Building Our Own Mini Greenhouses

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With a 70 day growing season, we have to do all we can to extend our growing time.  While our ultimate dream is to have a high tunnel that would provide for all our needs, we know this is simply not feasible for us at this time.

Years ago our greenhouse burned down and we went a few miserable years without one.  Last year we finally had the finances to rebuild it.  Within a week of getting it done, we had some of our severe weather come through and render it unusable once again.

This year we are slowly gathering enough supplies to build a tougher one.  It probably won’t get done this spring.  In the meantime, we are making some mini greenhouses to plant directly into so we can plant sooner and harvest longer.

For this project, we had to use what we had on-hand to get it done.  It’s not magazine perfect, but it will feed us a while earlier and a while later if we do it right (we hope).

We gathered the following supplies from around the homestead:

  • Galvanized steel (that blew off one of the barns a few years back) for the sides.
  • Poles that were left over or kept from the breakdown of other projects
  • 2 x 4s that were left over or kept from the breakdown of other projects
  • Decking screws (because that’s what we had)
  • 1 x 2s that I originally got for trellises
  • Hinges (from a fold-up solar panel that got broken) for one set of doors
  • Hinges (from some old saved screen doors we’d kept) for another set of doors
  • Drill
  • Chainsaw
  • Level
  • Tin snips
  • Clear plastic polyethylene film covering (that was leftover from rebuilding our last greenhouse)
  • Hand stapler


Once we decided where to put our greenhouses, we leveled the ground out with one of the tractors.  We then decided to make our planters 3’ x 9’ and however tall the galvanized steel would make them.

We dug holes for the corner poles and a hole halfway down each long side.  We only buried our poles a foot deep since we knew we would fill the insides of the boxes with dirt, and would have a healthy layer of cinders on the outside as well.

After 6 poles were flush and buried, we cut the steel to length and put them on each side, making sure all these pieces were level.  They were attached with screws.

Building a mini greenhouse to plant right into. If you are not skilled with a chainsaw, DO NOT try this at home; instead cut your posts to length first and then put them in.At this point we cut the tops of the poles as flush to the steel as we could (very carefully) with a chainsaw.  We find with so many of our projects, putting the wood in place first and then cutting saves us a lot of time and effort.

A word of caution
:  if you do not possess the skills to do this with a chainsaw, don’t attempt to do it—cut your poles to size with your regular saw equipment before burying them.  This can be dangerous, and if you nick the steel, you not only harm your chain, but you also risk the saw “kicking” out while it’s running and slicing through whatever it comes into contact with.

See how we made our mini greenhouses that we can plant right into with just the materials we have on hand, costing us $0 out of pocket.After the poles were all cut, 2x4s were placed along all 4 sides, and then we could begin constructing the frame for the doors.

We would have liked to use something bigger for this, but we only had 1x2s available.

We first made vertical triangles for each side, and then two more for the middle of the planter.  A long 1×2 was run along the top.

Once this frame was done, all that was left were the doors themselves.  We made four different doors by cutting our door frames all with 45 degree cuts so perfect 90 degree corners could be made.  Hinges were connected to the inside to attach them to the top frame, and then plastic was run from one side to the other on the left side, as well as on the right side.

We also stapled 4 pieces of plastic to each triangle so that when the doors are shut, the inside is completely closed off from the cool air.

Now that this one is successful, we’ll be making another one next to it as time permits.

Building mini greenhouses from materials on-hand. Now we can plant directly into them and extend our growing season in the spring and in the fall.

Do you have mini greenhouses (or grow boxes or cold frames) that help you extend your season?


Building mini greenhouses from materials on-hand. Now we can plant directly into them and extend our growing season in the spring and in the fall.


  1. Mini green houses sound fun.

  2. Those look so useful!!! Might have to build a couple here for next year. We also have a short growing season.

    • They as so helpful! I was able to get radishes, broccoli, and kohlrabi so far that I would normally have just started planting 5 days ago. I’ll soon have cabbage, cauliflower, and carrots too. I am so glad we built them!

  3. Great article. We own a storage building business, and have had a few people this past year come in asking for pre fabricated greenhouses. This is great. I am daintily going to bring this up to the team. I think it is something that we could do as a community. I am glad I ran into this.

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