1 - Splitting tomato fruit is a common problem in gardens, but there are some things you can do to reduce the incidence of split fruit.

Q.
I grew tomatoes last year in my home garden in Lea County. The plants grew fine, but the fruits cracked. How do I keep them from splitting on the vine? They were terrific eating; I just cut around the splits.

- Dennis H.

Via NMSU, University-Wide Extension

A.

Tomato fruits often exhibit cracking when their skins loose elasticity and then the fruit receive water and enlarge. The loss of elasticity of the fruit skins is most common as the fruit are nearing maturity. This problem occurs in other states as well as in New Mexico and is often attributed to failure to irrigate properly to maintain consistent moisture in the soil. During dry periods the growth rates of tomato fruit slows and the skins become less elastic. When the plants are irrigated after the plants have dried, even if they dried only a little bit, the fruits absorb water, begin to enlarge, and in some varieties the skins are unable to stretch enough to accommodate the enlargement. The environment in New Mexico can make this situation more complicated. Even when there is adequate irrigation, drying winds and intense sunlight in New Mexico can result in water deficits within the plant while there may be adequate moisture in the soil.

Some varieties are more resistant to fruit cracking than other varieties. Larger fruited varieties may be the most susceptible and smaller fruited varieties may be more resistant. This is a generalization and may not be correct for all varieties. Gardeners should grow several varieties when possible, each year noting which varieties perform best and which have problems. Look for varieties that are reported to resist fruit cracking.

New Mexico gardeners should use techniques that gardeners all over the country use to maintain adequate soil moisture. We should irrigate often enough to prevent soil drying. We should use mulch to conserve soil moisture and maintain uniform soil temperatures. Both plastic mulch and organic mulches will benefit tomato plants and reduce the incidence of fruit cracking. We do little to control moisture from precipitation, but we can irrigate to prevent drying of the soil. We should also irrigate in a manner that avoids creating waterlogged soil.

In New Mexico, our intense sunlight and drying wind based problems may be managed to some degree by growing plants where they receive some shade during the hottest part of the day and in locations where the plants are protected from winds. This may be managed by carefully choosing tomato growing locations in relation to structures, or by employing other garden plants to provide shade and wind protection. Tomato plant planted among corn plants will receive some shading and wind protection from the corn plants. Rows of climbing plants or self-supporting tall plants may be planted upwind of the tomato plants.

Finally, careful application of nutrients can help tomato plants reduce the incidence of fruit splitting. Nitrogen application will stimulate vegetative growth that competes with the developing fruit for water. Phosphorus applications will stimulate flowering and fruiting. Potassium is important for water management and efficient plant use of water. The proper balance of nutrients, especially the "macro nutrients" listed above, and many other nutrients, results in better plant health and fruit production. Soil samples sent to professional soil testing laboratories can help determine the status of soil nutrients in your garden and determine the need for nutrient application. Your local NMSU Cooperative Extension Service can advise you regarding soil testing and interpreting the results of soil tests.

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: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

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

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

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