There’s no question that for many gardeners, tomatoes continue to be their favorite vegetable to grow. Unfortunately, even those of us who have plants loaded with fruit often wind up disappointed as the first killing frost of the fall arrives before the majority of fruit has ripened. With our current spring weather resembling last year’s unseasonably cold and wet growing season, here’s some time tested tips to get tomatoes to produce and ripen — even when heat units are lacking.
First, choose the right variety. WSU Master Gardener Emeritus Cindy Knight has conducted exhaustive tomato research trials at her home in Elma for more than 30 years to determine which varieties will do well in our cool, cloudy, coastal climate. According to Cindy, “Big Beef” has performed well in the large tomato category. For salad tomatoes, ‘Early Girl’ and “Early Cascade” are recommended. “Sugar Lump,” “Sweet Million” and “Yellow Pear”are the favored cherry tomato varieties. For paste tomatoes, both “San Marzano” which is resistant to the late blight fungus and “Roma” have done well, and for a tasty yellow tomato try “Lemon Boy’. Oregon State University has also introduced a number of tomato varieties that set fruit well under our cool coastal climate. They include: “Legend,” which is resistant to the late blight fungus and in Oregon produces the first ripe fruit in early July, “Gold Nugget,” a golden cherry tomato, “Saucy,” an early paste tomato, “Oregon Spring,” which produces incredibly early yields of 4-inch oval tomatoes and “Siletz” which is similar to “Oregon Spring” but with larger fruit and better flavor.
Second, when planting tomatoes, set plants deeper in the soil than they came in the pot. Tomatoes are unique since they are able to develop roots all along their stems. You can either dig the planting hole deeper, or dig a long, shallow trench, remove the lower leaves, and lay the stem down in the trench and cover with soil. Gently bend the top of the plant so the tip leaves are above the soil level. Roots will grow along the stem, providing a better root system early in the year.
Third, mulch the plants with a red plastic mulch. Now available in most retail nurseries and garden stores, the benefit of using red plastic mulch is that it reflects the far-right part of the light spectrum onto the tomato plant foliage. This, in turn, increases the production of the plant’s phytochromes which are color sensitive proteins that regulate plant growth and development. Researchers at the U.S. Department of Agriculture and Clemson University found that using red plastic mulch not only resulted in increased tomato yields, but also earlier harvest.
Fourth, increase the temperature of the micro-climate around your plants by using a floating row cover or water tubes. The advantage of water filled tubes, which are commonly sold as “Walls of Water” is that they collect heat during the day, releasing it at night. You can make your own inexpensive walls of water simply by filling used one gallon milk jugs or 2-liter soda pop bottles with water and completely circling your plants with them. Be sure to remove the water tubes before the plant becomes crowded inside.
Finally, there’s no hard and fast rule about leaving or taking off suckers from tomatoes. Many of the most popular tomato plants grown today are what are referred to as determinate or upright bushtype plants that need very little staking, pruning or sucker removal. If you grow some of the older indeterminate varieties like Early Girl, however, you may want to pinch out some of the suckers that originate between the main stem and main branch. Removing all of the suckers could potentially result in fewer fruit as well as sunburn to the fruit, so leave a few!
All too frequently, the home vegetable gardener will trim leaves from tomatoes and other vegetable plants, hoping that the fruit will ripen better if exposed to a greater amount of sunlight. Sufficient foliage must be present for photosynthesis to continue at the required rate. If the essential “food” is not manufactured as needed, normal fruit production will not exist. Cutting away an excessive amount of foliage destroys the process that produces the fruit. Removing a few leaves would be okay — just don’t overdo it!
Remember to water plants on a regular basis making sure to wet soil to a depth of eight inches. Irregular watering leads to blossom end rot and cracking of the fruit.
Donald D. Tapio is the Washington State University Extension regional specialist for Grays Harbor and Pacific counties. He can be reached at 482-2934 or firstname.lastname@example.org.