by Dr. Bob Randall
Every June since its inception, I have appeared at the Urban Harvest Tomato Fest to answer questions about growing tomatoes. We also rejoice in and taste the wonderful bounty this most popular fruit vegetable offers us. I get a lot of questions every year because the challenges of growing tomatoes successfully are widespread for beginners, but not that hard to overcome if you know how.
Here I’ll try to answer three common questions:
Q. I have lots of flowers on my tomatoes but no fruit. What’s wrong?
Answer: Timing & Varieties. Your flowers aren’t pollinating because the pollen is sterile when daytime temperatures are over 85˚F or night temperatures are above 70˚. In most of Southeast Texas there are 4-6 weeks in the spring when temperatures are over 50˚F and below the maximums for pollination. So, your plants need to be full of flowers during these weeks. Once the flowers set fruit, they will ripen even if temperatures are hotter, so the tomatoes you eat in summer set fruit in cooler temperatures.
In spring, depending on your location, proper temperatures for pollination fall between late March and early May. In the fall, in areas that don’t get November or early December freezes or if you use plastic hoop-houses, cherry tomatoes will often set fruit from late September to early October.
There are several things you need to do to get this timing right. First, it is much easier to get early flowers on so-called early season or mid-season tomatoes, than it is to get early flowers on so-called late varieties. Also, there are more flowers on cherry tomatoes than there are on beefsteaks, and more flowers on so-called indeterminate tomatoes (that keep on fruiting up the stem) than on determinate ones that fruit all at once. Good early season varieties include the yellow hybrid cherry Sungold and the non-hybrid heirloom red plum tomato Bloody Butcher. Many mid-season varieties work also.
My recommendation is to figure out when in the spring you regularly have these temperatures. Six weeks before the start of these temperatures, put cold protected transplants in the ground. And 4-6 weeks before that start seeds in a room or greenhouse at 60-80˚ temperatures. In the southern part of Houston, I start seeds indoors under lights the first week of January and put highly temperature protected transplants outside the second week of February. Your dates may differ if you are further from the Gulf or closer to it than me, or if you are more urban or less so.
Q. Leaf-footed stinkbugs are wrecking my tomatoes. What can I do?
Answer: Trap them. Generally, organic gardeners don’t turn to poisons to solve pest problems. Rather, we ask, “Why doesn’t the pest have a pest?” and do what we can to welcome pest predators and parasitoids. But in this case neither poisons nor predators works well, so our victims are our tomatoes and us.
What you can do is plant asparagus beans (long beans or yard-long beans) on a six foot trellis this month and pick the bugs off the beans about 8 a.m. in August. On long beans, they are easy to catch and dispatch by sticking them in soapy water. They have relatively low reproduction rates, so if you work at it for a while, the numbers next spring will be small.
Q. I’ve got so many other questions…
Answer: See you soon. I’ll be at the Urban Harvest Tomato Fest June 15th, so come by, and I’ll do my best. I am also co-teaching a Fall Organic Vegetables class July 20 for Urban Harvest and a 10-class course next January. My new book will be out this summer.