How to prepare raised beds for winter

Asked September 25, 2019, 7:42 PM EDT

Hello, I have 3 raised beds of mushroom garden mix that I grew a variety of vegetables in this summer. I'm planning on clearing them this weekend, and was wondering how to keep them clean for the winter? I have cats and don't want them to be used as litter boxes. Managed to keep them out of the garden when I had seedlings by sticking MANY plastic forks in the gardens. Worked wonderfully! Can I cover the beds with plastic for the winter? I don't have any compost built up yet, just built my tumbler so I can't do that. If covered will they mold? Also, I had some leaf mold issues this season and am wondering if that means I can't use my soil next year? I'm assuming it was the cucumber beetles ( horrible little creatures) that carried and spread it, but does it stay in the soil? My plan was to add compost to the beds next year to use the soil again. Thank you for any advice! ~Melissa Gibbs

Linn County Oregon raised bed gardening

3 Responses

Hi and thanks for contacting Ask an Expert. Yes you can use the soil again. You may need to add more as every season lowers the amount in the beds.
The mold is from fungal spores which are literally everywhere, in the soil, air, on leaves, etc. The rain splashes a lot of spores around until they find a medium they can use for nutrients and with the moisture and the warmth of the season they grow prolifically. I have to laugh as I use plastic forks too. However for larger beds you can use metal fencing (laying it on the soil) with small openings over the winter, chicken wire works and is not too expensive. Cats do not like walking on the metal.
Instead of pulling all your plants out, cut them off at soil level and leave the roots to decompose in the soil giving you some compost for next spring. You can cover your beds with the leaves that fall this autumn and then put the wire over the beds. Nail it down on the corners for easy removal in the spring or put some heavy objects (rocks) on the corners to hold it in place. The leaves will decompose somewhat but not all the way. They will also keep whatever nutrients you have in your soil there (it won't wash out as much as having nothing on top). You can move the leaves to the side and seed directly into the soil, or remove the leaves and place in your compost bin just before you want to seed the beds. Pulling your plants out disrupts the microbial action of the soil, killing microbes needed in the soil food chain.
You could also purchase some green manure or cover crop seeds. You find these at farm supply stores and some grocery stores or nurseries sell them as well. These are seeds that are planted now and grow over winter. They add nitrogen to the soil. Again, in the spring you do not pull them out but cut them at soil level before they flower. They can be added to your compost when cut. Do not add the moldy leaves from this harvest to your compost bin.
The easiest cover crops plants I have found are Austrian pea and vetch. Both are easy to remove and do not grow very tall. A pair of hand pruners will take them out in no time.
I have added a link with more info on cover crops. Depending on the size of your garden beds, you don't need much and it adds greatly to your soil (read the instructions on the package for the appropriate amounts of seed needed). Also when you do not till you keep any carbon that has been sequestered in the soil instead of releasing it into the atmosphere.
When you plant next year if there are still roots in the soil, just plant around them. They will decompose for the most part over the summer.
https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/fs304.pdf
Plastic isn't my first choice because cats like to claw at it and they love to urinate on it.. Cucumber beetles do carry a virus that they transfer but mold spores are virtually everywhere and can be transported in many ways besides rain - on your shoes, your tools by the wind, etc.
If you have further qeustions, please re-contact us..

Thank you so much for the prompt reply and all the helpful information. I'll be implementing your suggestions this weekend.

Have a wonderful fall season!