Cabbage Condo

There's nothing like a garden harvest: homegrown broccoli florets, robust lettuces, fat heads of cabbage! That is, until you get them inside and see that they're riddled with holes and covered in slugs, earwigs and cross-striped cabbage worms, and the broccoli's unappealingly webby. You end up eating only a tiny, untouched core, or throw the whole thing out.

I renewed my interest in vegetable gardening a few years ago, after we'd removed a bunch of white pines that threatened our house here in Massachusetts, and I had real sunlight for the first time in ages. I'd tried spun row cover and PVC hoops pushed directly into the ground, but bugs got under it, and it was a hassle to pull up ground staples, pull back the row cover, then replace it after I'd tended to my plants.

Years earlier, I had built a PVC "hoop house" on a cedar frame, with the idea of setting the whole thing over a group of plants and lifting it off when necessary. It didn't work well because the ground it rested on wasn't perfectly flat, and footprints created gaps so bugs could crawl under the frame easily.

I decided to try hoops again this year, but this time, go elaborate. Rather than make the wooden frame holding the hoops out of horizontal slats as I'd done years ago, I'd turn them vertical, and have a two-frame system—an "outer frame" that would stay in place for the whole season, with a cleat around the inside for an inner frame with the PVC hoops and screening to rest on. This way, no gaps—and with a ridge pole or ridge stick which extended beyond the gable ends of the screening, I'd be able to lift the entire frame off of the plants when I needed to weed or harvest the plants. The hoops would be high enough to give even tall plants like Brussels sprouts room to thrive. Window screening would allow me to water the plants and to see how they're doing without removing the cover, as I had to do with spun row cover.

My choice of wood was Western red cedar for its rot-resistance and its light weight, which makes a difference when you're trying to hoist a large structure by yourself.

• 4' screening (available in 100' rolls online) • 4 10' pieces 1 x 6 Western red cedar for inner and outer frames • 1 10' piece 1 x 6 clear pressure treated, ripped to 4" for ridge stick (remainder was ripped to make strips to hold screening in place) • 1 8' piece 1 x 4" wood for "ridge clamp" (I used leftover mahogany from a deck demolition) • 3 10' pieces ½" PVC pipe • external screws • 8' strap or rope

You may want to build this with different dimensions for your garden, so measurements here are rough.

Cut two 10' 1 x 6 cedar boards into 6' and 4' pieces, then glue and screw them to create a 6' x 4' rectangle, with two 3" external screws going into each corner, and Gorilla glue (indoor/outdoor).

Taking inside measurements from this frame, cut appropriate lengths from the remaining two 1 x 6 cedar pieces to create a second frame that slides into the first (outer) frame with just a little clearance.

Glue and screw a cleat to the inside of the outer frame, its top 1" from the top of the outer frame. Mine was scrap mahogany, roughly 1" x ¾".

The cross-section in the photo shows how the whole thing comes together, with the inner frame resting on the cleat of the outer frame.

I've bent PVC hoops for garden structures before, but merely held them in shape with a wire strung between holes drilled near the ends. The Western red cedar, though light, is also somewhat brittle, and so you don't want a lot of outward pressure on the inner frame which might bend or split it. Videos found online show how you can bend PVC pipe with boiling water. It works surprisingly well.

First, lay out a 4' wide half-circle on a scrap panel of wood, with an improvised compass (a stick nailed into the panel, and a hole drilled 2' from the nail to insert a pencil). Clamp more scraps of wood to the panel, covering the line you've just drawn, and draw another half-circle, on these scraps. Then saw the various pieces to the curve and screw them in place, to act as clamping cleats (if I were doing this again, I'd use beefier scrap wood that would create a solid and complete arc, as well as band-sawing flat surfaces parallel to the edge of the circle, to make clamping easier and more secure).

Next, clamp a piece of 1" PVC pipe in place (I'd already measured the rough height of the hoops I wanted, and cut off some excess). Videos online show people running a piece of thin rope through the PVC pipe and knotting the ends of the rope together to pull the pipe into a hoop (think an archery bow), and that does make the fitting the pipe to the form easier. Insert a cheap funnel into one end of the PVC pipe, and carefully pour boiling water into the pipe, until it comes out the other end. Wait a little while, then refresh the boiling water, continuing for three or four pours.

After a few minutes' wait, tip your bending frame to pour off the water in the pipe, and let it cool. Unclamping the PVC pipe, it spreads out a little, but creates a really satisfying curve which puts almost no pressure on the inner frame at all.

With the inner frame raised on a pair of sawhorses so the hoops can extend below the frame, clamp one of the PVC hoops in place, eyeballing it so that the height looks right, and the bend in the hoop seems centered. Mark the length with a Sharpie, cut the excess off at the bottom of the frame, then drill a pilot hole for a 1/4" hex bolt to hold the pipe in place. Using this first hoop as a guide, cut the other two hoops to length, then clamp them in place and secure them each with a ¼" hex bolt and washers.

Important: with one side of the hoops secured, slide the ridge stick in place before securing the second side of the hoops.

As per the supplies list, rip a 4" strip off of the 1 x 6 piece of pressure treated wood. Measuring off of the inner frame, drill three ⅞" holes about an inch in from one long edge, one in the dead center of its length and one toward at each end, so the PVC pipe hoops will fit neatly in the corners of the inner frame (see drawing).

You could leave the overhanging "handles" plain, but I decided to dress them up a bit by cutting a handle that narrowed towards the outside (see photo). If you hate pressure-treated wood splinters, round over the ridge stick with a router. I used leftover mahogany to fashion a clamp strip, and routed the top and sides of that, leaving the top of the ridge strip and the bottom of the clamp strip flat, to leave as much mating surface as possible for the screening. If you want to be fancy, you could create a tongue-and-groove to really lock the screening in place.

I wanted to be able to replace the screening at the end of a gardening season, or if it got damaged. So the screen isn't held in primarily with staples--it's held in place with strips screwed through the ridge stick and into the inside frame.

Starting with the top, tack-staple two 12' long pieces of 48" wide screen to the ridge stick so it won't slip, leaving about 1" hanging over the center line all along the ridge stick, so it can't pull out easily when you're done with everything. Then attach the top clamp stick with exterior screws every 8" or so. The pressure of the ridge stick and clamp stick keep it held tightly all along its length.

Then it's time to secure the loose ends of the screening. Start by tack-stapling the screen to the top of the inner frame near the center hoop, to establish a taut "mid-line" for the screening. Add several more staples into the inner frame at the corners of the frame, pulling the screening tight. Then apply thin strips of wood to the top of the inner frame, again starting by the center PVC hoop and the corners, then pulling the screening out from between the two and screwing the strip in place to pressure-hold it.

The "gable ends" will be a little trickier--it's easy enough to just gather all of the loose screening up into a bunch in the center of the end side of the inner frame, but if you want it to look neater, create a series of regular folds pulling the loose screening taut over the end hoops. Then place one staple in the top of the inner frame to hold it in place until you can secure it all with another wood strip screwed into the top of the inner frame.

When everything is secured, trim off the excess screening sticking out from between the frame and the strip.

In the end, though the top assembly is light, it's a little awkward to move by yourself. So I attached a piece of thing rope to the clamp stick at the top, which allows the whole thing to be moved from one end--one hand on the wooden handle as a fulcrum, the other as far forward on the rope as is comfortable to do the lifting.

So that's it! I'd thought about running some copper wire around the outer frame, secured with a few screws, because I'd heard slugs won't cross copper. But that seems to be a myth. Looks like my best bet is to run a small line of wood ash or diatomaceous earth around the perimeter of the Cabbage Condo.

Come at me, caterpillars, slugs and earwigs! Give it your best go, and let's see who gets the veggies this summer.