A friend asked me last week where to get the cheapest mulch. It’s a pretty easy question but it really should be prefaced with a bit of background. We’re all familiar with the various colors and materials seen around plantings in front of businesses and in parking lots. Some of the common kinds of mulch are, shredded hardwood, pine bark, broken brick, , pinestraw, even crushed glass is sometimes used. Often hardwood mulch has dies added to turn it red or dark brown.  It usually fades within a year to a light grey brown color. In my area pinestraw is prefered by many. By prefered I mean there is a certain kind of person here known as a straw-nazi. Straw-nazis can be very peculiar about the various nuances of straw mulch application.

Mulch is necessary not because it prevents weed growth, though enough of it certainly can slow them. It is necessary because without it myccorhisal fungi and beneficial bacteria cannot proliferate within the soil. In fact there is a complex ecosystem beneath the mulch layer without which we couldn’t have healthy plants.

Myccorhisal fungi form a simbiotic relationship with the roots of plants without which plants are unable to glean nutrients from the soil. Other fungi and bacteria break down organic mater and humus in the soil into constituents which can be absorbed by the plants. Humus (not humos although also great) is organic matter that has been broken down to the point at which it resists further decomposition . Humus in the top layers of the soil contributes to tilth or workability of the soil. Tilth makes the soil more hospitable to macroorganisms such as earthworms which make oxigen as well as nutrients available to plants. Humus also provides a long term reserve of nitrogen and phosphorus.

In order to create humus, organic matter must continually be added to the soil. This organic matter must be made available to micro and macroorganisms that can break it down. In order for this to happen a warm moist habitat protected from the sun and predators must be established. Thats where mulch comes in. The right mulch can create this habitat as well as return organic matter to the ecosystem. Thereby it  continually renews the humus in the soil in the same way that the layer of leaves on the forest floor does. In fact when you mulch you are creating a simulated forest floor for your plants. So by mulching with organic matter such as composted leaves we not only create a uniform surface beneath out plant but we introduce organic matter to the soil and create a habitat for the little critter plants need to survive.

However this process can be complicated by the contents of the mulch you use. Hight tannin content in organic matter such as shredded wood mulch or pine bark can cause protiens in that material to sequester nitrogen and remove one of the most important nutrients from the underground ecosistem plants need to survive. Mulches with high acid content such as pine straw can  lower the PH of the soil. This may be desireable in the case where mulch is applied around acid loving plants such as azaleas.

So as a general rule I try to stay away from shredded wood mulch. In fact in my oppinion composted leaf mulch is the only game in town. Since we now understand what mulch does and which mulch to avoid where can we get the stuff cheap.

Most municipalities now have several kinds of compost available, shredded yard waste, biosolids and sometimes leaf mulch and even crushed glass. Check with your cities or counties landfill. Also check with the environmental department. Compost businesses are popping up all over. If you don’t have a truck or trailer you can sometimes have them deliver. If they can’t then they’ll know someone who can. Another source could be neighbors. One idea is to offer to rake a neighbors leaves and compost them yourself. Personally I’d use fresh uncomposted leaves from my own yard rather than wood mulch. That would certainly be the cheapest rout.

If you want to spruce up you mulch you can combine mulches. One mixture I like is three parts leaf mulch and one part pine bark. This mixture gives you the look of pine bark and the leaf mulch helps the soil and holds the bark in place during rain so it doesnt end up all over the place.

Here are two links which can help you find your next mulch;

http://www.carolinacompost.com/

http://www.p2pays.org/compost/

Advertisement