What to do with garden be that won’t be used for a year
Thank you for your question. You have a couple of options. One is to cover them with 4-8 inches of mulch, which will suppress weeds, keep the soil from compacting from rain and snow, and break down over time providing ‘food’ for valuable soil microbes and worms, and enriching the soil. The other alternative is to plant a cover crop such as clover, a legume, whose roots provide nitrification to the soil, enriching it as well. They will go to seed, but the flowers will provide nectar and pollen for our pollinators. Upon your return, you can pull out the clover, some of which are viable through most seasons. They, and other cover crops, are described here: https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/fs304.pdf You might try different approaches for your several raised beds to experiment. Hope this is helpful. Bon voyage!
What kind of mulch would you recommend?
I’ve heard of solarizing the soil with a layer of plastic, but we might not have a warm enough climate to do this.
Here is an Extension article comparing mulches. You can combine several kinds. Extension does not recommend plastic for this purpose and for that long. It is a good way to kill soil microbes by depriving them of air and water. It works over a short time to kill weeds or grass if you want to re-landscape. It is even worse than landscape material: https://s3.wp.wsu.edu/uploads/sites/403/2015/03/landscape-fabric.pdf Good luck!