August 20, 2011

1 - Some tomato varieties do better in hot climates and some garden techniques help.

*Yard and Garden - August 20, 2011


Can you recommend an extremely heat tolerant tomato for the Carlsbad area for next year. Like most of my gardening friends I have big healthy plants with lots of flowers but very few tomatoes. I have read in our NMSU County Extension Agent's column that it needs to be below 74 degrees for tomatoes to set fruit. We have not had that since the monsoons have missed us this year. I am also curious if you think installing a misting system over my tomatoes and running it at night would be an effective way to get my tomatoes to set.

- Brad A.


In my experience, and from what I have read and heard, the smaller varieties of tomatoes (cherry, pear, and currant tomatoes) do best in high heat conditions. Many years ago, Texas A&M released 'Saladette' tomato (small Roma type) that was supposed to set fruit at higher temperatures. Recently the University of Florida released 'Solar Fire' to extend tomato production in the hot (and humid) summers of Florida. A list of tomatoes for Texas recommends the varieties 'Saladette', 'Carnival', 'Small Fry', 'Arkansas Traveler', and 'Heatwave II'. These are reported to set well in heat and drought conditions (remember Texas drought is not the same as the normally dry conditions of New Mexico). Heat will probably stop fruit set, but these may go further into the summer before the heat has its impact and may start bearing again earlier as temperatures finally begin to cool. They should produce good fall crops.

Some gardeners have begun shading their gardens to reduce temperatures and water loss. This will help maintain fruit set as temperatures climb and may also help avoid blossom end rot. There are many benefits to shading the garden in New Mexico - earlier planting dates, protection from early fall frosts, wind protection, water conservation, and a more pleasant gardening environment for the gardener. It also provides protection from hail! If you choose to build a shade structure for your garden, be sure to engineer a system capable of resisting New Mexico winds and tall enough to allow you to comfortably work below the shade material. Some gardeners use wooden snow fence as a shade material, other use shade fabrics. If you choose the shade fabric, look for a white or aluminized shade material. This will reflect surplus sunlight and diffuse sunlight that passes. Darker colored materials will be hotter below the shading material than light colored material. Look for materials that provide 30 to 50 percent shade.

Running a mist system at night will help lower the temperature, but will increase the water bill, may increase unwanted mineral salts in the garden soil, and will greatly increase the chances of fungal disease in the garden by raising night humidity levels. I would try shading the garden as a first resort and use mist only in very limited situations, or not at all.

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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