Q. I went looking for compost at several reputable garden centers near me, but they all said they only sell wood mulches. One added that the house-staining artillery fungus you’ve warned about could exist in compost as well as wood mulch; can you dispute that claim? I did find one service that delivers shredded leaf mulch, but I was unsure if that would work the same as compost.  
            ---Jill in Ambler, PA

A. “Reputable” my red pepper! The garden centers you visited are simply trying to sell you what they have, and that’s wood mulch because it costs them a lot less to acquire than compost. A TRULY reputable garden center would not bad mouth compost; they would have it for sale.

And the explanation for their claim that compost causes shotgun fungus damage is simple, Jill: THEY’RE LYING, LYING, LYING!  Here are links to some University Bulletins and articles* detailing the dangers of wood mulch; and a link to the multi-University study** that recommends compost as a trouble-free alternative.

* http://ohioline.osu.edu/hyg-fact/3000/3304.html and
http://aginfo.psu.edu/news/july97/fungus.html
http://aginfo.psu.edu/PSA/ws2000/green5.html

** http://www.extension.iastate.edu/Publications/SUL12.pdf

Now, if the {quote}“shredded leaf mulch” you’re been offered looks like rich black soil, it IS compost—the very best kind, many experts feel. If it still looks like shredded leaves, it is not compost, but it will make an excellent mulch (it’s what I use). Shredded leaves don’t have the power to prevent plant diseases that they acquire when fully composted, but those leaves will prevent weeds, keep moisture in the soil, cause no problems whatsoever and feed your plants via the incredibly beneficial castings the worms that love living under it will provide. Composted or just shredded, its great stuff.

Q. I am interested in using “compost mulch”. What exactly is it and where can I get it?
            ---Holly in Princeton, N.J

Mike recommends we purchase compost for use as mulch in our beds, but we could not find any to buy. Or maybe my husband has been hosing me—he admitted he still wants to use wood mulch even after hearing about the problems it can cause. Is compost available in nurseries and garden stores?  He says he doesn’t see any.
            ---Lona in Southampton, Pa

“Compost” is the rich black soil-like substance created when organic materials like shredded leaves and yard waste are fully decomposed. Mulching with compost prevents weeds, feeds your garden, fights disease and doesn’t starve plants or stain your house with fungal spores like wood mulches.
 
And your best local source is also likely a free source. Most municipalities and townships compost the Fall leaves and other yard wastes they collect and offer the finished product back to their residents. Dr. Harry Hoitink, Professor Emeritus Ohio State University and internationally recognized expert on mulches, names this ‘yard waste compost’ his favorite type—as does Dr. Dan Herms, the Ohio State University Professor who oversaw the multi-University study that found compost to be superior to wood mulches.

Typically, you do have to pick this wonderful stuff up yourself—which is fine if you have a big old truck and like to haul stuff in bulk. But most of us are probably hoping to have something delivered. So call your local municipality or township office and see what the deal is your area. Maybe you can pay them to have a load delivered. If not, perhaps the guys who work the site can do it for you on the side. At the very least they should be able to recommend a local hauler who can bring you a load. If your municipality or township doesn’t have a composting site, call your local county Extension office to find out who does nearby; there are over 3,000 such sites nationwide.

And many garden centers and nurseries do have big piles of compost or composted mushroom soil for sale in bulk (the reputable ones, that is!). Of course, you’ll have to buy this compost, but they’ll almost certainly have a delivery system in place.

Q. Last year I very successfully used free compost from Lower Merion township to mulch my flower garden. I would like to also use it on my vegetable garden, but I’m concerned about chemicals from the yard waste used to make the compost.
            ---Sharon in Wynnewood, PA

There is a large municipal leaf pile near where I live, but the municipality sprays it's trees. Are pesticide residues destroyed in the composting process? How can I tell if compost is free of pesticides or municipal waste, like sludge?
            ---Judith; Newark, Del.

Only VERY large municipalities—i.e., big cities—compost sewage sludge (aka “biosolids”); such compost must be clearly identified and constantly tested for contaminants. But I still don’t recommend it because of the high levels of pharmaceutical resides it’s been found to contain.

I DO recommend municipal compost. To make sure that yours is high quality stuff, give it a look—it should be dark in color and crumbly in texture, with few to no original ingredients visible. Then give it a sniff—it should smell nice and earthy.

And yes, the composting process does degrade and eliminate any chemicals the original material may have contained—although the leaves that make up the bulk of this material are rarely subjected to pesticides. I’m not sure why a township would spray its trees, but the only chemical known to have resisted breaking down in composting was a lawn herbicide that’s since been banned.

Bottom Line: Bulk compost is vastly superior to wood mulch. It is THE basis for a happy, healthy landscape, and the vast majority of municipal composts, aged mushroom soils and the like are fine stuff. Don’t worry about it being 100% perfect; nothing in life is.

…other than ME, of course!

You Bet Your Garden   Question of the Week  ©2006 Mike McGrath

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