposure of your garden spot. If it receives afternoon sun and is exposed to frequent drying winds, the tomatoes may not perform well for you. Some shade (whether constructed or grown in the form of corn and other tall plants) will help avoid problems.

Varieties of tomatoes known to produce well in New Mexico are listed in NMSU Extension Circular 457-B: Growing Zones, Recommended Crop Varieties, and Planting and Harvesting Information for Home Vegetable Gardens in New Mexico. This is available online at Circular-457B: Growing Zones, Recommended Crop Varieties, and Planting and Harvesting Information for Home Vegetable Gardens in New Mexico. Many other useful publications are available at the NMSU publications site: ACES Publications. Your local NMSU Extension Service office can also provide information about varieties of tomatoes that do well in your area. The number of plants you can grow in the area you described depends on which varieties you choose. In general they should be spaced 2 to 3 feet apart, but some smaller varieties may be planted more closely.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email:, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

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Please copy your County Extension Agent and indicate your county of residence when you submit your question!