Compost works wonders in raised beds
by Pamela Doan
A reader asks: I’m making raised beds for vegetable gardening. Can I compost directly in the bed so it will be ready next spring? Getting soil delivered is expensive.
Great choice. Raised beds and compost are a smart way to get a vegetable garden started with nutrient-rich soil. It’s an interesting approach to compost directly in the bed this fall, but there are some challenges.
Your best chance at success is to have the right mix of browns and greens and to layer it now and leave it alone. Don’t add to it. Because we’re on the verge of cold weather, your pile might not get hot enough. It generates heat as the microbes do their work. Starting a new compost pile in cold weather means the materials could freeze and not break down until they thaw again.
Raised beds aren’t very deep. Try to create several small piles with everything you have on hand. For ongoing needs to use vegetable and fruit waste and other compostable materials, consider a winter system that will allow you to reuse everything without impacting the piles that you want to be ready in the spring.
When the ground freezes and the snow starts piling up, I recommend making a simple compost container with a garbage bin.
Drill or cut holes into the sides and bottom for airflow.
Prop it up on a couple of bricks so that air can move under it, too.
Wrap the outside with a screen to keep the critters out if mice and rats are a concern. This is sold in a roll at hardware stores. Use the same screen meant for windows.
Layer greens and browns in the bin and use a pitchfork to turn it. Winter composting solved. You can keep it conveniently close to the house and avoid trekking through the snow.
I also want to address the idea that you need soil brought in to fill the beds. Buying soil can be problematic, as well. Fill dirt can have weed seeds in it, be depleted of nutrients or contaminated even if it’s sold as “clean” fill. Topsoil is typically taken from excavation sites where construction is happening. Be careful when you’re sourcing it, regardless, and ask a lot of questions about where it came from and if it was tested.
Lasagna gardening is a method of layering different materials to create a planting medium. You don’t need anything else. Using this technique, you might be able to fill the beds with materials from your own property. Since it’s fall, you’re in luck and depending on how many trees will be dropping leaves nearby, shredded leaves can be one of your main sources for bed layers and compost.
Leaves are full of carbon and considered a “brown” material for composting. Compost is a mix of nitrogen-rich materials, the “greens” and carbon-rich materials. Vegetable and fruit scraps are “greens.”
The method of lasagna gardening is outlined in a book by Patricia Lanza, Lasagna Gardening: A New Layering System for Bountiful Gardens: No Digging, No Tilling, No Weeding, No Kidding! Instead of tilling the ground for plants, layer materials right on top. I’ve done this and had great results. Materials you can use include compost, peat moss, shredded leaves, manure, straw, wood ash, grass clippings, hay, and sawdust among others.
If you attach wire mesh to the bottom of your beds, it will prevent moles and voles from tunneling up into the beds and stealing your veggies. On top of that, create your bottom layer of mulch with layered newspapers to suppress weeds. Wet them down, then add layers of the materials listed above. One of my beds was mostly shredded leaves, compost and peat moss and it turned into really rich soil. It had few weeds and balanced out at a nice 6.3 pH, just right for most vegetables.
Here’s one last tip for managing fallen leaves. While they need to be shredded to speed decomposition, you don’t need special machinery. A friend shared their method of putting the leaves in a barrel or garbage can and using a string trimmer to shred them in place. Make sure to wear eye protection.