It seems like spring is finally here. The garden shops and nurseries are overflowing with every flower or vegetable you’ve ever wanted to grow. If you’ve spent any time in Kansas, you know that the volatility of our weather often defies prediction. Freeze and frost advisories are only issued during the growing season which runs from mid-April through late September. An unexpected cold spell can wreak havoc in your garden and blow your budget. Frost advisories are issued when the minimum temperatures are forecast to be between 33-36 degrees. Frost usually occurs overnight or early in the morning. A freeze warning is issued when temperatures are expected to be between 28-32 degrees. Finally, a hard freeze warning is issued when temps are forecast to be below 28 degrees. This spring has been particularly cold. If you’ve been trying to get your garden started, be patient. Hardy plants won’t suffer from frost, but tender ones might not make it. An unexpected freeze could kill all of your annuals and tender perennials.
It’s important to know which plants can handle cold weather and which ones can’t. Different food crops handle cold differently. Members of the brassica family include collards, kale, cabbage, Brussel sprouts, broccoli and cauliflower. They’re hardy enough to handle cold weather. Spinach actually thrives in cooler temps. There are some crops that have absolutely no tolerance for frost. These include tomatoes, cucumbers, peppers, eggplant, watermelon, corn, squash and basil. There’s no benefit to planting these crops early. It’s not worth the risk. Wait until after Mother’s Day when there’s no more chance of frost. Like vegetables, some flowers tolerate cooler temperatures better than others. Pansies, petunias and geraniums are among many flowers that prefer cooler temperatures.
Even though roses have started to leaf out, it’s still too early to start pruning. Resist the urge. Pruning stimulates growth and any new growth would likely be killed by a sudden frost. Recovery from cold weather injuries could set your roses back by several weeks.
The best way to protect your plants from an unexpected cold spell is to pay close attention to the weather forecast. Don’t let chilly weather catch you by surprise. Frost happens when water vapor settles on surfaces and the temperature falls to 32 degrees.
During a frost or freeze advisory, water your plants deeply. Well-hydrated plants tolerate cold better than dry ones. Also, moist soil retains heat better. Cover your plants the evening before frost has a chance to set. Protect them with mulch, inverted pots or five-gallon buckets. Use anything to keep the cold air off. Bring your potted plants indoors. If you’ve planted your tomatoes too soon, drape blankets or sheets over their cages. Frost is usually a short-term event, so be sure to uncover your plants the next morning.
Don’t attempt to treat any cold weather injuries until all threats of frost have passed. Wait until new growth appears. Remove any dead foliage and trim away any obvious wounds until you reach healthy plant tissue. Sometimes when your plants have been damaged by the cold, the only thing you can do is replace them.
Rachel and Ivan Minnis are avid gardeners. They live in Leavenworth. For more information, visit The Minnis Rose Garden on Facebook. Contact them at firstname.lastname@example.org