Cabbage Condo

Intro: 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.

STEP 1: Building the Frames

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.

STEP 2: Water-bending PVC Pipe

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.

STEP 3: Securing the PVC Hoops

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.

STEP 4: Ridge Stick

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.

STEP 5: Installing the Screening

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.

STEP 6:

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.

Comments

[xstfoc]

This looks very nice and functional. Is it heavy or cumbersome at all? I was thinking of modifying it, by hinging it on one long side and making a drop down " leg" fastened to the center of the ridge board. That way, you don't have to find a spot to put the cover down after removing it from the lower frame. You would only have to tilt the cover back onto it's "leg" to tend your plants. Do you think that would work okay, even if it means reinforcing/making the ridge-to-hoop connection??? Just a thought. Well done project.

[Bookman14]

I built this out of cedar, so it's really light. You could absolutely hinge one side, and I like the idea of the drop-down leg. I think I'd attach that leg to inside of the other long side, though, rather than the ridge board--

[xstfoc]

But if you attach a leg to the other long side, doesn't that mean the whole top would have to be flipped over onto the ground to put the leg down? It might be even better to put a support leg with some sort of pin (maybe a simple 16 penny nail) on each end so you open the top as far as needed, and adjust the angle of the support leg by pinning the nail through the legs and into various drilled holes in the wooden box frame. Do you think THAT would work the best?

[Bookman14]

Sounds like I misunderstood your idea. I'd been thinking of a single leg, loosely bolted to the center of one long side (see dot in center of long side in first crappy sketch below), so it could swing down. But in drawing this sketch, I realized the angle of the leg would be wrong, done that way. So one or two legs loosely bolted to the SHORT sides (in red below) could swing down and hold the top up while working on plants inside.

Or maybe hinge one SHORT side, then attach a single long leg to the outside of one of the long sides (as in second crappy sketch). The upper frame is light enough that a single leg on one side wouldn't cause much racking stress on the frame.

[xstfoc]

Thanks for the input. I'll mess around with mine as I build it. You know, you can also curve PVC pipe by heating it up with a heat gun or propane torch, you just need to be careful not to entirely melt it. Thanks for listening.

[Bookman14]

Thanks--yes, I'd read about the heat gun / propane technique, but wanted to get a really smooth curve, and bending it on a form seemed the best way to go. I was very happy with the results--no kinks at all in the bends.

[Stevens Workshop]

Really great project, I like how you've iterated the design to best fit your needs. The two lifting methods is also a good addition.

[Bookman14]

The next elaborate upgrade might be to figure out how to hinge the top frame, increase the length of one of the "lifting arms" and weight it--so all you have to do to open the top is push gently down on the weighted arm... but I think I'll see how this does this season first. ;)

[Stevens Workshop]

I can see you tweaking the design every year.
Keep up the great work, hope the food crop is tasty.

[charlessenf-gm]

Love the Ridge Stick idea and execution. I would drill three pilot holes above the opening that the (SCHED40) PVC hopes pass through, then insert screws long enough to pierce the pvc hoop such that it secures the ridge as intended. Alternatively, you could cut three couplings in half, remove a section (1/3 or so) as use them as clips on either side of the ridge board to keep it in place - could secure them with cement or not. pvcfittingstore dot com has some colorful stuff and neat External PVC Couplers. Look for 'furniture grade pvc fittings' as they do make clips for pvc that would work nicely for securing your screening.

[Bookman14]

I'd planned to insert screws to secure the ridge stick in place as you describe, but the bend of the three hoops actually secures it well enough, for at least this first build. I may put them in next year if I need to install new screening.

[BubsyR2]

I learnt some new skills today that I could use in time. Thank you for sharing!

[hrst]

Hi there. This look like the very thing for a budding (intended) gardener like myself. Two questions; Did you notice that the screening had a noticeable effect on the amount of sunlight that filtered through to the plants? Was the structure able to stand windy days? Thanks for sharing this.

[Bookman14]

Though I haven't done a side-by-side trial with plants in and out of the screening, I haven't noticed a difference in plant growth. It seems to me that this lets a lot more light through than spun row covers, too, and those are recommended to keep pests off of vegetable plants.

And this is my first year for THIS structure, but the one I'd built some years ago never blew over, so I'm pretty confident this won't.

[Msbelle910]

love it! would it be possible to pre-drill small holes in the pvc, add connecting pvc to arches and make this self watering ?

[Bookman14]

Now THAT'S a cool idea! I use inexpensive drip hose with emitters every 6", and will bury that under the outer frame--so I won't ever have to lift the top to water. That also keeps water off of the foliage.

But you might be able to rig that up--I'm thinking you'd need to install a T on the straight part of one side of each hoop with a hose fitting on it, then cap both open ends of the hoops. My gut instinct would be to drill holes AFTER bending, because they might either cause the PVC to break or might close up during the bending process. Then there's the issue of position of the holes--you wouldn't want tiny jets of water to dig holes in your soil or batter your plants. Another issue might be rusting the bolts that attach the pipe to the frame--or leaking. If you rig this, please send pix and let me know how it worked!

[shalnachywyt]

Thanks! I've had the same problem with brassicas, but this looks like something I might be able to modify for my own permanent raised beds.

[EloiseCornbuckle]

Great project! Thanks for sharing the pipe/boiling water technique!

[LinnetNC]

I recommend using the grey/electrical conduit type of piping instead of the white plumbing type. It's UV stable and it won't break down after a few years like regular plumbing PVC pipe will. I've been using the same conduit 1" pipes for my hoop houses on my raised garden beds now for almost 10 years.

[Bookman14]

That's a great suggestion, and when it's time for me to replace the screening, I'll use the grey PVC. It'll also be a little less visible than the white.