Raised Vegetable Garden Beds Covered by Moss

(Question)

Hi, I have been growing vegetables in largish raised beds for a bout 15 years in north Caledon. Several of the beds grew masses of moss last year and they are still there after the winter. Should I just turn these into the soil and use for green compost or ignor them or??? Thank you for your time. Gayle Olsson

 

(Answer)

 

Turning the soil under will not harm most plants but “may inhibit the growth of small or young plants.” If you decide to remove the moss and compost it, be aware that moss decomposes slowly so mix it at a 1:4 ratio with other ingredients. Either action will deal with the existing moss but to prevent it from recurring you should make changes to remove its preferred environment.

Mosses are shallow rooted, acid loving plants that can grow in part to full shade. They prefer a pH of 5.0 – 5.5 whereas vegetables grow best at a pH closer to neutral 6.5 – 7.0. Because they are shallow rooted, they thrive on compacted soil with poor drainage. I suggest that you test the pH of the soil in the beds to see if it has become more acidic over the years. Has the soil also become compacted?  One of the advantages of using raised beds  is that they are not stepped in and digging is minimal. In fact, adding a good layer of compost helps to keep the soil loose. I personally let the earthworms from my compost aerate the soil in my raised beds.

Since you have been using these beds for some time but the moss appeared last year, has anything changed? Are the beds getting less sun due to growth of nearby trees? If so, judicious pruning may restore the amount of sun on the garden. Was there more rain last year that encouraged the growth of the moss? If your soil is clay based, the water will not drain as quickly. You may have to add some drainage so that water doesn’t sit on the soil. I have included a link to a site with a bit more information on mosses.