Fall frost precautions, peony and raspberry care

By John Fulton

[October 13, 2009]  For the most part, we dodged the proverbial bullet last week for a killing frost. The fog kept many plants from freezing, but with impending frost, it is important to take care of a few items. For protection, you could always try covers over the plants you want to protect. You will need to use something with a little bit of insulation value, such as cardboard, blankets or row covers. The row covers themselves don't have much of an R-value, but the air space between the cover and plant does. Just laying a cheap tarp on your plants will usually result in at least some damage to the top parts of the plant. And if there are windy conditions, it may be about impossible to keep much of anything covered.

If you are ready to have the season conclude, harvest what you can. The main things to harvest prior to a frost or freeze are squash, pumpkins, cucumbers, melons and tomatoes. Virtually everything in the garden will be affected except for frost-tolerant crops such as lettuce, spinach, radishes and the like. The main problem with any of the vining crops is the possibility of the vines rotting back to the vegetable. This in turn means they won't keep well. Unfortunately, vining crops harvested early won't continue to ripen. Green pumpkins tend to stay green.

For tomatoes, you may pick green tomatoes and they will ripen after a period of time. The best way is to pick firm, good-quality fruit and wash well with soapy water. After they are dry, wrap in newspaper or tissue paper and place on a rack or in a cardboard box in a single layer. Check periodically for tomatoes going out of condition or becoming ripe. To speed things along, you can try putting a tomato in a paper lunch bag with a banana peel. Bananas are high in ethylene, which is the same thing used in a gas form to ripen tomatoes in transport during the winter. Of course, the flavor just isn't the same as a vine-ripened tomato, but tomatoes in the fall or winter are good regardless.

As for flowers, the same principles of protection apply to annuals. Of course, if you have hanging baskets or potted plants, you can simply put them in a garage or shed until the danger of frost has passed. The key point is that having one or two nights of frost followed by a week or two of good weather probably justifies some protective measures. A frost every night for two weeks or a long period of freezing temperatures probably means major efforts will produce very little gain.

Fall care of peonies

Peonies are one of those "plant it and forget it" flowers. Many haven't been bothered for over 50 years and still going strong. As with most plants, crowding can occur, and the time to dig and divide is late September through October.

Peonies do best in soils with a slightly acid to neutral pH. The best time to add lime, if needed, is when you dig the plants. When dividing, make sure you leave buds on each piece you plan to plant. These buds should be no deeper than an inch when replanted to allow for proper flowering. Mulching will help yearlong on any plant, and peonies are no exception.

Pruning raspberries

To start with, remove all the dead, short and weak canes on raspberries. The large remaining canes are thinned to 4 to 8 inches apart. The canes are cut back to 5-6 feet tall or, if no support is provided, 3-4 feet tall. The canes that produced last year should be removed anytime after harvest or removed in the late fall. Canes are productive only one year, and the new growth will produce the next year's harvest. The exception is the Heritage, or ever-bearing, raspberry, which produces two crops of berries. One is in the fall and the second is late spring or early summer. These berries should have the canes removed after the late spring or early summer crop.

[By JOHN FULTON, University of Illinois Extension, Logan County]