How often should you mulch your beds?
Grumpty's answer
Every 12 months
Why bother
Thin mulch lets weeds in and dries the soil out. A thorough-tier job. Skippable when life's busy, worth it when it isn't.
Why it's a range
Top up to a couple of inches rather than on a fixed clock. Sunny beds want it yearly, shaded ones can go two.
What the job involves
- Top up, don't tear out. Rake the old mulch to break up any matting or crust, pull the weeds while you're in there so you're not sealing them in, and leave the soil ready for a fresh layer. You rarely need to strip the old stuff.
- Spread shredded bark, wood chips, or leaves to a total depth of 2 to 4 inches. If what's down is still 2 to 3 inches deep, a one-inch top-dress brings back the color and the cover. More is not better.
- Keep it off the bark. Pull mulch 3 to 5 inches back from young trunks and 8 to 10 inches off mature ones and plant stems, with the root flare showing. No volcanoes piled against the wood; that's the one way to turn a tidy chore into a dead tree.
- Water it in lightly so it settles, then check the depth once a year, spring being the usual time, with an optional fall touch-up. It rots down as it does its job, so you're topping up, not rebuilding.
Do it yourself, or pay someone?
Yourself, mostly. Bulk wood mulch is about $30 to $55 a cubic yard (a yard covers roughly 108 sq ft at 3 inches), or about $4 a bag for ~8 sq ft, so DIY runs $15 to $60 a yard all-in. Hiring it out is the convenience tax: full-service install averages around $325 a yard ($210 to $400), labor alone about $0.20 a sq ft. Worth paying for big beds, no truck, or a bad back.
Signs it's overdue
- You can see bare soil through the layer, or it's under 2 inches deep, weeds are coming up through it, and the beds dry out fast after a watering.
- The mulch has gone faded gray, matted into a crust, or started shedding water (rain beads and runs off instead of soaking in). That's decomposed mulch telling you to break it up and refresh it.
- These beds want watering noticeably more often than the mulched ones, and the surface crusts over or washes out after heavy rain.
When to start thinking about it
A few days' warning does it. Grumpty grumbles 5 days out, then leaves you alone. Mark it done and Grumpty sets the next one, every 12 months, so you can go back to forgetting it exists.
Questions people ask
How often do I actually need to re-mulch?
Once a year for most beds, usually in spring, with some people adding a light fall top-up. You're keeping a 2-to-4-inch layer, not rebuilding it: organic mulch rots down, so check the depth and top-dress to suit. Slow-rotting mulch can stretch past a year. No need to do it on a calendar if the layer's still holding.
Do I have to remove the old mulch first?
Usually not. If the existing layer is still 2 to 3 inches deep, rake it to loosen any matting and add about an inch of fresh on top to bring back the depth and color. Only strip and replace it if it's matted into a thick, water-repelling crust or piled up well past 4 inches.
Can you put down too much mulch?
Yes, and it's the one way this job bites. More than 3 to 4 inches, or mulch heaped against trunks and stems, starves the roots of oxygen, traps wet against the bark, and invites rot and pests. Piled into a volcano it can girdle and kill a tree over a few years. Keep the total at 2 to 4 inches and pull it 3 to 10 inches back from trunks so the root flare shows.
Related jobs
Stop keeping this one in your head
This is one job. Your home has dozens more, each on its own clock. Grumpty is a free home-maintenance app: add a job once, it tracks the date, grumbles when it's due, and rolls it forward the moment you mark it done.
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