How should I remove moss from my raised beds?


I had a quite a lot of moss growing in my raised beds. I’m sure the heavy rain didn’t help. I am going to get the soil tested. What is the best course of action for the moss—remove it or dig it under?


Jonathan Foster, Home Horticulture Outreach Professional

You’re absolutely right that your first step should be a soil test through the UMaine Analytical Soil Laboratory–you can request kits and get instructions for how to take the sample on their website, if you haven’t done it before. Moss in and of itself isn’t necessarily a negative thing in the garden and this year’s heavy rainfall no doubt contributed (as you suggest), but it does often serve as an indicator of potential underlying soil problems. Acidic soil, compacted soil, overly wet soil, and soil low in organic matter all help moss flourish, and all inhibit the best growth of your other common garden plants. You will probably get results back that your soil is a bit too acidic, and you’ll need to carefully add lime to raise the pH and annual doses of compost to boost the drainage, the structure, and the fertility, but don’t do any of that until you actually get the test. We don’t want people adding amendments to their garden unless they know their starting point and what specific deficiencies there might be; otherwise, you’re spending money and effort on guesses.

As far as what to do with the moss itself, if it’s already dead and it’s not a big, thick carpet, I would say you can turn it under, but if it’s still green you should probably toss it into the compost to let it break down. It’s a perfectly safe addition to your soil (in fact, composted moss improves aeration, water retention and drainage, and soil texture), but too much green plant material turned directly into your soil can lead to nitrogen problems as decomposing microorganisms work away at it… and we’re already slightly suspicious of the soil chemistry in your bed!