This column is written by the Master Gardeners of Yolo County each month. It provides answers to selected questions recently asked by Yolo County gardeners.
Question: I would like to plant tomatoes in my garden this year. What tips do you have? What varieties should I try?
Answer: Growing tomatoes in your own garden can be very rewarding. Our long sunny summers and warm evenings create excellent conditions for tomatoes. And while it can sometimes be too hot for tomatoes as well as for people, there are ways to minimize the negative impacts. With some attention to timing, soil preparation, care, and choosing varieties suited to our climate, you should be able to grow a good crop of vine-ripened tomatoes.
Once the rain stops and the soil has dried out enough, you can begin by adding a couple of inches of compost to your bed and working it in. If you are using an organic tomato and vegetable fertilizer, that is a good time to work it in, as directed on the package. As an organic fertilizer, it will need some time for the soil bacteria to break it down.
If you are starting plants from seed, early March is a good time to plant. Grow them inside under lights for the best results.
If you buy starts from a nursery, know that they usually show up earlier in the stores than they should be planted out. Tomatoes planted when the soil is still cold and the nights are cool will grow slowly and may not fully recover. If you have a soil thermometer, wait until the soil is consistently sixty degrees and nighttime temperatures stay above fifty degrees. Another often reported technique is to wait until you can comfortably sit on bare ground in your underwear for thirty minutes. Let us know how that works for you if you try it. If you want to simply go by the calendar, those conditions usually occur in mid to late April. If you buy your tomatoes earlier, you can plant them in one-gallon pots while you wait.
Tomatoes should be planted where they will get at least six hours of sun per day; more is better. Some afternoon shade is ok and can be beneficial. When transplanting, bury plants deeper than they were in their pots; tomatoes grow roots along buried stems, making them stronger. Leave at least three feet between plants. Indeterminate (vining) varieties especially benefit from cages, stakes, or trellis. Try to rotate your tomatoes to leave three years between planting them and their family members, peppers, eggplant, and potatoes, in the same place.
Water deeply and regularly once plants are established. Avoid wetting foliage to reduce disease. You should only water one time per week, approximately five gallons for a full-sized plant. If it is particularly hot, approaching one hundred degrees, or if you have sandy soil, an additional day of watering, adding two to three gallons, may be necessary. A layer of mulch (straw, shredded leaves, wood chips) helps conserve soil moisture and reduce weeds. When temperatures climb above ninety degrees, tomatoes can struggle to set fruit. Erecting a structure for shade cloth on the west side to provide afternoon shade can help.
Dozens of varieties can be successful in our area. But not all are created equal. Many large varieties, especially heirlooms, do not do well in our heat. We recommend that you concentrate on those proven to do well here and then add one or two “experiments” if you want. Cherry tomatoes tend to be the most successful and earliest ripening, so one or two should be tried. Other than that, medium-sized tomatoes do better than large “beef steak” types. Another consideration is resistance to nematodes and soil-borne disease, which is typically found only in hybrids.
Here is a list to start with: cherry tomatoes- Sungold, Sun Sugar, Sweet 100 and Juliet (a grape tomato), medium-sized tomatoes- Early Girl, Celebrity, Lemon Boy, Berkeley Tie Dye, larger tomatoes: Hawaiian Pineapple, Costoluto Genevese, and, suggested by Don Shor at Redwood Barn Nursery, Cosmic Burst, Carmello and Genuwine.
With a bit of planning and care, our long, warm growing season can yield tomatoes from early summer into fall. The right timing and varieties will make your garden a success.
Have a gardening question? Send it to jmbaumbach@ucanr.edu, with “Ask MGs” in the subject line. Include as much detail as possible and pictures if you have them.