Successfully Grow Tomatoes in the Desert

Q. I raised tomatoes for about 7 years and this year was my best year. The tomatoes that work best for me are Early Girl, Champion and Celebrity. This year I got about 200 tomatoes from these three plants already, they are still coming, and they taste good too. The only thing I did differently this year is put a 1-inch layer of worm castings on top of the soil. Was it the weather or the worm castings that did it or both?

Worm castings is now a popular addition to raised beds for vegetable production.. Photograph complements of Viragrow, Inc. Las Vegas, Nevada.

A. This may sound like heresy but there is nothing special about the fruit when using worm castings versus any good compost or quality amendment added to the soil. Some may argue but the tomato plant doesn’t know the difference. The important thing is that soil improvement was done. 

But the overriding factor this year was probably the cool spring weather. Granted, you are managing your tomatoes better each year, the spring weather was cool for a long period of time, and you applied a good soil amendment and fertilizer in the form of worm castings.

I think this is what everyone wants to accomplish when growing tomatoes, a high quality tomato that tastes good. This tomato was grown in Balkh Province, Afghanistan, where temperatures can rival the Las Vegas area. If they can do it, you can do it.

            Repeat what you did next year and see if there is a difference in your production and the taste of your tomatoes. Hopefully, you took some good notes. I am guessing you will see a smaller number of fruit produced if the weather heats up in a hurry and there isn’t a long, cool spring like we had this year. And if you use a good soil amendment, like worm castings or a quality compost, the tomatoes should taste superb again.

The Zimbabwe "Worm Man" who was selling worm castings that he was producing. Although the plants don't know the difference, there is some scientific research that demonstrates some benefits to plants when using it.

            Tomatoes stop setting fruit when air temperatures stay consistently above 95F. The tomatoes that set earlier continue to grow and mature when it stays hot. That isn’t the problem, It’s the production of fruit that stops at high air temperatures. That’s when the entire plant stops making more fruit.

If you don't have much room a tomato plant can be grown in a nursery container. I would recommend using a 15 gallon nursery container. When you are finished with production, this composted soil can be added to the garden or landscape. It makes crop rotation easy. Just replace the soil and container! Photo courtesy Viragrow, Inc. North Las Vegas.

            If the air temperature drops below 95F for a couple of days, new flowers will again set fruit. They stop setting again once the air temperature returns above 95F. With air temperatures that fluctuate to the low nineties and then rise to the high nineties, tomato fruit production may be erratic.

Fertilize tomatoes with a start up fertilizer at the beginning and don't fertilize again until you start to see small fruits develop from the flowers.

             Some other varieties of tomatoes to try include cherry tomatoes like Sweet 100, Sun Gold and grape tomatoes as well as the yellow pear tomatoes. These plants are reliable, quickly produce fruit from flowers and can fill some gaps when temperatures fluctuate a lot.

Yellow parrot tomatoes, along with great tomatoes and cherry tomatoes are always successful in our climate. They don't require a lot of production time from flowering to finish. Throw in a couple of these tomato plants with your others to help fill in the voids in production.

            Also, choose tomatoes that are determinate in form rather than indeterminate. These tomatoes tend to produce larger numbers of fruit early in the season and don’t sprawl all over the garden.

Pretty good information on determinate versus indeterminate

            Include varieties like Better Boy or Big Boy and a Roma type like San Marzano for a “meatier” tomato. Move tomato plants to the other end of a raised bed rather than plant them in the same spot year after year. This helps reduce disease problems.

Pretty good information on crop rotation

            High temperatures produce a sweeter tomato and lower temperatures keep the acidity higher. Good flavor needs a balance between sweetness and acidity. The variety and weather conditions produce these delicate flavors unless the soil is void of plant nutrients.  Small amounts of mineral fertilizers work well if the soil has organics, like worm castings, added to it.

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