It’s the end of the season, and we’re all starting to tuck in our garden beds for winter. The soil in your raised garden bed has worked hard all season to impart nutrients to your vegetables and flowers, which leaves the soil depleted. The long winter sleep is a great time to let your soil build back up the supply of nutrients it’s going to need for your plants next year. And rejuvenating your soil now will give you a head start on spring chores.
Leave the roots in place to compost
It’s satisfying to wrench overgrown plants out of your beds at the end of the season, but when you pull out the roots, you’re taking away the part of the plant with the most nutrients. Instead, chop the plant at the soil level and leave the roots in place. They’ll compost over the winter, supplying nitrogen back into the soil. These roots also provide structure in your beds, giving the soil something to hold onto so you experience less erosion over winter.
Plant a cover crop
There are a variety of seeds you can plant in your beds solely for the purpose of improving the soil. They capture water and return nutrients to the soil, leaving it far healthier than would just leaving it alone. You’ll never harvest these crops, which you purposefully don’t allow to fruit, so the nutrients stay in the soil. You should choose a cover crop based on area and need. For instance, if your soil is compacted, you might choose oil driller radish, a variety that is really good at breaking up soil. If you need nitrogen, you might plant fava beans or field peas. Like roots, cover crops prevent erosion too. These plants are generally considered “no till,” meaning that at the end of the season, you’ll just chop them above the surface and call it a day. Your local garden center will have a variety of cover crops you can purchase by the pound at this time of year, and that can help you decide what to plant.
Compost, compost, compost
Your raised bed has lost soil volume over the summer. Some of this is due to compaction of the soil, so you didn’t really lose it, even if there appears to be less than what you started with. But you probably also lost some pulling plants out over the summer. To regain soil volume you need to add mass back in, but what you add is important. If you just add topsoil, you’re not adding nutrients. Adding compost means you’ll get rich humus, which keeps soil aerated and happy. Compost introduces nutrients too, meaning you’re bringing the three essential components of soil—nitrogen, potassium, and phosphorus—back into your raised beds, in addition to trace minerals like calcium, which is essential for tomatoes and peppers. Lastly, adding compost can add structure, bringing with it with lots of worms and mycelium that will make your soil healthy. You can purchase compost at the hardware store, but your city might offer it for free—many municipalities compost leaves and city landscaping and make it available for the public. Landscaping companies also sell compost, and more importantly, deliver.
Mulch with grass and leaves
Right now you’ve got an abundance of two things: leaves. and grass clippings from your last mow. Instead of throwing these in your bins, toss them in your garden beds, which will love them as much as they would mulch. Over the winter, this detritus will provide a safe place for all sorts of beneficial insects, and they’ll eventually break down into compost, which provides all the benefits listed above. Plus, they serve as one last safeguard against erosion.