This post by Ann Marie Gardner originally appeared on Modern Farmer opens in a new tab.
Spring has a way of sneaking up on you — it’s only March, but it’s easy to already feel behind on planting. Even if it’s still too early to put spinach in the ground, now is a great time for building raised beds. Jack Algiere, the vegetable farm manager from Stone Barns Center for Food and Agriculture, has these words of wisdom.
Figure Out if You Need a Raised Bed
Raised beds are great in places where the soil is not good or planting in the ground is impossible. Maybe the dirt is too hard to dig up, or you’re planning a roof garden and raised beds are your only option. A raised bed is simply a boxed structure built above the ground and filled with soil. It allows you to plant vegetables, herbs and plants without deep root structures.
Prepare the Area
First up: Engineer the space beneath and around where your raised bed will go so the area will have drainage. You can do this with crushed stone or gravel that will allow water to go all the way through and out. Excess water has to drain, or the roots will suffocate and the plants will drown. The beauty of raised beds is that they are controllable environments; you can eliminate weeds and create the exact space you want to grow what you need. Layer landscape fabric or even old newspapers on top of the gravel and underneath the soil to keep the dirt in place. This layer also acts as a weed barrier.
Choose Your Materials
When it comes to choosing your bed’s materials, you need to make decisions about two major elements: stackable joints and the frame. Stackable joints connect to the frame to help support and sustain the bed’s shape, and can be made out of stone, metal, logs or whatever you feel comfortable with.
For the frame itself, Algiere prefers the “cleanness” of a wooden one. But avoid cedar; its oils inhibit root growth. Also, pine and Douglas fir won’t last; they’ll rot quickly. Hardwoods like locust or white oak have the most durability and longevity.
Algiere’s recommended frame dimensions are as follows: 5 feet by 12 feet, with a depth of 2 feet and height of 24 inches. If that seems too high, 12 inches also works.
You’ve got the beds built. Laid gravel and fabric. Now it’s time for the soil.
Treat this raised-bed box like a pot, and fill the whole bed with soil. If you want to screen the soil, you can put heavier topsoil on the bottom, thinning it as it gets closer to the top. You can also put potting mix into raised beds, although it’s expensive and its longevity is not as good as topsoil. But do not fill the bed with only compost, as that is “way too much” organic matter.
The ideal time to add compost is after you plant. Work it into the top 6 inches and add to it regularly over the years.