Cold weather, snow, thinking about nematodes

We won't starve or get scurvy! Plenty of food in the hoophouse!  Credit Twin Oaks Community
We won’t starve or get scurvy! Plenty of food in the hoophouse!
Credit Twin Oaks Community

This morning we have about 6 inches of snow. Knowing it was coming, we stocked the kitchen with extra potatoes from the root cellar (for those who don’t know, it’s next to impossible to pull a loaded garden cart through loose snow). We also braved the begiinning of the snow yesterday afternoon to harvest some spinach outdoors. We did try digging leeks, but the ground was frozen too deep. If the weather forecast holds true, we won’t see the soil for a week, as not much thawing is predicted. But the hoophouse will feed us. One winter the outdoor crops were inaccessible due to snow, ice or freezing weather, for a whole month, and we were able to feed 100 people in salads and cooking greens from the hoophouse. That wasn’t typical central Virginia weather. But typical isn’t typical any more.

Young blueberry bush in the snow. Credit Bridget Aleshire
Young blueberry bush in the snow.
Credit Bridget Aleshire

Our hoop house is a 30 x 96 ft Clearspan Gothic Cold Frame type from Farmtek. We made ours with bows four feet apart for better strength against ice and snow build up, and the gothic arch shape helps shed snow, as does the rigidity provided by having two layers of plastic and an air bubble. A couple of years ago when we were changing the plastic we added some reinforcement props to the west wall, which was leaning in from the force of winds. On Sunday night I was very glad of that, because we had very high gusty winds, and I lay in bed trying to ignore the sound of the wind, imaging we would lose our hoophouse. Imagine my relief to wake up to see it still in place!

We did have a big pine tree come down near our dining hall, but it missed the big propane tanks and didn’t even block the road by the Tofu Factory. We didn’t lose electric power either, so we have been lucky in several ways. Now I am watching the forecast for Thursday night. At one point the forecast was for a low of -9F, which is unthinkably low! Even the Vates kale won’t survive that – unless we have snow covering, which we still might! Currently the forecast has “warmed” to -2F. We always subtract 5F from the Louisa forecast, because it is often that much colder here.


Meanwhile, here are some warming photos from Hawai’i. Following my article in Growing for Market about dealing with nematodes in the hoophouse, I heard from Gerry Ross at Kupa’a Farms on Maui, at  2000 feet above sea level. (Take a look at their beautiful website, and feel the sunshine!) Root Knot Nematodes are a warm weather problem – they are inactive if the soil is colder than 50F. We had never seen their damage until a few years ago. In warmer climates they may have to deal with them constantly. On Maui the soil temperatures never go below 59F! Their high tunnel is for insect exclusion, not warmer temperatures, so it is covered with insect mesh, not polyethylene.

Nematode-susceptible food crops. Credit Gerry Ross, Kupa'a farms
Nematode-susceptible food crops.
Credit Gerry Ross, Kupa’a farms

Gerry wrote that he is trying a hoophouse crop rotation: “We started with cukes, tomatoes, zukes, and peppers for the hotter summer weather. We then moved to sunn hemp-Piper sudan cover crop for about 45 days, and then to a winter rotation of brassicas with peas and cukes. We will mow and disc the brassicas down in about a month when it starts to get on the warm side and harvest is over and plant directly into the debris with peppers, tomatoes and cukes/zukes. So far we are really pleased with the results…..the brassicas are really clean with no cabbage moth damage. This is just one way to manage the RKN I suspect but so far so good.”

Nematode -fighting cover crops. Credit Gerry Ross, Kupa'a Farms
Nematode -fighting cover crops.
Credit Gerry Ross, Kupa’a Farms

Outdoors, for field crops, Gerry said:

” we usually do 2-4 month cover crop like sunn hemp and Piper sudan grass and then follow that with our most susceptible crops (potatoes, carrots, beans, beets). When those come out we follow with brassicas, lettuce, onions. We usually grow row crops for 8 months in a field and then do a cover crop. The sunn hemp we use is called “Tropic Sunn” and the USDA on Molokai has developed it and bred the alkaloids out of it. Not sure it is widely available but try http://oahurcd.org/ and see if they will mail it to you. We also use vetch as a cover but it can get whacked with RKN so we co-plant with a scaffolding nonhost like the Piper sudan or oats.”

Brassicas in nematode-fighting hoophouse crop rotation. Credit Gerry Ross, Kupa'a Farms
Brassicas in nematode-fighting hoophouse crop rotation.
Credit Gerry Ross, Kupa’a Farms

“Buried in some of the research by the sugar cane companies was a comment that molasses seems to drive down populations of RKN in the soil. We found application of local molasses to be difficult because it is so thick and viscous and hard to make spreadable BUT a local farming store did get us some dried molasses which is used as a horse supplement in the Mainland and applying that to the soil seemed to really help. That might be something you could try.

We have tried lots of compost (food-waste based as manure is not easily available here) and have created beds with loads of earthworms but the RKN persists.
We have found that some lima beans perform well even with heavy RKN infestation esp the Florida speckled butterbeans (huge purple speckled beans on wild vines that live for three years here!) and Fordhook that seem to just carry on regardless of RKN infestation. Fava beans on the other hand suffer mightily and do not produce at all. 
Thank you for the list of remedies and resistant cultivars. We have used the NemaQ and it seems to work if we run through our drip lines or water it in in diluted form in our raised beds. We might try grafted tomatoes too because one of the available rootstocks is RKN resistant. “

So, here I sit with “good garden planning weather” and fight my desire to just hibernate till it warms up!
Field manual Vabf unnamed

Cicadas, transplanting and blueberry netting

Pepper transplants waiting to be set out. Credit Kathryn Simmons
Pepper transplants waiting to be set out.
Credit Kathryn Simmons

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.

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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?

Our new blueberry netting on its hooped frames, Credit Bridget Aleshire
Our new blueberry netting on its hooped frames,
Credit Bridget Aleshire