Bye-bye lawn, hello kitchen garden
“A beautiful kitchen garden at the season’s peak can seem like it’s made of a million things. But underneath the overflowing herbs, vining tomatoes and bright flowers are just four key structures. These essentials include raised beds, trellises, borders and pathways.”
– Nicole Johnsey Burke, “Kitchen Garden Revival,” 2020
Last week, I wrote about finding the best location for a new raised-bed kitchen garden. This week, I want to focus on the next steps in the process by focusing on laying out the garden, building and installing the four structural elements of the garden, and filling the beds with a soil mixture that will help the plants thrive.
First, I marked off the entire garden area with stakes and string. We are converting most of a 20-by-25-feet lawn area in the backyard for our kitchen garden, which will include twin raised beds that are 4-by-8-feet with a trellis, and a 3-feet-wide path in between and around the beds set off from the grassy area with a durable border.
Next, I’ll lay down landscape cloth over the grass (I could also remove the grass first if I had the energy to dig more), install the borders around the perimeter of the cloth, and add pea gravel to level off the area and provide good drainage. Another important reason to add gravel is to protect the bottom of wooden raised beds from rotting.
Burke says to calculate the amount of gravel needed by finding the total garden area (17 feet by 14 feet equals 238 square feet) and dividing by 4 to get the total cubic feet (59.5 cubic feet), and then dividing by 27 to get the total yards of gravel needed (2.2 yards).
Once that’s done, I’ll stake out the raised beds to get a good visual of the garden layout so I can make adjustments if needed.
Then it’s time to build the raised beds. I’m using cedar because it’s natural, durable, beautiful and sustainable. It’s not cheap – I spent $450 for 20 8-feet-long cedar two-by-sixes, plus 10 8-feet long one-by-sixes for trim. I also need 1½ -inch deck screws and 1-inch finishing screws to put the beds together.
For the raised beds in our hoophouse, we saved money by buying rough-cut cedar planks that are 12 inches wide; however, for this kitchen garden, we want a smoother look to the beds to match the wood of the surrounding buildings and fences.
It’s important to make sure the beds are level when they’re placed in the garden area; adding more pea gravel underneath the beds in particular spots is a good way to accomplish this.
Once the raised beds are positioned and leveled, the next step is to install the trellis by using a measuring tape to place the trellis in the middle of the two beds and equal distances from the sides of the beds. We’re using a metal trellis that will arch over the pathway in between the beds. It’s a good idea to secure the base of the trellis with gravel at the bottom of the raised bed and/or by staking the trellis.
Next comes one of my favorite parts of creating a new raised-bed garden — filling the bed with soil. There are two options for raised-bed soil: using topsoil from your own land or bringing in topsoil from elsewhere. We don’t have extra topsoil lying around our property, so we’ll use topsoil from a local source.
Burke recommends a mixture of 33% topsoil, 33% compost and 33% coarse sand. The top soil adds structure, the compost adds organic matter, and the sand adds drainage. This mixture creates a fertile sandy loam that provides moisture and nutrients for plants, and is porous enough for air circulation and to allow plant roots to grow freely. We used this mixture for our raised beds in the hoophouse, and I’ve been pleased with the results so far.
To calculate the amount of fill you need for your raised beds, multiply length times width times height to get the cubic feet of each bed (8 x 4 x 2 = 64 cubic feet) and then add the cubic feet of each bed to get total cubic feet (64 x 2 = 128 cubic feet). Divide by 27 to get total cubic yards (128/27 = 4.74 yards). Then divide by 3 to determine the yardage needed for each component of the soil mixture (4.74/3 = 1.58 yards each of topsoil, compost and coarse sand).
I’ll actually need a little less than this because I’m leaving a couple of inches of space at the top of the beds, and I’m filling the bottom with a few inches of gravel to help secure the trellis. (I’ll need to adjust my gravel calculations accordingly.)
When filling raised beds with soil, it’s helpful to protect the rim of the beds with cloth to keep them from getting dirty or marred from the shovel. It’s a good idea to water the soil as the beds are filled to allow the soil to settle before planting. Also, make sure the soil is level in the bed by raking it even.
The last part of the installation work is setting up irrigation (this part needs to be figured out sooner if an underground irrigation system is used beneath the beds). For our kitchen garden, we’re using a drip hose attached to a nearby spigot. Most edible plants need consistent water to produce well, so I don’t recommend hand watering unless you have a lot of time to devote to it.
Now that the garden beds are set up, stay tuned for the really fun parts – planting and growing your kitchen garden.
Rhonda Nowak is a Rogue Valley gardener, teacher and writer. Email her at Rnowak39@gmail.com. For more about gardening, check out her podcasts and videos at https://mailtribune.com/podcasts/the-literary-gardener and her blogs at www.literarygardener.com.
My garden to-do list this week
Prepare kitchen garden area; build new raised beds.
Continue process of sowing seeds and pricking out, potting up and hardening off seedlings.
Plant out cool season seedlings and keep moist (warm weather and no rain in the forecast for the next 10 days). Keep row cloth handy for cold nights.