Raised beds are great: the soil in them warms and dries out earlier in the spring than regular garden beds, so you can get planting sooner. They allow us to garden without fighting stones and roots, and the soil in them stays perfectly fluffy, since it doesn't get walked on.
Of course, there are a few drawbacks: in hot dry weather, raised beds tend to dry out quickly. Roots from nearby trees will eventually find their way into your nice, nutrient-dense soil. Roaming cats may find the nice, fluffy soil attractive for their own reasons. But these few drawbacks are easy to avoid with a little planning and prevention.
Ten Tips for Raised Bed Gardening
Don't ever -- ever! -- walk on the soil.
The biggest advantage of raised bed gardening is the light, fluffy, absolutely perfect soil you're able to work with as a result. 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 that rather than on the soil.
Mulch after planting.
Mulch with straw, grass clippings, leaves, or wood chips after planting your garden. This will reduce the amount of weeding you'll have to do and keep the soil moist.
Plan your irrigation system.
Two of the best ways to irrigate a raised bed are by soaker hose and drip irrigation. If you plant it ahead of time, and install your irrigation system before planting, you can save yourself a lot of work and standing around with a hose later on.
Install a barrier to roots and weeds.
If you have large trees in the area, or just 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, a piece of old carpet, 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 have to excavate the soil, install the barrier, and refill with the soil. It's a bit of work, but it will save you tons of work later on.
Topdress 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 get depleted as time goes on. You can mitigate this by adding a one to two inch layer of compost or composted manure each spring before you start planting.
Fluff the soil with a garden fork as needed.
To lighten compacted soil in your raised bed, simply stick a garden fork as deeply into the soil as possible, and wiggle it back and forth. Do that at eight to twelve 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 (read more about that below) at the end of your growing season. Soil that is exposed to harsh winter weather breaks down and compacts much faster than protected soil.
Plant annual cover crops.
Annual cover crops, such as annual rye grass, crimson clover, and hairy vetch, planted at the end of the growing season, will provide many benefits to 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 cas of vetch and clover) fix nitrogen in your soil.
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!
Consider composting directly in your raised bed garden.Worm tubes, trench composting, and dig-and-drop composting are all methods you can use to compost directly in your raised bed garden. You'll be able to enrich your soil without ever having to turn a compost pile.