My garden is thoroughly enjoying the early arrival of spring except for one thing. Every time it looks at the calendar it has a nervous shutter. The temperature is right, the soil is perfect and the weather report is perfect so what is the problem?
As I am writing, a few seconds of research tells me that the record low for today was 20 degrees set in 1990. Several years ago the band of states eight or ten hours south of here experienced a quick warm up followed by sudden plunges to record temperatures.
A plunge to 20 degrees here now would be equally catastrophic. Before we panic, let's evaluate mitigating factors. If the ten-day forecast holds, the record low then is 27 degrees set in 1999. That would be a problem, but not catastrophic.
Also note that a drop from a nightly low of 60 degrees to 30 degrees in one day is a lot worse than if it went from 60 to 55, 55 to 50, 50 to 45, 45 to 40, 40 to 35 and finally 35 to 30 over six days.
Several days ago I was cautioning a neighbor about planting when he retorted that I was colder than he was. I had to agree. There have been a few times and special weather conditions in memory when I saw a 10-degree difference between my place and his. He lives less than half a mile away.
In my car I have one of those outside temperature monitors. Its fun to watch the wide temperature ranges you can experience in short distances. The bottom line is you will be much more successful if you make yourself aware of the microclimate in your garden.
Am I itching to make some risky plantings of annuals? Sure. How can you help it?
If you buy annuals now, ask the person on the other side of the counter about the risk. If they are risky and you are still buying, hold them a bit. To hold them keep them outside out of the afternoon sun. Keep them moist but NOT WET. If the temperature plunges, take them inside and return them outside as soon as it warms.
Also try to gauge how your annuals were grown. What was the nighttime temperature the day before you bought them? If they were grown at the industry norm of mid 60ies going outside can be a jolt. Grown slower at cooler temperatures and run with reduced heat before selling is a major plus.
Some annuals will handle light frost. They include pansies, calendula, vinca vine, dracaena(spikes), and dianthus.
Annuals that will tolerate temperatures near but above freezing include osteopermum, verbena, snapdragons, salvia, alyssum, and petunias.
Some annuals want it to stay above 40 degrees. They include coleus, marigolds, zinnias and geraniums.
Then there are those who will not tolerate temperatures below 50 degrees. They are the tropicals: impatiens, vinca(flowering), begonias, celosia, mandevilla and the like.
Know your site. Know your plants. Know how to hold plants in their greenhouse containers. Know the risks of planting annuals in April. After that, you have my permission to get dirty.