Tomato fruit set temperature

The 2012 tomato season was poor for most people. I even heard about an elderly couple quitting gardening because of very low yield last year, saying, “It is just not worth all the work!” I think last year’s trouble was high temperatures.

Tomatoes, America’s favorite garden veggie, were hit especially hard. They require certain temperature ranges to set fruit. Night time, when the fruit is set, must be between 62 – 70 degrees F. Normally night temps fall into this range frequently and tomato blooms set fruit. But last summer, in June, night temperatures rose above 70 F and stayed there until August 10th. Below you can see that 2009 had days throughout the summer.

Green bars are days when night temps between 60-70 F.

In 2009 the last spring freeze was about April 7. But in 2012 the last freeze was March 7. Last year I luckily planted tomatoes early and the plants set fruit in April. But if you planted late, you might only get a few fruit clusters to set before the summer heat began.

 
I have to admit to “irrational exuberance” each spring. Spring fever is very strong. Today will be 80 F. I want to plant early.

But based on the charts and a generally warming climate, a little risk may reward with a better crop of tomatoes. Or am I simply feverish?

Either way, I have started enough tomato plants to risk a few. In my own little garden I have covered early plants with success. Covering them with plastic has protected them from light frost. Elm Tree Garden is bigger and would be more work to protect the plants.

I think I will start 50 feet of tomatoes next week and hope for the best. I have planned this with some Celebrity and Big Beef seedlings which are being hardened off for that last several days. They are ready. I also planned on enough seedlings to replace these plants if frozen.

Here the “Average” last frost date is April 1. But climate warming is happening and may have pushed the future last frost dates into March. I believe it has. Plant some of your tomatoes early in you are in Oklahoma and spread your risk.