I find Pennsylvania Ag Clips in the garden club inbox every morning. In the March 31 addition there were some thoughts by Tim Fritz from King’s AgriSeeds on how the odd weather patterns are going to affect the planting season. He was suggesting that farmers reconsider when they plant their crops this year. We aren’t farmers but some of what he says might be applicable to our planting practices
Due to various weather patterns, we have had a very cold, wet winter. Forecasts suggest that temperatures through March, April and May will continue to be below average. If this is true we will have a longer window for planting cool weather plants. While we usually need to get our cabbage, broccoli and cauliflower in early in May we might want to wait until a week or two later. While it is important for a good root system to be established on these plants before the warmer weather sets in, very low temperatures can have an adverse effect. Cauliflower, in particular, will not head up if exposed to very cold temperatures. While many of cool weather veggies and flowering annuals can be sown in soil with a minimum temperature of 40° F, they probably aren’t going to germinate until the soil temperature reaches at least 50° F or warmer. The longer the seed is in the soil without germinating the more likely it is going to rot or be eaten. Peas in particular like a cool soil but chipmunks and other beasties seem to love peas.
Warm weather crops are even more vulnerable in cold soil. Corn and beans require a minimum soil temperature of 50° F for germination. Squash and cucumbers require about 10° higher and flower seeds are mostly at these upper ranges, as well. Remember that these are minimum temperatures and they will result in minimum germination. All warm weather plants prefer soil temperatures of around 70° for maximum germination.
Setting out peppers and eggplants in cooler conditions will result in disaster. They like lots of heat. Tomatoes are less vulnerable but again they are warm weather crops and don’t like cold feet. A late frost will send you scurrying for rugs, blankets and sacks to cover unhappy plants that might take some time to recover from adverse conditions.
Check your soil temperature this year before you put out your plants or sow your seed. Measure it at a depth of about 4-6 inches and take a morning and evening temperature so you can get an idea of how much of a range that you are dealing with. If the weather persists in being as erratic as it has been counting back from the normal last frost date isn’t going to be a very good guide for planting this year.