After having only in-ground garden plots for 8-9 years, last year we decided to add some raised beds to the mix. We took one of our existing 30'x35' in-ground garden plots and converted it to a raised bed plot with 13 metal raised beds. We're so glad we did and the entire family has loved having the raised beds as a part of our backyard garden.
Raised beds are great for smaller plantings when we don't need an entire 30' row of a particular vegetable. While they may not be the best vessels for growing things like watermelons or pumpkins, they work great for mustard greens, cucumbers, squash, and even tomatoes.
They're also nice because they're easy to "flip." I use the term flip to describe the process of removing one vegetable, amending the bed, and planting something else. This is fast and easy with raised beds and can usually be done in a matter of minutes. We just pull or cut the existing plants, add a little Coop Gro and mushroom compost, reconfigure our drip tape if necessary, and get to planting!
Below we'll share some of our experiences thus far and some tips for creating your own raised bed plot.
Are Tall Raised Beds Better?
We designed our raised bed plot with 32" tall raised beds in the back and shorter raised beds in the rest of the plot. We did this to create a staggered or step-down look from the back of the plot to the front. But we often get asked whether the tall beds are worth the extra investment.
I really like the tall beds for vegetables that need digging or that don't get very tall. They work great for potatoes, carrots, beets -- basically anything that grows under the ground. But they also work great for mustard greens and lettuce where the harvesting is done close to the soil.
I think if you're getting older or are limited physically, the tall raised beds are a must. They require virtually no bending whether amending a bed, tending to plants, or harvesting. So if bending is an issue, make the investment with the taller beds and you'll be glad you did.
What Shape Is Best?
Most of the beds in our plot have 12 different configurations in which they can be assembled. We also have four round beds that don't have a variable configuration. We chose to go with a rectangular configuration for most of our beds, but we did use a long, skinny configuration for a few.
We did this because we didn't have enough space to make them all rectangular. We wanted the same amount of space between each bed with enough room to drive a wheelbarrow between the beds. That's why we didn't have all our beds the same shape. I also like the look of having beds with different shapes in the plot.
How to Fill Raised Beds?
This is the question we get asked the most. New raised bed gardeners want to know whether they need to fill the entire bed with good soil, or can they save money by using some "filler" in the bottom of the beds.
We filled our beds with some 13 year old composted wood chips that we found at a local sawmill. They were decomposed very well with no chunks or big pieces of wood. We were able to get a big load delivered for a reasonable price, so that's why we used them.
One thing I've noticed since growing in raised beds is that plant roots grow much deeper than we think. We don't always notice this in the in-ground garden because those roots often break when we pull up plants. But in the raised beds we can often see the extensive root network when we mix and flip beds between plantings.
As a result, I think it's important to use all good soil in a shorter raised bed. There's nothing wrong with using bagged potting soil, but I'd also recommend adding a significant amount of compost. The compost will not only help you create some healthy soil, but it will help the beds maintain moisture better.
For the taller beds, I think you could use some filler in the bottom of those. Some gardeners will fill the bottom with logs and limbs, while others will just use some sorry soil from a dirt pile. But make sure to fill the top half with good soil because your plants will need it.
Do I Need Landscape Fabric?
We didn't use plastic mulch or landscape fabric when installing our raised beds. This is mainly because we were putting the beds in an existing garden plot where the weed pressure was relatively low. I would caution against placing landscape fabric on a lawn and installing raised beds. I've seen grass grow through that stuff pretty quick, and then you've got a mess on your hands.
I'd recommend creating your raised bed plot much like you would an in ground plot. Till the area every couple weeks for two months until the grass is disturbed and unlikely to re-emerge. This will also allow weed seeds to germinate and die each time you cultivate.
If you do this, you won't need to use plastic mulch and you won't have to fight the weeds as much. After installing the raised beds, we used a red wood chip mulch between our beds to provide a nice color contrast and further suppress weed emergence. We still get a few weeds, but it's nothing that is overwhelming.
Plan for Expansion
Maybe you want to eventually have a multi-bed plot like ours, but you're not going to do it all at one time. I'd recommend getting a piece of paper and doing a little dreaming here. Make a map of your dream raised bed garden plot. This will keep things symmetrical and neat as you add more beds in the future.
It will also make irrigation much easier because you can simply hook into your existing irrigation when adding more beds. If you're haphazardly placing beds in any open spaces you have, designing an irrigation system will be tough. But planning ahead will allow you to plug and play as you add more beds.