The most difficult part of gardening, according to some experts, has to do with your soil. “Natural” soil, the kind found around your house, isn’t very natural at all. Before homes are built, contractors usually come in and scrape off all the tops soil — it’s just going to get wrecked when all the heavy machinery comes in and starts digging holes. Then they truck it away. When the foundation pit for your house is dug all the poor quality dirt (not really “soil”) is piled up around your yard. Where I live this “dirt” is all clay. Nothing grows well in clay.
Next, they plop in your house and backfill the dirt. Next they “grade” the dirt away from your house for proper drainage. That’s garden-speak for “they spread the poor quality dirt all over your yard”.
Replacing the Missing Topsoil
If you want anything to grow well you’ve got to buy back your own topsoil (or someone else’s) and put several inches down on top of the poor dirt — but they already graded your yard, so you’ll have to have several inches of the poor quality stuff that you need to have removed first. Sounds like a pain, right?
It is. If you’ve already got an established lawn, trees, and bushes it’s impossible to do without tearing everything out and starting over again.
Make Your Own Soil
To remedy this situation, many gardening experts recommend building raised beds into which you put your own soil. The composition of this soil varies by which method you want to use (Square Foot Gardening, Mittleider method, etc.), but the foundational basis is raising those beds.
Raised beds help not only contain the “new soil” that you make for them, they also keep out the old soil (and any pests that may live in it), and solves any drainage problems that you may have.
How Deep Do Raised Beds Need to Be?
Believe it or not, plants don’t need more than 4-6 inches in which to grow… most plants anyway. Potatoes are one of the exceptions to this rule, and will grow in whatever depth you provide for them (I’ve seen potato towers over 6-feet tall, and LOADED with ‘taters!).
Some carrots and other tap-roots can grow deeper than 6-inches and should be given more depth. Usually anything more than a foot deep is wasting your money — remember, you need to make all the soil that you put into your boxes.
What about berries?
I was recently asked if raised beds were suitable for berries. Yes! Absolutely yes!
What about strawberries? Strawberries only need a couple of inches to grow in. You can even grow them in towers. In most places strawberries come back year after year, so you may want to plant them in other places (I grow mine in flowerbeds as ground-cover).
What about blueberries? As a bush, blueberries want a deeper root system than traditional garden vegetables. Even still, give them a foot of soil, and they should be just fine.
What about covers?
Sometimes you need to cover your beds.
Wind: You might want to do this to keep the wind off them. Wind lowers the temperature and sucks the moisture out of them. If the wind is strong enough it can even tear plants apart.
Sun: If your plants get a lot of sun, they might get too hot and burn — or even die. A cover can help shade them, especially in the brighter and hotter months of summer, or if you want to grow shade-crops in a non-shady garden bed.
Cold: To help keep warmth in you can cover your beds and turn them into a mini-greenhouse. This will help keep in some of the warmth.
Moisture: Keeping plants moist can be a good thing — keeping them too moist can be a bad thing. Covering your beds can hold in much needed moisture.
Although you can build boxes yourself relatively inexpensively, Lifetime Products makes a very good looking raised garden bed that you can pick up at local club store or online. It’s a kit that includes two 6-inch beds that can be stacked together to make one 12-inch bed, and it comes with a zippered cover to help get your plants off to an early start and protect them from the elements.
I’ve been asked if the cover for the Lifetime garden box can be used on other, homemade boxes. I’ve never tried, but I suspect one could fashion strapping or some other method to hold the poles in place (they’re very similar to tent-poles). Of course the company would recommend that you only use the cover with their product, but hey, get creative and see what you can do!