By Pam Jones
Master Gardener Volunteer, Allegany County Cooperative Extension
Even though it is still too hard, and in some areas too wet, to dig a bed, you can still decide how large you want the bed and where it will be to be located. You can also construct a raised bed in your shop or basement.
Making the frame for a raised bed—(If I can do this so can you)!
1. Decide how large you want the bed to be, and what shape. I have round ones as well as oval, triangular, rectangular and square. If this is your first one, you probably want to do square or rectangular frame.
2. Decide on the material for the frame. I have done wood, bricks, plastic, and the solid concrete blocks used for walls. My first bed was round with blocks that were 12” high x2.5” thick and 4” wide and sunk 9 inches in the ground to keep weeds out. I would never have done this if my husband had not helped me, and I do not recommend it. It was hard digging the trench for them and even 9 inches deep did not keep the weeds out. Because Jim was an engineer he had calculated the circumference based on the block size and none had to be cut. My math skills are not up to that!
3. If you use blocks or bricks, ask when you buy them if you can bring one or two back to be cut. If you have a space where a full block/brick will not fit, you will need to cut it or have it cut. I mark mine with a ruler and marker and take them back where I bought them and they cut them for me. Dig a trench and lay the bricks into the trench, mounding the soil along them to keep them straight.
4. For wood or plastic, decide the dimensions of the bed and cut the material to fit. You can use pieces you have or buy new ones. I have used both plain wood and the newly treated ones, without the arsenic. Boards should be 6 inches or more wide and 1-2 inches thick to last. Butt one side to the second side and screw the two pieces together in at least two spots. If you are using oak or another hardwood, you will have to pre-drill holes, if the wood is pine you do not need to pre drill. I like galvanized or stainless steel screws. Repeat with the remaining pieces. Alternatively, you can get iron brackets and instead of screwing the two pieces to each other, you screw them into the brackets instead. These are L-shaped brackets. Don’t be cheap and try to use something like perforated hanging straps to secure your boards. It does not last and you will have to rebuild the frame in a couple of years. If you used wood and have reached the top of your frame after a few years, you can get either long bolts and bolt another board on top of the original frame or use metal plates to secure the top and bottom boards together. If you think you will want to go higher, it is easier to go higher as you first build than to add on later, but it can be done.
5. Dig a trench 1-2 inches deep and set the frame into the trench. If you don’t want to dig down, you can put layers of cardboard on the ground to smoother the grass and weeds and place the frame on top of the cardboard and add soil on top of this. I personally dig the trench and then I remove at least half of the soil and replace it with good soil that I buy. It is available at most nurseries. Then I add compost and ground leaves to the new soil and fill the frame. Now you are ready to plant. You should test your soil to see if there are any nutrients missing and to see if the pH is correct for what you want to grow. This is best done in fall, but you could add a balanced fertilizer this spring if needed. Next fall, take your soil to one of the Cornell Cooperative Extension Soil Testing Clinics. In most counties the first two samples are free. There is a small fee for more samples. Before putting in ANY PLANTS – but after building the raised bed and filling it with soil – test your soil and find out how much sulfur needs to be added to get the pH to 4.5. The soil needs to be at this level BEFORE any plants are put into the ground and this may take 1-2 years to get the soil acidic enough with multiple applications of sulfur.
Along with a new bed, you may want to think of a different way to grow some of your plants. Rebar or round stock make good long lasting trellises to grow beans, peas, cucumbers and squash vertically. You could also buy a pre-made wooden trellis for this, depending upon your carpentry skills. If you have a small yard this gives you extra room for other things. I know people who grow melons on trellises too – remember that our growing period is limited so pick a variety that will have time to mature before the first frost. Consider also the weight of the squash/melons – you don’t want a variety that is too large or they may break off the stalk when hanging from a trellis. If you just HAVE to have a variety that takes a long time to mature – get the seeds started indoors early and then transplant into your raised bed.
Now that I have your imagination going wild – start building those raised beds!