Average frost-free date May 4

Q. What are the frost-free dates in our area?

Ava from Youngstown

A. The frost-free date for our area varies, depending on many factors. Mostly, it’s the weather. In general, we like to think of Mother’s Day as the “nearly, almost, generally, usual” date. Although our spring is behind schedule, nature may catch up and that date might hold true for 2014.

According to our colleagues at Utah State University, the average frost-free date based on 76 years of data for Youngstown is May 4. The latest is June 11. You can look at their data on this site: http://go.osu.edu/frostfree.

If you’re worried about planting annual plants and vegetables in the garden, the frost-free date is something to think about, but nothing to fear.

The date is not applicable to many early season vegetables. There’s a great chart on this fact sheet — http://go.osu.edu/vegsoiltemps — which tells the soil temperatures at which many seeds will germinate. Early-season vegetables such as onions, parsnips, cabbage and related plants will germinate when soil temperatures are around 40 degrees. But they germinate best when soil temperatures are above 70. Thus, most early-season plants should be started inside and transplanted. If you are planting seeds outside, you need to be sure the soil is well-drained and soil temperatures are well above the minimum.

Planting of transplants in the spring can be done in pots without fear of affecting the growth of the plant. But some plants (such as annual vinca, Catharanthus roseus) will be slowed in their growth if planted in the ground. Many times this is due to root rot infecting the plant because of cold, wet soils. Thus, if planting transplants – pay attention to drainage and soil temperatures.

Finally, you’ll want to plan for frost protection no matter what date you plant tender transplants. Never use plastic, unless you build a small structure that keeps ground heat in and keeps the plastic from touching plants. Instead, have adequate numbers of sheets or row covers ready. If you’re an avid gardener – you know it can sneak up on you in the “average” year.

Eric Barrett is OSU Ext. educator for agriculture and natural resources in Mahoning County. Call the office hotline at 330-533-5538 from 9 a.m. to noon Mondays and Thursdays to submit your questions.

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