Archive for the ‘greenhouse’ Category

Greenhouse Re-do

Five years ago I built a little greenhouse outside my basement door and thousands of mostly happy little plants have been grown in it since then.   The chronicle of the project is here.   I had to make it narrow to fit the available space and that has always been a problem, principally because the widest door I could fit into it was 22 inches wide — not good for getting any bulky items in and out of the basement.  Also, I had added a sort of bump-out on the side of it to get more room, which it did, but that bumped up the ugly factor a little more than I could stand. I’m no longer growing flowers for the local farmers’ market, so I don’t need as much room as I did.

The old structure was 5′ x 10′, and by digging some dirt out on one side, I was able to stretch it out to 6.5′ x 10′, and raise the height to almost 9′ at the peak.

new 1053

I was able to re-use the base sides and braces and make longer end pieces.

new 1054

Only five frames this time instead of six.  That gives 30″ OC spacing, compared to 24″ before.  It turns out that snow load is not a big problem because it’s easy to knock the snow off from the inside.  There’s no big buildup.  The sides are also taller.  I was able to salvage the plywood gussets and the two by fours for the roof from the old greenhouse.

new 1056

Frames are up with longitudinal and diagonal braces — screwed to the base and to the house.

new 1057

Showing my $20 storm door from the Habitat For Humanity ReStore.  It’s 36″ wide (yippee) and is a way better door than the one I made for the original house.

new 1060

The old greenhouse shelving used something called metal lath, which I thought would be great because water and dirt would just fall right through.  That was actually a good idea, but the stuff had sharp edges and I poked holes in the bottoms of too many plastic plant trays.  Holes in trays were OK for greenhouse use, but not for in the basement where the seed starting happened.  This time I decided to rip salvaged two by fours into slats and staple those down.  I think I’ll like it better.

new 1061

The right-hand shelf has a little warp, the result of using lumber salvaged from the first greenhouse, but what will that hurt?  Nuttin’, Honey.  I hadn’t noticed it until I looked at this photo.

new 1065

And here it stands.  Along with ten two-by-fours, I did have to buy some new plastic, due to the bigger size and the fact that the old plastic was five years old, one year past its stated lifetime.

A couple of details:

I used aluminum channel and wiggle wire to fasten the plastic to the wall corners and gable ends.

new 1066

To seal the greenhouse to the siding of the house, I put duct tape on the siding and used foam to fill the gaps.  The duct tape was to keep the foam from sticking to the siding.  Someday, I will be moving the greenhouse and I don’t want to have to do a lot of scraping then.

new 1075

Just for fun, I made some comparison pics, the original greenhouse on the left and the new version on the right.


As I write this in northern Michigan, we are having a rare sunny November day and the greenhouse thermometer is reading 100 °F.  I wish I could say that will last.


My Homemade Greenhouse

I just finished building a small greenhouse that I plan to use for plant starting in the spring.  I think I overbuilt it a bit, but I was concerned about the snow buildup this winter.

I started with a frame of pressure treated 4 x 4s and beveled them on the end because I plan to drag the greenhouse to another location next summer when I’m done with it.

Base with corner braces

Base with corner braces

Base with beveled end, the better to drag it

Base with beveled end, the better to drag it

I decided to go with a 12/12 roof pitch to help shed snow and five foot sidewalls to give me just enough headroom in the center.   After cutting thirty-six plywood gussets, along with studs and rafters, I laid each set out on my basement floor and nailed them together.  Okay, you probably see the screw gun sitting there and are thinking I didn’t really nail them.  I screwed the first one, but the rest were nailed.  It was faster.

One of six frames

One of six frames

Some time later, the six frames were built and ready to go.

Yep, count 'em ... six frames

Yep, six frames alright

A few days later I got the frames screwed to the base and braced.

Starting to look like a house

Starting to look like a house

I messed up in calculating the roof rafters and somehow missed the correct length by 7/16 of an inch.  As a result, the sidewall studs are not exactly parallel to each other.  Can you tell which way they are off?  Leaning in at the top or out at the top?

Tilted sidewalls or is it just the camera?

Tilted sidewalls or is it just the camera?

With a little help, I got the 6 mil greenhouse film placed on the frames and fastened it down.  It’s supposed to be good for about four years.  See the channels at the bottom with the wire-spring things inside?  Well, probably you don’t in this picture, but click on the picture for a big version and you will.  I had heard that the wire-spring stuff was called wiggle wire, and when I tried to put it in, I found out why.  You have to wiggle the wire, first up, then down, then up, then down as you work each  bent section into the channel.  It went pretty fast, once I was on to it.  Maybe I would skip it next time though, to save some money.

I like it!

I like it!

The white material on top of the rafters is some kind of packing material that I had lying around.  I thought it might protect the plastic from abrasion against the two by fours, and it was a lot cheaper than the felt tape in the greenhouse supply catalog.  I suspect it is going to mildew eventually.  Sigh, I wish I would have done a less ugly job of cutting and installing it.

In order to hold the plastic around the door frame and the frame against the house, I used two strips of wood, each 3/4″ by 3/4″.  One was nailed to the frame and the second was screwed right next to it with plastic trapped between them and under the second one.  I just pulled the plastic tightly across the first strip and pushed the second strip into place and screwed it.

Here’s a closeup of it.

Over the left strip and under the right one.

Over the left strip and under the right one.

To seal against the house, I cut pieces of foam.  It’s called sill seal and I think I paid five bucks for a roll at Home Depot.

Not pretty, but I think it will work.

Not pretty, but I think it will work.

I covered the shelves with galvanized metal lath that you can buy at any building center.



I made the door from 1 x 3 stock, fastening the pieces together with pocket screws.  The top panel has acrylic plastic, but I cheaped out on the bottom with a piece of styrene fluorescent light cover.  Bad idea.  It cracks really easily when holes are drilled in it.  If it fails, I’ll spring for acrylic, which will no doubt happen in the dead of February.

And now it’s done.

Hey, it's a greenhouse!


It’s a bit on the homely side, but should do the job, I hope.  The materials cost about $280, which seems like a lot, now that I think about it.    Really, though, I suppose it’s pretty cheap for a fifty square foot greenhouse.

I will be putting a bunch of black water-filled plastic five gallon buckets inside to act as a heat absorber and radiator to see how that works, solar energy-wise  Unfortunately, I have only white buckets and black paint probably won’t stick to the polyethylene very well.  Still, I will try.

Update January 9, 2010********************

The greenhouse has been doing well for two years, but I really need more room for plants.  I decided to bump out both sides, leaving the base the same size.  As it turned out, the rock wall on one side kept me from expanding in that direction, so I settled for a one-sided bump out.  I hope the greenhouse doesn’t tip over when I fill up that side with plants.

All I did construction-wise is to extend the rafters with 2 x 4s and run more 2 x 4s under the plant shelf to meet the extended rafters.  I didn’t think to take any pictures of the process, but here are a couple of photos to show how it ended up.  It now looks like a backward 4.

I think the homely factor has been bumped up too.

More room!

I’ve now doubled my space, though I’ll be able to keep only short plants on the far side of the new shelf.