Notes from Windward: #66


Winterizing Vermadise

exploring ways to extend the season

     Vermadise got its name by virtue of it being a greenhouse that's optimized for the growing of earthworms both as a soil enhancement and as a way to produce protein to be used in the on-site production of feed for our fish and ducks. As such, it's designed as a passive structure that will function without supplemental heating during the winter as the earthworms go dormant.

     That being said, the more heat we can retain inside Vermadise, the more active the earthworms will be and the shorter the dormant period, but it's important to remember that the challenge here is first to insure that the earthworms, rabbits and such don't over heat in the summer, and that retaining heat in winter is a secondary goal. The primary way we accomplish that is by using a plastic retaining system that allows us to easily remove the plastic cover in June when the summer heat sets in, and the replace it in late September once the danger of overheating is past.

     Now that we're getting hard freezes, it's past time to finish Vermadise's southern end so that it can retain the day's heat into the night. The goal here isn't to keep the inside warm, necessarily, but rather to moderate the temperature difference between night and day.

     The basic structure is made from one and a half inch diameter galvanized steel pipe, so in order to attach a plastic wall to the southern end, we had to first clad the pipe with wood.

the top arch with its wood facing


  November 5:

     We had hoped to have the rest of the Lexan installed on the southern end of Vermadise by now, but it's been raining pretty steadily for days now, and there's not much point in taking the risk of using power tools when it drizzling outside--in due time the rain will pass, and so we've been tending to inside work for the most part since there's lots of things than still need attention before we're ready for the first heavy snowfall.

installing an indoor and outdoor temperature and humidity monitor in Vermadise

     Down the road we look forward to extending a WiFi web throughout the main area so that we can monitor our various systems around the clock and check up on things such as the amount of water in the main tank or the status of the aquaponics systems from any of our computers, but we're not there yet. And so, we'll continue to use local readouts to gain information on how our systems are functioning. In this case we're very interested in what sort of thermal differential we'll see between the outside temps and the temps inside of Vermadise once we finish getting it sealed for the winter.

installing the keel pole supports

     Working inside Vermadise on a rainy day is quite pleasant since it's quite light and open inside, so a good rainy-day task for the day involved cutting and installing keel pole supports. Vermadise is formed from a series of twenty-foot wide arches made from one and a half inch galvanized steel pipe. Each arch is kept in position by a keel pipe that runs from one end to the other, a function which is very important when a wet snow puts a serious load on the roof and each arc has to stay in place if the roof is going to bear the snow load.

     Since we've added to that load by suspending ninety feet of grow tubes from the keel pipe, we felt it was prudent to install some 4x4 supports in order to insure that the combination of grow tubes and damp snow didn't exceed the arch's carrying capacity.

  November 8:

     The "Pineapple Express" continues to pound away--that's the local name for the weather pattern that brings tropical moist air straight from Hawaii to the Cascade mountains where it falls as a week or more of steady rain. Since we're just on the leeward side of the mountains, we only get about half the rain that folks west of us receive, but half of a heck of a lot of rain is still a lot of rain. Today the Klickitat was running high and muddy with the runoff--fortunately there's no snow for the warm rain to melt or we'd be looking at flooding for sure.

the south end of Vermadise with it's Lexan covering

     That isn't to say that there haven't been entire hours this past week when it stopped raining, and indeed one day we even had a couple of hours of sunshine, so here and there we've been able to keep going forward with the process of winterizing Vermadise. The Lexan we used to cover the southern wall was expensive, but it sure is a delight to work with--it's definitely a material we're going to want to use whenever we can.

sealing off the work room

     It turned out that we had enough Lexan left over to be able to use it to cover the two spaces on each side of the door between Vermadise and the work room. That's really nice since it will allow in enough light so that we will be able to see to work in there without needing additional day time lighting.

one of the edge gaps that needs to be sealed

     Since Vermadise is a passive structure (i.e. it won't be heated other than by sunlight), we'll want to close up any gap that allows the sun-warmed interior air to escape. The above pic is an example of the sort of gap that we'll want to seal before the really cold weather comes.

the last of the end wall sections sealed

     During a break in the rain today we were able to cut and install the last bit of end wall (the plywood triangle to the left of the pic above) to the north end of Vermadise, so that part of the project is completed. Even without that panel in place, it was four degrees warmer inside of Vermadise than outside, a differential which we hope will increase as we track down and close more places where warm air can escape the building.

  November 12:

     More rain on and off today, so it was another good afternoon to work inside Vermadise continuing the process of sealing up all the various openings that allow the sun-warmed air to escape. The work has progressed to the point where you can really feel the air moving through the openings that are left which makes for a satisfying sense of "closure" when they're closed off.

the south-eastern corner closed up

  November 14:

     Today saw the last of the panels mounted into place in Vermadise, so now--with the very notable exception of the door between Vermadise and the work room--I'm ready to consider Vermadise sealed for the winter. Actually, we'll invest a canister or two of expanding foam to seal up things a bit tighter, but those gaps won't matter until we get the inner door in place. The Plan is to track down some sort of used door that is primarily glass so that light from Vermadise will illuminate the work room.

the final sections mounted in place above the door frame

     Now that Vermadise is, for the most part, sealed, Gina brought over some lettuce seedlings to plant in the grow tubes as part of our goal to use Vermadise to extend our growing season.
Gina transplanting lettuce into the grow tubes

Notes From Windward - Index - Vol. 66