If your tomato plant was slow to produce this year, you were not alone.

The odd cool wet weather we had delayed or discouraged tomato flowering. I’ve heard a few comments about it and observed it on my own plants this year, too.

Tomato pollination is tricky. They are wind-pollinated, not insect pollinated. The flower must be shaken so that the pollen grains can fall onto the female stigma. If the humidity is less than 40% or greater than 70%, the tomato pollen grains will stick and won’t shake down. Temperatures at night above 70-75 degrees Fahrenheit and day temperatures above 85-95 degrees Fahrenheit make pollen grains sticky, too.

Other causes of no tomato set include nutritional diseases, too much nitrogen fertilizer, and excessive water stress. Now that our weather has switched to more typical July weather, you should be seeing more new little tomatoes. That is, until it gets too hot.

Tomato plants were slow to start setting tomatoes in our homeowner tomato trial too. The goal of this trial is to find out which varieties are the easiest to grow and the most productive. I especially want to find out which varieties will continue to produce, even when the weather gets too hot.

In the trial, every participant is given a Celebrity variety tomato plant, because it’s the most consistent producer for our area. Last year in mid-June 2020, 82% of the Celebrity plants given out were reported as flowering, with 61% of them reported to have dime-sized tomato fruits. Around the first of June 2021 this year, 90% of Celebrity plants were reported as flowering, but only 27% were reported to have new dimesized tomatoes.

While the plants may have set a few tomatoes earlier, they weren’t setting many in early June this year. So it wasn’t your imagination, many people were seeing fewer little tomatoes on their plants during the prime growing season. June had some cool moist days too, but by early July when participants were surveyed again, 88% of all Celebrity plants in the experiment had produced at least one tomato.

In addition to Celebrity, other tomatoes in this year’s trial include Abe Lincoln, Atkinson, Bella Rosa, Big Beef, Cherokee Purple, Purple Calabash, Red Snapper and Valley Cat.

The variety with the most plants reported as producing at least one tomato as of July 2021 is Atkinson at 91%. Celebrity, Bella Rosa, Big Beef Red Snapper and Valley Cat are above 75% in this category.

On average, with nonproducing plants removed, the variety that has had the highest number of tomatoes produced has been Celebrity, with nine on average per plant, followed by a tie of seven between Big Beef and Valley Cat. These numbers should continue to increase throughout July.

As it did last year, Cherokee Purple is scraping the bottom in the average number of tomatoes produced (4) and percentage of plants reported producing at least one tomato (54%). In 2020 only 67% of the Cherokee Purple plants produced at least one tomato. Above 75% of this variety was reported as flowering in July, so hopefully it will pass it’s 2020 record by early August, when participants will be surveyed again.

If you check out these tomato varieties, you will notice that none of these are cherry or grape varieties. Cherry and grape tomatoes handle the heat very well and remain productive longer during the summer. If you’d like to be assured tomatoes throughout the summer and do not mind the smaller size, look for Sweet 100, Ruby Crush or Juliet to include in your spring garden next year, or your fall garden this year.

Just as a reminder, the Gillespie County AgriLife Extension Office has a tree program focusing on oak wilt on July 29, and the Fall Back into Gardening fall gardening program on Aug. 6. Additionally, I am pleased to announce that we will have a weekly Wednesday kids gardening program starting Aug. 25.

Please call our office at 830-997-3452 for more information about these programs.

Beth McMahon is the Gillespie County Horticulture Agent. Contact her at elizabeth.mcmahon@ag.tamu.edu.