Ten Commandments of Mulch

Question. I really enjoy your show and wanted to know if you could suggest a brand of mulch that's naturally black in color. The mulch I've purchased in the past starts out black,but turns brown.  Thanks,

---Kimberly in Wilmington, Delaware.

Following your advice, I called a nursery about getting leaf compost to use instead of mulch. They couldn't understand why we wouldn't want to use mulch. They said compost would burn the trees because it was too acidic. They also said if it's used in the right amount and isn't moist, wood mulch works perfectly and has never caused a problem. Isthis true? I would like to use compost, but I'm discouraged by what the nursery is saying.

---Lisa In Merchant ville, NJ

Dear Mike: I'm seeing a lot of shredded, dyed rubber mulch made from used car tires in home stores. My brother in Hollywood, FL, has started using it, but I don't even like calling it 'mulch'. I only use compost on my garden beds, but my brother likes the quick fix and I'm worried that the rubber mulch will break down and release byproducts that could contaminate the shallow water tables in places like Florida.

---Steve in Morris ville, PA

I am looking for the best way to remove shotgun fungus spores from mysiding. I read the articles from Ohio State University, but didn't see any mention of removal strategies.  Thank you!
            ---Barbara in Northern Michigan

Answer. Ah yes, 'tis the season of Mulching Mistakes. Tell you what—I'll answer all those questions andmany more, and sum up everything you need to know about this topic in aseries of tips and treatises we will call:

The Ten Commandments of Mulch

1.    The word "mulch" does not mean wood chips orshredded bark. "Mulch" isanything that covers the soil to retain moisture and prevent weeds. Nurseries would LIKE you to think that wood = mulch because they're often paid to take wood chips and shredded bark from tree cutters trying to avoid high landfill costs. If they can then sell it to you as mulch, they get paid twice.

2.    There is no better mulch than compost . No, compost is not acidic and it doesn't harm plants (it's plant FOOD!). But nurseries have to actually buy compost, so some might tella little…eh, 'fib' to achieve that higher profit. Did I just say,"fib"? I'm sorry—that's not fair. I meant to say: "Liar, liar; pants on fire". I apologize for the error. Anyway, in a groundbreaking study from Iowa and Ohio State Universities two inches of compost prevented weeds just a swell as two inches of ground wood mulch. And the compost provided all the food it's plants needed for the season, while the wood mulch actually increased the plants' need for food (see #9, below). You gonna believe some guy what wants to sell you wood to make a bigger profit?Or the published results of University researchers?  

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3.    Compost is pretty. When I spoke with that study' slead researcher, Dr.Dan Herms, he observed that the compost mulch was as black and nicelooking as the dyed black wood mulch they were testing it against. It looked so nice, in fact, that he switched to it personally. Simply put,a mulch of compost provides all the benefits you can get from mulch with none of the negatives of wood or other troublesome mulches. Other mulches of high regard include shredded Fall leaves, pine needles and pine straw; and really cool esoteric local ones like cocoa bean shells and rice hulls.

4.    Wood mulch is not nice—especially dyed wood mulch.It's made by grinding up old pallets and other trash wood, and may contain arsenic,creosote and other nasty stuff. It is the lowest quality mulch you can buy. Oh, except for…

5.    Rubber mulch is WORSE! You know you have to pay to throw away your old tires. Do you really think it's a smart idea to buy them back after somebody grinds them up and calls them mulch? Rubber mulch leaches zinc and other pollutants; and it STINKS in the summertime. Why does everyone with a toxic waste disposal problem always have to think,"Hey—I'll bet we can convince people to use this stuff in their garden!"?

6.    Thou should not use wood mulch near thy home. As many hundreds of listeners have told us they learned the hard way, any kind of woodmulch—like wood chips, so-called triple-premium shredded bark and those increasingly popular root mulches—can breed a nuisance mold known as' shotgun' or 'artillery' fungus that will permanently stain homes and cars within 30 feet of the mulch with impossible to remove fungal spores that look like little tar balls. Sorry, but the reason

7.    Thou should not run ANY mulch right up to thy home. Everyone in America has subterranean termites in their landscape. Subterraneans prefer to travel under cover. Mulching right up to the side of your home with anything—even stone—provides the protection and moisture they require to find their way RIGHT to your framing. Always leave at least a six-inch area clear around your home.

8.    Never touch a plant with any mulch. Mulches are for preventing weeds and retaining soil moisture—they are not blankies; they do not keep plants warm or comfort them. Just the opposite, in fact: ANY mulch that's piled up against a plant stem or tree trunk provides cover and traps moisture, inviting pests, disease and rot to destroy that poor plant. There is no good reason for mulch to ever touch a plant; there are many good reasons for it not to. Always leave a few inches wide open around the trunk or stem.

9.    Wood mulches starve plants. As we have often warned, wood is high in carbon. Carbon seeks out nitrogen to help it break down into soil, just like in a compost pile. Mulch your plants with wood and the wood will steal their food in its quest to become really nice dirt a few years from then. When I hear that a plant isn't thriving, my first response is generally, "get rid of the wood mulch".

10.    You CAN use wood mulch! It's great for smothering unwanted plants and keeping weeds down in walkways far away from homes and cars.

For even more info, check out last year's diatribe on this topic:
Is your Mulch Magnificent or Miserable?

You Bet YourGarden ©2006 Mike McGrath