2019 ASHS Annual Conference

Whether growing in a large container on the patio or a row in the home vegetable garden, tomatoes are one of the most popular vegetables in the world, but growing tomatoes in the Mojave Desert is not easy. Heat, low humidity, salty infertile soil and intense sunlight all conspire to foil the home gardener. The choices for Mojave gardeners were either to let the plants die back around June, when weather conditions became extreme, or cut them back at that time, and water through the summer in the hope they revived when temperatures were again in the double digits. Cooperative Extension in southern Nevada has been recommending shading plants in the summer to extend the season, and help improve production as well as quality. The question remained “Does shading up tomatoes really help in a harsh desert climate, and if so, how much shade? Do all tomato cultivars benefit equally?”

We selected four commonly grown tomato cultivars for the experiment: Celebrity, Early girl, Heat Wave and Red Cherry. The treatments were, 0%, 30% and 50% shade. We transplanted seedlings into raised beds with organically amended soils. The land where the raised beds were located where plants had not grown previously. Major problems included wind damage, sunscald, herbivory and root knot nematodes. The project had some noticeable results, indicating that 30% shade gave the best yields. In the 50% shade treatment, the plants grew very large, but had few blossoms or fruit. The high standard deviation made the results not statistically significant. Despite the problems, the data is not useless, and will give guidance to growers. It indicates that we need at least another year of testing.