Using Your Compost

Barbara Mrgich
Adams County Master Gardener

(6/29) Making and using compost in your garden has huge economical and ecological benefits. Maybe you have been learning about it and are convinced that your plants would grow better if you started producing what gardeners refer to as "Black Gold". It's very easy to understand how you would incorporate compost into a vegetable garden, however, you are mainly an ornamental gardener, and you mulch your garden with a decorative mulch, so how do you use the compost you have produced? This was my question when I started years ago, so I will share some of my discoveries with you.

Compost is not time sensitive

First of all, compost does not have to be completely "finished" (thoroughly and completely decomposed) before you spread it on the garden, and, on the other hand, the longer you keep it the more "finished" it gets. Therefore, there are no time constraints on its use. Keep it as long as you want, or use it whenever you need it.

Use compost as a top dressing

If you are getting ready to mulch an area of your garden, spread the compost just before you mulch. If some mulch is already in place, pull the mulch back from the plants, add the compost as a top dressing around your plants, then rake the mulch back over.

It is not necessary to dig the compost into the garden soil. The more you work the soil, the more earthworms and other beneficial organisms you chop up, and the more weed seeds you expose to the light which enables them to germinate.

Earthworms love compost and will increase rapidly with its use. They work constantly to aerate the soil. They will take whatever is on the top of the soil down to lower levels thereby working the compost down naturally. An additional benefit is that earthworm droppings are a great fertilizer.

Use compost in containers

I have a large trash can into which I drilled many holes. I fill it with partially digested compost from my open bins in the early summer, close the lid, and set it aside except to check it occasionally to see that it is still damp. By the next spring, it is totally digested and ready to use for filling my pots. I like to fill many containers around my garden, and buying potting soil to fill them all can become very expensive. I use my "trash can" compost and mix in a little perlite to improve drainage. The compost tends to retain more moisture, so the plants aren't as water needy as they would be in other planting mediums. Annuals or perennials, my plants get big and beautiful growing in my compost.

I buy large pots, and sometimes keep the same plants in them for years. I fertilize them, but I use an organic fertilizer as opposed to a chemical fertilizer to maintain life in the soil.

Use compost when planting

Anytime I am going to transplant or introduce a new plant, I first spread compost around the area. As I dig the hole, it mixes in. I usually mulch around the new plant with more compost.

Use compost for winter protection

I use compost in the fall to add a layer of protection to the roots of vulnerable plants which may be marginally hardy. I also use it around anything that was newly planted this year. A thick layer of compost covering the root system will keep the soil at a more even temperature protecting it from bitter cold, and from the alternate freeze and thaw which causes plants to heave (come up out of the soil). Remember not to pile the compost against the stem or crown of the plant, just as you would not pile it against the truck of a tree. We are zone 6B. Anything rated zone 5 or below will definitely be fine, but some zone 6 plants need protection if we have an unseasonably cold winter. For instance, I love Verbena 'Homestead Purple', and it is rated for zone 6, but it rarely ever came back for me until I started dumping some compost over the root area in the late fall. Now it usually comes back just fine. I even have some this summer that made it through January's polar vortex.

Eliminate the work of turning over the soil

Finally, when I want to start a new garden section, I pile as much compost as I can get, right on the grass. I plan ahead, and do this in the fall. The compost needs to be eight or more inches deep to smother the grass. By spring the decayed grass has become part of the soil. I simply dig my holes and plant nursery stock, or plant seeds right in the compost. Mushroom soil, which is actually compost, will work well. Mixing in a combination of shredded leaves and grass clippings makes it even better. This method has worked for me for many years and eliminates the backbreaking job of turning over the soil.

For information on how to make compost, please see my previous article titled, Composting Made Simple. Go to Master Gardeners, and look for mine and other master gardener articles.

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