There comes a time in every avid gardener’s life where you take a good, long look at yourself in the mirror and admit that you are putting too much time and energy into one area of your garden. The cries and moans from the neglected areas in your garden have finally made themselves heard and it is time for change.

Maybe you’ve gone a bit overboard ordering vegetable seeds the past few years and need to scale back. Or maybe the garden art in your landscape is getting a little out of hand and starting to takeover plant communities. Or maybe, just maybe, you are scared of venturing away from the tomatoes in case a stray stink bug chooses one of your luscious fruits to dine on.

I understand. Really I do.

I, too, am suffering from misdirected energy, a recently discovered gardening disease called “OCD”, Obsessive Composting Disorder. I run out of things to compost and start rummaging through neighborhood green waste bins. I sometimes have dreams that truckloads of organic materials have been dropped at my house by compost angels. I follow landscapers around and plead for burlap wraps of lawn clippings...It’s a problem. I am working on it.

So, the upside of my issue is that I have a bunch of finished compost on hand. So much that I had to find creative ways to use the stuff. Luckily, there is new research that has expanded the use of compost in the landscape and garden. Now, researchers are finding interesting attributes of compost that can be applied in a wide variety of situations. Lets look at the traditional and the new ways of using compost.

Using Compost as Mulch

Compost can be used as a mulch layer and provides many benefits for gardeners. If using finished compost as a mulch, spread a 2-4 inch layer on the soil surface, being sure to keep the compost a few inches away from plant stems and tree trunks. This “top dressing” will help minimize fluctuations in soil temperature and moisture, while also adding organic matter to the soil over time.

The one drawback of using compost as mulch is that it does not provide effective weed control. If using unfinished, coarse compost as a mulch, it may provide a decent barrier to weed seeds; however, it also may steal nitrogen from the soil while it decomposes.

It may be best to use finished, well screened compost as a layer of mulch, but then top off with a standard mulch material to keep weed seeds from sprouting and getting established.

Using Compost as a Soil Amendment

Compost is by far the best overall soil amendment to add to existing garden or landscape soils. It can be incorporated into the soil before planting all types of plants, shrubs, and trees. It improves the structure and drainage ability of poor, heavy soils. It also “feeds the soil” by providing organic matter for microorganisms to feed on, thereby releasing nutrients for plants to use.

To use compost to enrich soil, thoroughly mix the screened compost material with the top 6-10” of existing soil. It is not as efficient to simply place a handful of compost into a planting hole. Mix about 1-4 inches of compost into annual planting beds each year to maintain fertility and improve soil quality. In general, compost can provide up to 15% of nutrient needs for annual plantings. In established perennial beds, on lawns and around trees and shrubs, “top dressing” is the preferred method to avoid damaging precious roots.

Using Compost in Potting Mixes

Compost makes a great addition to potting soils and seed starting mixes; it helps to hold moisture and release it slowly. It is essential to use mature compost that is finely screened to maximize its benefits. When using compost to create potting mixes or seed starting material, it should make up no more than 1/3 of the total mixed volume. Other materials commonly used with compost are: coarse sand, peat moss, perlite, and vermiculite.

New Uses for Compost

Although compost has been used for centuries in home gardening and commercial farming around the world, it is quickly becoming a more versatile and beneficial material than previously acknowledged.

Compost is being utilized on many different levels by many different people in the areas of:

• Erosion control
• Turf grass management and remediation
• Wetlands restoration
• Biofiltration for odor control
• Storm water runoff filtration
• Plant disease suppression in crop production and nursery industry

Research findings are uncovering amazing benefits of using compost in all these situations.

References

Master Composter Training Manual. 2002. UCCE Placer – Nevada Counties.
Cornell Composting. http://www.css.cornell.edu/ compost/ Composting_Homepage.html
CIWMB Compost and Mulch. http://www.ciwmb.ca.gov/organics/ CompostMulch/