Last week was a busy one. We replaced both layers of hoophouse plastic and did some running repairs. A mere two years ago we replaced just the outer layer, thinking we had hail storm damage on top where we couldn’t see. Then we suffered from over-zealous snow removal in the winter and made lots of holes in our new plastic. We decided to take it back to the skeleton this time. The inner plastic was 4 years old. Sometimes plastic will last 5 years in our climate.
I’ve written twice on the Mother Earth News Organic Gardening blog about this: How to Put New Plastic on a Hoophouse (High Tunnel): A Step-by-Step Guide and Mistakes to Avoid When Putting New Plastic on Your Hoophouse. I won’t repeat all that info here.
We’ve found that mid-September is the best time of year for us to replace hoophouse plastic. We remove the summer shadecloth early in September, so we’ve got that out of the way. October is our busiest hoophouse month with lots of sowings and transplanting of winter greens. It’s good to get the plastic replaced before then. Also in September the temperature is more moderate. Not too cold, so that the plastic is shrunken, not so hot that it gets overstretched. Mind you, September is hurricane season and we are on the east coast. We watched the forecasts carefully. We were lucky: no big hurricanes came our way, it didn’t rain, and we even chose a week with fairly calm winds. We set aside 5 whole days. The second day was too breezy to fly plastic – more than 5 mph. It actually reached about 9 mph, which I know some of you will still say is not very windy, but people with 48 ft x 100 ft kites have to be careful!
We assembled a crew of five people, and as we always have some new people each year, we arranged to have at least two experienced people present at all times. The first day we removed and rolled up the two layers of old plastic. We’re storing it in case of emergency! We removed the blower hose, the manometer tubing and the two jumper hoses that make sure air flows from the air-intake side of the house to the other (theoretically not needed in our model, which has no pinch-point ridge-pole). We spent the rest of the day removing the crumbling old duct tape that covered all the connectors in the framework, and cleaning out soil that had got in the channels that keep the wigglewire in place along the south and north sides.
The second day was the breezy day, and we made good use of it to finish removing old duct tape and replacing it with new. We used over 8 rolls of duct tape for our 30′ x 96′ house. We had an urgent trip to town, as we had expected 6 rolls to be enough. We found an exterior grade of duct tape, which is a darker, pewter, grey. We’ll let you know in five years how it holds up. It didn’t cost much more than the regular grade. We also replaced a rotten part of the hipboard on the north side.
The third day was calm, and we finished the duct-taping and installed the new plastic. We unrolled the inner plastic along the south side of the house and tied 5 tennis balls into the edge of the plastic, with 60′ ropes attached. One-by-one, we tied a water bottle in a sock to the ropes and threw them over. The inner plastic has a “This Side Down” notice, so we paid attention to that. With the outer plastic, we wanted to pull it over so the side touching the grass would end up outside (ensuring no water or grass mowings got trapped between the layers). Some people are better than others at visualizing how things will be after turning them round!
To our dismay, the inner plastic wasn’t tough enough, and we ended up with three holes up high in the roof, from the tennis balls. We’ve never had that happen before, so I’m left wondering if dripless inner hoophouse plastic isn’t what it used to be. We taped up the holes with PolyPatch tape. We decided to wait till the next day to inflate the hoophouse, as we didn’t want to risk exploding it in the night.
Day 4, we switched on the blower. Golly, it took all day to inflate. So we unplugged it at night and closed the air intake, hoping to preserve the air we’d blown into the space. But the air intake flap was too gappy, so the next day was almost like a fresh start. We trimmed the excess plastic round the edges, tidied away the tools and continued tinkering with getting the right setting on the air intake flap.