Frost damage in central Phoenix.

While on our morning walks this week we’re seeing a bit of frost damage from the recent cold nights. Your first inclination might be to prune away the dead, ugly parts of the plants but please wait. Here’s why.

If any of your plants suffer frost damage there are two really important things to remember when managing the plant:

1) The last average frost date ranges from Feb. 7 in the central part of Maricopa County to April 3 in the far east Valley. (That’s hard to believe but remember we’re dealing in averages.)

Wait for new growth to appear before pruning.

2) Do not prune any frost damage from plants until new growth emerges in the spring. Frost damage isn’t pretty, but it will help insulate the plant if there is another freeze.

Going forward, you’ll need to keep plants well watered. Frost injury occurs when ice crystals form on the leaf surface drawing moisture from the leaf tissue. The damage from this dehydration will be less severe if the plant is not already drought-stressed. So, you’ll want to keep everything evenly moist, not letting things dry out too much.

When it looks like temperatures will dip below freezing, cover your plants with sheets, blankets or towels. It’s best to hang the frost covering over stakes placed around a plant, not lay it directly on the leaves.  If possible, let the covering hang to the ground to trap heat, but don’t tie it to the trunk of the plant because you want to get as much heat off the ground and close to the plant as possible.

The UofA has a great primer on frost, frost protection methods and after-frost care practices that is worth printing out as a guide – click here to get it.


What To Seed In January

According to our well-worn copy of  “Desert Gardening for Beginners” January is a good time to seed beets, carrots, green onions, mustard greens and radishes. You can still also seed lettuces, chard and spinach, but they will bolt if we get an early spell of heat. The beets, carrots, etc will continue to produce well into a warm spring.