I did a radio interview a while back in which I babbled for an hour about a bunch of things including the then-imminent construction of the first high tunnel. In that interview, I think I said that I figured it would cost around $600 to build. This comes up now because a farmer-friend, after seeing the finished product, is considering such a structure herself. So this is as good a time as any to set the record straight. Or, straighter, at least.
I’m a decent record keeper but far from an infallible one. After consulting with The Spreadsheet, I came up with a figure of $885 for materials but this did not include the polyethylene cover that I used from my existing stock of materials. Poly is roughly 10 cents per square foot, no matter the dimension. So if you add enough poly for the sides and ends, the total is ~$1020.
Having said that, this tunnel has centre shelving in it for the seedling trays; a significant expense…and one that’s hard to price out after the fact because lumber just kind of gets mixed up from one job to the next. People who use this design for growing out their tomatoes and cukes will not incur this expense or, at least, not all of it.
There’s also the impossible-to-calculate debits and credits for ‘shop supply’; that is, bits and pieces from my existing hardware that I paid for long ago. On the flip side, there are lots of similar things that got charged to the project that I did not use up and which will make future projects cheaper. I also bought a few good quality tools that will be used on future jobs. Conversely, my existing tools – and I think I used ALL of them – experienced wear on this job; that cost was not accounted for.
I bought almost all of the materials from Windsor Plywood, mostly in gratitude for ‘Peter’ finding an appropriate material for the anchor posts. But their prices for that common (in turns out) pipe was about 60% more than I found it for in Victoria (for the big high tunnel I’m currently building) although I needed a whole day, a truck and ferry trips to get it. On the other hand, that Shopping Spree had lots of purchases in which to share the total trip cost.
Windsor’s lumber is also about 15% more expensive than the comparable product at Slegg. Having paid my dues at Windsor, I’ll probably continue to drive the extra 3 minutes to shop at Slegg for the second tunnel. Oh, and Slegg’s hardware – if they have it – is generally cheaper.
There are two significant design changes between the two tunnels. One is the shelving for the transplant tunnel which will not be in the big one. The other is the use of roll up sides on the big one instead of removable ends which I wrote about in my previous post. So far we’ve got $1660 sunk into supplies on the new one plus, say, $220 for the cranks which we paid for a while ago. Add miscellaneous bits and pieces: let’s call it $2000.
The alternative I was seriously considering last fall was the Haygrove system which promises a cost of 75 cents per square foot. The catches? First, that price only applies if you get an acre worth. For the smallest unit that could reasonably fit on the property, I was looking at $9k for 5000 square feet or $1.80/sf. Secondly, shipping was not included and was quoted at $5k. Third, those numbers didn’t include tax. Finally, even if that still made sense, the Haygroves are not rated for snow load. So just for the cost of shipping and tax on shipping of the Haygrove, I can build a large winter-rated high tunnel, a winter-rated transplant tunnel and have $2k left over to invest in Vegas or the stock ‘market’. The square foot cost for the big high tunnel I’m building, including tax, should be less than $1.15.
Plus – and this might be the biggest factor eventually – I now know how to build a high tunnel. Given the proliferation of the 100 mile diet, sustainability, yadda yadda yadda, there may be a local market for construction of these tunnels which could conceivably pay pretty well compared to growing vegetables. If nothing else, it’s something to pass the time in the winter when there’s less to do on the farm (i.e. after all of our own infrastructure is built).