Mulching is important in the fall

Q. A master gardener told me that I should mulch in fall. Is this true?

Lynn from Austintown

A. Yes, fall mulching may be the best thing you do for your garden.

When it comes to mulching most people think of it as a springtime chore. When the weather warms, mulch is bought, put down and then it is put out of mind until next year. But it is just as important (and maybe even more important) to mulch in the fall as in the spring. And, unlike the spring, almost everyone has a ready supply of mulching material in the fall. More on this later.

Fall mulching provides the same benefits as spring mulching. It retards weed germination, protects against temperature fluctuations, and helps retain soil water. Retaining water in the soil is especially important for evergreen plants in the fall and winter to help prevent winter desiccation. When the soil dries out or freezes, evergreens can’t replace the water lost from their leaves. If this condition continues long enough, the tissues in their leaves and stems begin to die. Adding mulch in the fall over the root zone of these plants keeps the soil moist and delays its freezing, giving their roots longer access to water.

If you already have bark mulch down, check it to see if the mulch has crusted over. Crusted over mulch prevents water from penetrating into the soil. Any crust you find can be broken up with a rake or other tool. Don’t mulch in the fall too early. Plants use cooling air and soil temperatures as one of their signals to go into dormancy for the winter. Adding mulch too early can disrupt this process. So depending on the weather, wait until mid-November or later before adding mulch. Don’t mulch too thickly – 3 to 6 inches is good – around woody trees and shrubs. Too much mulch makes a winter home for mice. And while at home the mice can chew the bark of your plants.

And please, no volcano mulching. Mulch, heaped around the trunks of trees or shrubs, creates problems that can shorten the life of the plant. So keep mulch a few inches away from the trunks.

You can use the same material for mulching in the fall as in the spring. But this time of the year you probably have a free supply of great mulching material laying on the ground. Yes, I am talking about leaves. Leaf mulch is great for landscape plants. Using leaves as mulch maintains the natural nutrient cycling between decomposing leaves, the soil, and nutrient reuse by plants. Leaf mulch is lighter weight than bark mulch, making it easier to work with. It’s better to use shredded leaves for mulch than whole leaves. Whole leaves can pack down when they get wet, smothering the plants you are trying to protect. To shred the leaves, set your lawn mower at its maximum height setting and mow them. Mulching blades work great, but regular mower blades will also get the job done, although you may need to mow them twice. A bagger on the mower will make it easier to collect the shredded leaves. And mulching in the fall means less mulching next spring.

For more information see: http://go.osu.edu/fallmulching

This week’s question answered by David Sprague, an OSU Extension master gardener volunteer in Mahoning County. Meet him at the Plant and Pest Clinic. Call the clinic at 330-533-5538 to submit your questions. Regular clinic hours are 9 am to noon Mondays and Thursdays.