Mulch: The Cheapest Thing You Can Do
I'll die on this hill, and if you've been in my yard you've heard me say it already. Mulch is the cheapest thing you can do for your plants and it's the thing almost everybody skips. They spend all their money on the plants and none on what goes around them. Exactly backwards.
Here's why it matters so much. Bare dirt in a Utah summer bakes. The sun hits it, the moisture down in the root zone walks right out into the air, and your plant is sitting in dry soil by two in the afternoon no matter how well you watered that morning. Cover that same dirt with three inches of mulch and you've put a lid on it. Water stays down where the roots can use it. The soil underneath stays cooler too, which the roots like a lot better than getting cooked at the surface.
And weeds. A good layer of mulch blocks the light those weed seeds need to sprout in the first place. Not all of them, nothing's perfect, but you go from pulling weeds every weekend to pulling a handful every month. That alone is worth the truck trip.
What kind, how much
Two real choices for a xeriscape bed: wood mulch or gravel. Both work. Wood breaks down over a few years and feeds the soil a little as it goes, which I like for beds with a lot of plant. Gravel doesn't break down, so it's more of a one-time job, and I use it more where I want a drier look or right up against the house.
Either way, about three inches. Not one inch, that's not enough to stop the sun or the weeds. Not six inches either, that's more than the roots want and it can hold too much moisture right against the stem, which invites rot. Three inches, spread even.
One thing I have to say plainly because I see it done wrong constantly: keep the mulch off the actual stem or trunk of the plant. Pull it back a couple inches so there's a little gap. Mulch piled right against the stem holds moisture against it and that's an invitation for rot and for bugs that hide in damp bark. You want a doughnut, not a volcano.
The Christopher story
My grandson Christopher was about six when he came out to help me mulch a new bed one Saturday. Great kid, all enthusiasm, and I made the mistake of handing him a full bag and walking off to grab the rake. Came back and he'd dumped the entire bag in one pile, about three feet high, right on top of one poor little penstemon. He looked so proud. Told me "so the plant would be extra happy."
Didn't have the heart to spread it out right then. Left that pile sitting a full week before I could bring myself to fix it, partly because I was busy and partly because I liked looking at it and thinking about him. The plant was fine, by the way, once I finally spread it properly. But that's the picture I want in your head when you're doing this yourself: not too thick, not piled on one plant, spread even across the whole bed like a blanket, not a hill.
Steps for this weekend
- Figure your square footage. Length times width of the bed, roughly.
- For three inches of coverage you're looking at about one cubic yard of mulch per 100 square feet. The bag says how many cubic feet it covers, do the math before you load the truck.
- Weed the bed first. Pull what's there now, because whatever's under the mulch when you lay it down is going to try to grow up through it.
- Spread it with a rake, three inches deep, pulled back from every stem.
- Water it in once so it settles and doesn't blow around in the wind. We get some wind up here, especially near the mouth of the canyon, and loose mulch will end up in your neighbor's yard if you don't settle it.
That's it. No fancy tools, no skill required, just the willingness to go get the stuff and spread it, which is exactly why I can't figure out why more people don't do it.
Before next time
Measure whatever bed you're working on and figure out how much mulch you'd need for three inches. Bring that number next week, even if you haven't bought it yet 👍