Green Roof DIY Plant Starter Greenhouse - On the Cheap

Green roofs are harsh mini-eco-climates and may not always be the best place to germinate seeds.

So if you have a seed source for a particular plant you want to use on your green roof - or elsewhere in your permaculture gardens - a seed starting greenhouse or hothouse may be helpful.

Greenhouse for Green Roof Plants - Cheapo but Works!

Yet in today's economy many of us do not have the extra dollars or euros to spend on a hothouse or greenhouse.

The photos here and sketch are of a very nice greenhouse we recently built out of scraps.  Our total out-of-pocket cost was about US $20!

The greenhouse is 12' wide by 18' long by 8' tall - 3.7M wide x 4.5M long  x 2.4M tall (approximate dimensions).

Green Roof Plant Seedlings

Surprisingly, this week as the temperatures outside dropped to around 20F  -6.7C  ice formed on the inner portion of the pastic however the jugs of water we had sitting in the greenhouse did not freeze.

All the seedlings were cold but fine - not frozen.

The greenhouse's performance pointed to two important facts - 1. you can build a great little greenhouse out of scrap and, 2. by adding jugs of water to the inside of the greenhouse you can keep the hothouse warm enough to protect plants.

Water Jugs Store Heat - Keeps Greenhouse Warm

Water has a high specific heat value and stores heat absorbed during the day from sunshine, releasing the heat back into the greenhouse at night when the temperatures are cooler.

To build the hothouse, first find 6 lengths of scrap pipe.  We used metal fence posts we had found in a scrap pile where someone was remodeling a house.  Take a big hammer - we used a sledge hammer and drive the pipe into the ground spacing them about eight or nine feet apart (2.5M).  Make 2 parallel rows of these installed pipes - see the sketch.

DIY Hothouse by Kevin

To the pipes we added flexible 1/2" electrical conduit we had left over from a construction job.  This conduit is very inexpensive to buy at the hardware store - about US$1.50 each - you need 7 total.

Attach one side with a ZipTie (WireTie) of the conduit to a pipe in the ground and then easily bend the other side over to the opposing pipe.  Proceed to attach, bend and attach all the conduit to the pipes to make the hoops.

We then covered the hoops with a piece of left over greenhouse plastic and attached the plastic to the hoops and pipes with Big Office Paper Clips - they work great.

Presto - the greenhouse was built!  Green Roof Seedlings are now growing!

Good luck with yours and as always - Happy Green Roofing....Kevin