How to Make a Raised Bed Garden

Suburban gardeners looking for more space need look no further than the front or back lawn. There’s nothing wrong with having a lawn, but they are water guzzlers and, face it, most of us use very little of it if any at all.

Some of you may think of this as the ultimate sacrifice, and some of you may be relieved that someone finally gave you permission to have something other than grass in your front yard. In any case, it can make sense to take a little bit of the green carpet and use it for flowers, food, or both.

There are several ways to make a raised bed on the lawn, but this is my favorite way because it also happens to be the easiest. At the end of summer or early fall, I make way for a new garden bed by making what I call a “compost sandwich.” It’s also called sheet composting, and some loosely use the term “lasagna gardening.”

In reality, this isn’t true lasagna gardening because with this technique, you’re actually waiting until the following spring to plant the beds. Therefore, the organic matter in the beds will have already composted (for the most part) by the time you plant. Usually with lasagna gardening, the beds are planted right after the layers are created; that is, before everything breaks down into compost.

The reason it’s a great idea to start a garden bed off as a compost sandwich is because it ends up with excellent water-holding capabilities — making terrific use of the winter rainfall. It’ll have very few weed problems. If weeds do occasionally appear, they slide easily out of the crumbly soil. Best of all, it’ll be pliable, nutritional, and ready for spring seeding.

What you’ll need:

All kinds of cardboard — keep pizza boxes, cereal boxes, and so on, to have a collection

Newspaper

An assortment of carbon materials (“browns”) such as leaves, straw, weedless grass hay, newspaper, shredded bark, shavings, and so on

An assortment of nitrogen materials (“greens”) such as grass clippings, vegetable
peelings, seedless weeds, perennial plant clippings, coffee, tea bags, and so on

Topsoil or garden soil

Manure from herbivores (chicken, rabbit, horse — no dog or cat poop)

Water

What you’ll do:

1. Start with covering the entire garden area with cardboard, corrugated or whatever you have.

2. Next, take some newspaper and lay it over the cardboard. You’ll want to make this layer about 2” thick, if possible. Don’t get a ruler out — it doesn’t need to be exactly 2”, just make a solid layer. Have a hose nearby to water in between the layers to get everything moving toward decomposition.

3. The next layer you’ll add will be a green — whatever green your heart desires, but if you choose grass clippings, keep the layer thinner as the grass seems to compact and not let air inside.

4. Next, you’ll spread a manure layer, and then a thin layer of topsoil. At this point, you’ll go back to your carbons; maybe this time you’ll use straw instead of newspaper. You can also go back to newspaper.

I can’t stress enough that composting of any kind is an art — not rocket science. While there’s certainly a basic chemistry to it, you don’t need to measure and get precise. Make your sandwich the best you can and use varying materials while creating.

5. Make as many layers as you can, switching between the browns and the greens, manures, and the topsoil. Don’t stop until you run out of materials, even if the pile is higher than the bed; it won’t be for long.

6. The last layer will be topsoil.

Be sure to water between the layers while you’re building the sandwich. You’re not trying to flood it, but the sandwich needs to be wet. Water the last layer of topsoil. Now, other than watering the sandwich if you have dry weather, leave it alone. Don’t do a darned thing to it all winter. You’re going to be so thrilled with the soil in your new bed next spring.

Now, if you were to build this sandwich in the spring, be sure to add quite a bit more topsoil into the layers and maybe some peat moss for good measure. You could plant it with veggies right then and grow a garden while everything is breaking down. The plants would do great — but next year’s crop would do even better.

Also, if you do plant in the bed before the organic matter has broken down, it’ll tend to rob some of the nitrogen from the soil that was there to begin with. So you can add extra greens to combat this, such as bone meal or grass blades.

Tip Thyme

If you’re an alpine aficionado, there’s no better way to show them off than in a raised bed where their intricacies can be appreciated.

Reprinted with permission from The Complete Idiot’s Guide to Small-Space Gardening by Chris McClaughlin and published by Alpha Books, 2012. Buy this book from our store: The Complete Idiot’s Guide to Small-Space Gardening