Friday, 28 October 2016

After the freeze – now what?

Photo of Sandra Mason Sandra Mason
Extension Educator, Horticulture
Each October Midwestern gardeners live with the looming knowledge of the inevitable freeze. Just like death and taxes we know we can't escape, but we would sure enjoy a delay. This year it arrived pretty much on schedule; however it still makes me sad to see the limp sodden skeletons of my once voluptuous plants.
All that is left now is the clean-up. You may find a few tomatoes or peppers that appear free of cold damage even though their mother plant hangs like cooked spinach. Go ahead and harvest. Green tomatoes will ripen indoors and do not need sunlight to ripen.
I often get the question about whether it is safe to eat vegetables after a freeze. It is really more of a quality issue than a safety issue. If the tomatoes and peppers appear just fine with no squishy areas, go right ahead and eat them fresh or use in cooking. However we do not recommend processing them such as for canning because of the concern that freeze damaged tissue may allow bacteria entry. Only vegetables in their prime should be processed.
Pumpkins and squash can also be harvested, but if they were not completely ripe they may not store or hang out on your porch as long.
Some vegetables shrug off the cold with hardly a shiver. Chard, carrot, kale, turnip, mustard greens, parsnip, radish, salsify, spinach and rutabagas do fine in cold weather and their flavor is better after a frost.

We saw a bounty of apples this year. Apples left on a tree during a frost are just fine for eating and cooking. If temperatures got in the mid to lower 20's than again it is a quality issue and not a safety issue. Apples that have gone through a severe freeze may not store as long, but are perfectly tasty.
Probably the concern over eating produce after a freeze goes back to one plant – rhubarb. We don't harvest rhubarb in the fall anyway but in the spring a late frost can cause concern. We eat the rhubarb stalks and should never eat the large leaves any time of year. The leaves are inedible because of oxalic acid and oxalate content which can cause poisoning.
In response to low temperatures, oxalic acid increases in rhubarb stalks as leaf tissues begin to freeze. Frozen plants will have water soaked limp leaves. Do not eat wilted or limp stalks from obviously frostbitten rhubarb plants.
A few things you can do in the garden after a fall freeze-
It is not too late to dig tender bulbs such as dahlia, caladium and canna even if the top part of the plants have been singed from cold. Store in sawdust or peat moss at 55 degrees F.
Plant garlic cloves and spring flowering bulbs such as tulips, daffodils, crocus and lesser known winter aconite and snowdrops.
Clean limp plant remnants from the garden. Start a compost pile with all the leaves and garden debris.
Strawberries should be mulched before temperatures go below 20 degrees F. Use a loose mulch of clean wheat straw to a depth of 3 to 4 inches. I have had good luck using pine needles for mulch in strawberry beds.

Apply to the Master Gardener program today. Training for Master Gardeners in Champaign, Ford, Iroquois and Vermilion counties starts the end of January 2014 in three locations; Champaign, Danville and Onarga, but applications are due December 6, 2013. Check out our web site for more information and to apply online
Questions? Our great horticulture team is here to help: in Champaign (217.333.7672) Ava Heap; in Danville (217-442-8615) Jenney Hanrahan and Leah Brennan; our new horticulture educator Diane Plewa; or me at

Check with your local UI Extension for their opportunities.