Traditional in-ground gardens are great, but there's something to be said for raised bed gardens—it allows you to grow more food in less space, tailor the soil precisely to your needs, and decreases the amount of space for weeds to grow wild. Plus, the soil in a raised bed warms earlier in the spring than in-ground garden beds, so you can get planting sooner. They allow you to garden without fighting stones and roots, and the soil in them is easy to amend each season. With the addition of low tunnels, raised beds also help extend the season when frost threatens.
Of course, there are a few drawbacks to raised bed gardens. In hot dry weather, they tend to dry out quickly. Roaming cats may find the nice, fluffy soil attractive for their own reasons. Plus, you'll want to consider the width of the raised bed when building it to ensure you can easily reach the center when planting or maintaining your garden. (4 feel width is ideal.) However, these few drawbacks are easy to avoid with a little planning and prevention.
Don't Walk on the Soil
The biggest advantage of raised bed gardening is the light, fluffy, absolutely perfect soil you can create. When you build your raised beds, build them so that you're able to reach every part of the bed without having to stand in it. If you already have a raised bed and find that you have to walk on parts of it, consider installing strategically placed patio pavers or boards, and only step on those rather than on the soil.
Mulch After Planting
Plan Your Irrigation System
Soaker hose and drip irrigation are the two best ways to irrigate a raised bed. If you plan it ahead of time and install your irrigation system before planting, you can save yourself a lot of work and time spent standing around with a hose later on.
Install a Barrier to Roots and Weeds
If you have large trees in the area, place your raised bed away from their shade and roots. Most vegetables prefer full or at least partial sun to produce a good harvest. If you want to ensure that you won't have to deal with weeds growing up through your perfect soil, consider installing a barrier at the bottom of the bed. This could be a commercial weed barrier or a thick piece of corrugated cardboard.
If you have an existing raised bed and find that you're battling tree roots every year, you may want to excavate the soil and place the raised bed in a better location. If voles find your garden inviting, try adding hardware cloth to the bottom and up the inside edges of your raised bed prior to filling it with soil. The metal, mesh-like barrier will make it nearly impossible for burrowing creatures to access the bed from below, where they eat the roots of the plants.
Top-Dress Annually with Compost
Gardening in a raised bed is, essentially, like gardening in a really, really large container. As with any container garden, the soil will settle and deplete as time goes on. You can mitigate this by adding a 1- to 2-inch layer of compost or composted manure each spring before you start planting.
Fluff the Soil as Needed
To lighten compacted soil in your raised bed between seasons, simply stick a garden fork as deeply into the soil as possible and wiggle it back and forth. Do that in 8- to 12-inch intervals all over the bed, and your soil will be nicely loosened without a lot of backbreaking work.
Cover up Your Soil, Even When You're Not Gardening
Add a layer of organic mulch or plant a cover crop at the end of your growing season. Soil that is exposed to harsh winter weather can break down and compact much faster than protected soil. Plus, by adding a cover crop, you can increase the soil fertility as the crop breaks down after it's turned into the soil.
Plant Annual Cover Crops
Annual cover crops, such as annual ryegrass, crimson clover, and hairy vetch, that are planted at the end of the growing season can benefit your raised bed garden. They provide nutrients to the soil, especially if you dig them into the bed in spring, reduce erosion, and in the case of vetch and clover, fix nitrogen in your soil.
Create a Pretty, Edible Garden.
Even the simplest raised bed can turn into a pretty destination in your garden. Plan an aesthetically pleasing arrangement of your favorite edibles, pair them with beautiful blooming companion plants to attract beneficial insects to the garden, and you can create a living work of art--and boost your harvests. By adding flowers along the border of your raised bed, pollinators will be attracted to the blooms--helping to pollinate your crops, too, for increased yields. Additionally, beneficial predatory insects will also enjoy the flowers--but will help compact pests in the garden, too.
Think Ahead to Extend the Season
A little planning up front can enable you to grow earlier in the season or extend your growing season well into the fall. Consider installing supports for a simple low tunnel or cold frame, and you'll have minimal work when you need to protect your crops from frost.