For Release April 30, 2002

AGRI-VIEWS
by Chuck Otte, Geary County Extension Agent

It’s the end of April. Spring has been upon us for almost seven weeks. During the official spring season we’ve seen a little spring, a little winter, and some might even say a touch of summer. Brave gardeners have probably already pushed the envelope and put out some of the more frost tender plants. Which raises the question, is it time yet?

Spring is a cruel time of year. It teases, it hints, and yet it can’t seem to always make up it’s mind. I thought we might have an early spring. January and February were both well above normal. Then March hit and we wound up quite a few degrees below normal. One thing that I have decided about spring, after living all my life in the Great Plains, is that it can change it’s mind in a hurry!

Local gardeners are always calling me up to find out when the last frost of spring occurs. Wellllll, do you mean the average last date of frost, or the frost free date? There is a difference. Over the last 50 years, the average date of our official last 32 degree reading in the spring has been the 16th of April. Two thirds of the years the last freeze has been within 12 days of April 16th. BUT, the total range of when this can occur is huge. The earliest that the last freeze of spring has occurred is March 18th. That was in the very drought year of 1988. The latest that we have seen 32 degrees is May 14th. That was back in 1953. I guess you could say that, at least since 1951, May 15th has been our frost free date. For all practical purposes, we have probably seen our last 32 degree reading.

But figures are so deceiving. We can have plant damaging frosts with thermometer readings above 32. Your garden can easily sit in a low spot where cold air collects. It may be 35 degrees at your house but 28 degrees just above the soil level in your garden. Even if we don’t have anymore freezing weather, it doesn’t mean that it’s a good idea to be putting out all of your plants yet!

Many very popular garden crops, such as tomatoes and peppers/chiles, are very cold sensitive. They don’t like to get their little feet cold. These are tropical plants that like warm weather and warm soil. You can take a perfectly good tomato plant from the greenhouse, set it out into cold soil, even if you put your wall of water around it, and literally shock it into reproductive dormancy. If it gets too cold it will literally turn a bluish purple color.

If you are going to set out a few early plants, use some of the shorter season varieties. Some of these have more cold tolerance. Then harden them off for a few days first by setting them outside still in their pots. Then you can put them into the ground. There are also some older heirloom varieties that are advertised as being more cold tolerant. You may want to consider some of these for future attempts.

Okay, I still haven’t really answered your question. Is it time yet? Not for everything. My rule of thumb is that you shouldn’t put out all your tomatoes and chiles until Mother’s Day or later. By then, the soil is usually going to stay warm enough that we should have less than a 2% chance of frost or cold weather problems. Oh, by the way, sweet potatoes don’t figure in to this discussion. You may want to hold off on them until closer to Memorial Day! But that’s another story!

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