At last we are getting our warm weather crops transplanted! We finished our 530 Roma paste tomatoes and I’ve just seen this afternoon’s crew of two go past the office window with watermelon starts on a cart. We’re late, but we’re getting there! We have about 260 Crimson Sweet watermelons to go in, and cover to keep the bugs off. This morning, working with the large crew, we set out the ropes and the sticks to hold down the rowcover. Our method is to use the big morning crews to harvest and to get ready whatever will be needed for the small late afternoon transplanting shift, so all they have to do is plant, water and cover. This makes best use of the cooling temperatures later in the day.

After the watermelons, we’ll still have peppers, eggplants, muskmelons (cantaloupes), okra and lots of sweet potatoes to go in. And more lettuce every week.

Meanwhile the brood II 17-year cicadas are in good form. So loud. The ground around the trees is riddled with holes from the emerging juniors. The cast-off shells/exoskeletons are crunchy underfoot. Someone here saw squirrels eating cicadas but I haven’t seen it yet myself.

The other thing I want to write about is our blueberry netting and its seasonal hooped structure. I think this is a good method that more people might like to use. Our older blueberry patch has a rectangular framework made of posts with wires joining the tops. the netting is a fairly rigid square plastic type that is a challenge to put up. This new type is a big improvement – easy to put up and get the netting over, and removable so we don’t have to look at the framework all year.

Our new blueberry area is 16′ x 65′ approx. The height of the netting supports needs to be 7′ or more for most of the space. The 20 blueberry bushes are 66″ apart, in two rows.

We looked at these options, then found a few more:

1. 3/4″ PVC water pipe,
2. 20′ rebar inside PVC piping
3. Fiberglass poles fixed to T-posts
4. Galvanized steel tubing, as sold for small hoophouses.
5. Metal electrical conduit bent into a curve, connected at the ridge.
6. Other tubing, such as chainlink fence top-rail, metal water pipe, curved.
7. “Spider-House” temporary framework
8. Wood-framed structure
9. Bamboo

We chose PVC Electrical conduit. Plastic electrical conduit, unlike water pipe, is UV-inhibited for outdoor use. Lengths have swaged (flanged) ends, so can be joined without any separate connectors. Lightweight, no bending tools needed (unlike for metal conduit or fencing top-rail). Packs flat for out-of-season storage. Relatively cheap.

 We use a “Spider-House” temporary framework – an idea used for temporary “field hoophouses”. It consists of pairs of bows fastened together at the apex, in a way that spreads out into a 4-legged structure. A row of these make up the frame. An advantage is that the spiders are stronger than simple bows, and that the whole thing can be dismantled relatively easily. Helps add strength to lightweight bows.

Blueberry Hoops diagram0001

 I’ll tell you how we did it, then talk about the options we didn’t choose.

• We bought very nice flexible nylon netting from Lee Valley. We chose the 12’ x 117’ ½” mesh, and I stitched two lengths together using nylon thread, making a piece 24’ wide. It should last a long time. It isn’t cheap. It does not ravel when cut, or snag on itself. At the end of the season it can be stuffed in a bag, with just one end poking out of the neck of the bag. Then next year, drop the bag at one end, pull the free end of the netting up over the piping and along the length of the berry patch. Our netting is longer than the patch, but we plan to extend the patch one day. . .
• For our 16’ x 65’ patch, we decided on three “spiders.” Our calculation was that 30’ hooped into a half circle would have a diameter of 19’ (divide circumference by pi to get radius, then multiply by two). So we reckoned having the ends of each pipe 19’ apart, crosswise across the patch. A bit of Pythagoras leads to a spacing along the length of the patch of just over 10’ for a width of 16’ and a diagonal of 19’. We don’t need perfect half-circles, but we did need a rough idea of a workable length.
• We bought 18 pieces of 3/4” PVC electrical conduit in 10’ lengths with swaged (belled) ends.
• We glued them in threes to make 30’ lengths.
• We marked the center point of each length, matched centers of two lengths, then tied a pair of lengths together to form a cross shape. If you were in the scouts, square lashing is the type of knot you need.
• We got 12 4’ lengths of rebar and hammered them halfway in the ground along the long edges of the plot, 12’ 6” apart (six rebars, 5 spaces of 12’ 6” equals 62’ 6”). Close enough.
• We popped the spider legs over the rebar, making sure all the lumpy knots were on the underside of the tubing crossovers, to make it easier to pull the netting.
• When we had all three four-legged spiders in position, we pulled over the netting, and pinned it down every 18” round the edges with 1” wide sod staples/landscape pins.
• We have a doorway along the central seam, simply held closed with clothes pins.

Here’s our thoughts about the ideas we didn’t take up:

PVC water pipe. A small experimental structure at Twin Oaks, made from 3/4″ pipe collapsed in the winter, (but need not have). Cheap, easy to bend, easy to replace. Can install for seasonal use on rebar pieces in the ground (which could be an off-season hazard….). Using PVC glue is smelly and unhealthy. Not cheaper than PVC electrical conduit. See Constructing a Simple PVC High Tunnel by Jim Hail, Robbins Hail, Katherine Kelly, and Ted Carey for a 30’ x 18’ hoophouse from 1” PVC.

There is a smaller design “Portable Field Hoophouse”, using 3/4″ rigid white schedule 40 pvc in 18′ lengths to give a 10′ wide frame for an 18-42′ length hoophouse with no ridgepole.

PEX water pipe tubing: Too bendy

Metal electrical conduit bent into a curve, connected at the ridge. Conduit is cheap and readily available. It can be bent with purchased pipebenders (if the right shape is available), or on a wooden jig, or round stakes hammered into the ground. Lost Creek  sells pipebenders. Johnnys sells Quick Hoops Benders but they make 12’ x 7’ high tunnel or caterpillar tunnel hoops only. They have a video on the site.

Other metal tubing, such as chainlink fence top-rail, or metal water-pipe, bent into a curve. Either use the commercially available pipebenders, as above, or make your own jig. There are good plans by Jamie and Tod Hanley using square tubing, and a home-made bending jig. Square is easier to bend without twisting, but that might not be important for this project.

More plastic tubing (1” x 20’) hoophouse frames and a metal tubing frame as well as photos and details of a bending jig for metal water piping, on the New Farm website, using 3/4″ galvanised piping in 21′ lengths. Their jig consists of 20 short pieces of 2×4 lumber screwed down on the bed of a hay wagon.

Pre-curved galvanized steel tubing, as sold for small hoophouses. Farmtek  has a wide range of ready-made hoop parts, including tall, round-topped styles. Shipping adds to the cost. More expensive than other options.

20′ rebar inside PVC piping. Idea from Cindy Connor for small hoophouses. Stronger than PVC pipe alone. 5/8″ rebar could be used alone (but hard to pull fabrics over).

Fiberglass poles fixed to T-posts. T-posts would stay all year, fiberglass poles stored out of season. Straightforward to do. Splinters from fiberglass could be a problem long-term.

Wood-framed structure. A lot of work, but cheap. Clunky. Might take too long to make.

Bamboo. Free if you have invasive bamboo, but a bit of work. The nodes would snag on the netting. Saw then sand them off? Duct tape?