Home Gardening When a Greenhorn Builds a Greenhouse

When a Greenhorn Builds a Greenhouse

When a Greenhorn Builds a Greenhouse

Hooping It Up With a Greenhouse Down on the Farm

high tunnel hoop house greenhouseSun Island Farm’s hoophouse: similar to what mine will look like.

About a year ago, I applied for and received (after some time) a cost-share grant to build a high tunnel hoophouse, a greenhouse-like structure framed with steel tubular ribs and covered in a UV-resistant plastic. Its purpose: to extend the growing season in spring and fall, and in the case of some crops, through winter as well. A little more sun and a little more heat can do wonders for both soul and seedling here in the Maritime Northwest.  I may just put in a wading pool, spread sand, add a chaise lounge and palm tree, and rent the space by the hour.

As I’ve never grown anything in a covered space before, I’m plowing through some unknown territory here, but I can assure you that I’m up for the challenge.

greenhouse interior look at high tunnel constructionInterior view of Sun Island’s newly built hoophouse, I’m guessing the warmest spot of Vashon Island.

Let me introduce you to the concept. Hoophouses, or high tunnels as they are also known, trap heat much like a car windows do on a sunny day. The plastic sheeting inhibits air circulation and flow, trapping energy in the form of heat within its walls. Plants are usually planted directly in the ground, and pampered to grow up big and strong without the threat of pests and inclement weather. greenhouse component of high tunnel hoophouse Because the hoophouse can get too hot, sides are designed to roll up, and let fresh air in and over-heated air out. Shown from left to right: the roll-up wall lowered and secured, the manual mechanism to roll a 72-foot wall of plastic sheeting up and down, and the wall rolled up about six inches above the base board.

greenhouse high tunnel hoophouse sliding doorThe end walls sport a sliding barn-style rigid plastic door to allow tillers, tractors, sun and farmers access to the space. The soil in this hoophouse has yet to be cultivated and prepared for planting.

Sun Island Farmers, Joe and Celina, were wonderfully generous in sharing their hoophouse expertise and letting me drop by repeatedly to study their structures and building techniques. Though often referred to as a hoophouse kit, I’ve come to believe the term kit is aspirational at best; hoophouses are as custom and idiosyncratic as the farmers who build them and the land where they are placed. No two are exactly alike.

pickup truck bulldog on a load of lumberBig load: Tom pushes his luck, while Boz (yet again) tempts the scientific laws of balance. 

Naively, I thought building this structure would be a piece of cake. My willing spirit was sucker-punched by my aching body the first day–a day which simply required moving all of the steel pipes, boxes and parts up to the staging area.

greenhouse construction zoneOf the 26 anchor posts to be pounded down to a depth  of 30 inches, 24 found large granite rocks on their way, impeding my sledge-hammer wielding mastery, progress, and hope to have fully functional arms at the end of the day. Frequent breaks and whining kept me going.

greenhouse structural steel skeletonFour days later, and the super structure is up with base boards and roll-up supports bolted into place.

What’s the next step?  I need to build end walls and doors, add channel lock to keep the sheeting in place and oh, yeah cover it with plastic. That’s all. Stay tuned for the next episode of When a Greenhorn Builds a Greenhouse.

Special thanks to Bernie, Karen, Rick, Tamara, Joe, Celina and Jon for your help. Without it, I’d probably be in traction, and my hoop house would look like this.

rusted scrap metal


  1. Oh, Tom, my joints ache for you, but this is such an impressive undertaking. Let me know when you’re ready to sell tickets for that lawn chair cocktail party, sounds like the ultimate retreat this snowy spring.

    • MA get out your party dress, I do believe a christening will be in order and take place in this structure which you can already guess will be warmer than my house.

  2. *Passes Tom some virtual Ibuprofen and an ice pack* Looking awesome so far, Tom! I’m sooooo jealous. I wish we had that much flat ground, I’d love to have a couple of these! Can’t wait for the next installment!

  3. Good job Tom! I am sure you will use every inch of this space! I so enjoy my little greenhouse here on the east coast of NC. It has paid for itself many times over by starting all my plants from seed in late winter/early spring. Only use mine in winter to keep my tropical potted plants from freezing. I tried growing tomatoes the first winter and had a few, but figured they cost around $20 each from all the energy it took to keep it warm enough so they would grow! You on the other hand, have so much potential here with this large space! My old girl “Blossom” used to love to use it for big jobbies if it was raining or cold. She really thought it was her very own “out house”!

  4. Tom –
    I could have saved you some $$$ on your perforated pipe and other materials in you pictures! Next time you are doing a project of this size, let me know your materials needs as I can save you a substantial amount of money!

  5. I am so happy for you! You’re going to have quite the greenhouse when it is completed…and I am definitely glad you have HELP! I don’t think this would be a one-man-project! 😉 What fun you will have harvesting good things to eat…

  6. Hi Tom,
    Are you building that on Vashon? It looks great so far. We’re putting one up too–the ‘kit’ arrives on Thursday. But it suddenly occurred to us that we might need a building permit. Did you need one? The tribulations associated with pounding that many posts will be a good reality check for my husband :-). Look forward to finding out how the rest of the project goes!

    • Hi Mandy, I am building this on Vashon and from what I’ve researched with the county and from what others have told me too, the hoophouse is a temporary structure so you don’t need a building permit. Now if you move into and dig a pool, that may be a different story. Good luck! Today we’re putting on the plastic–layer one.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.