How To Build A Greenhouse


We show you how to build and a customise flatpack greenhouse and sleeper deck 

We show you how to lay a simple jetty-style sleeper deck & then use this as the base for an awesome kit-form greenhouse.

"I’ve always wanted a greenhouse. One a wee bit bigger than this though.
A greenhouse gives your year round control over your growing conditions and gives you the ideal environment to get seeds and cuttings started.
Now this will give you a great example of the difference that greenhouse growing conditions can make.
I put four Clivia seeds in each of these two pots. One of them I put into greenhouse conditions and one of them I just put into a warm, sheltered spot in the garden.
The difference between growth really speaks for itself. In the greenhouse pot, all four seeds have taken and are well on the way to developing leaves. In the outdoor pot, two seeds have withered and died and the remaining two have only just developed a root.
I’d always written off my dream of having a greenhouse as too expensive, but not anymore. You can now get some seriously awesome kit form greenhouses for under a thousand bucks. I’m going to show you how easy they are to install.
This corner of the yard doesn’t get used for much more than mowing. It catches a good range of sun and is protected from the worst wind, so it’s a perfect spot for a greenhouse.
First off you need a floor. If you have a level area you might just lay a gravel bed. But we have a bit of a slop, so I’m going to make a jetty style floor using sleepers.
The floor is simple to lay, but first it has to be marked out. I’m making mine bigger than the greenhouse footprint, to give me a landing out the front and level space down the side.
The sleepers I’m using for the floor are a new type of treated pine from Ironwood called Sienna. They are arsenic free and so low tox they are certified safe for kids playgrounds.
Now the floor of my greenhouse is going to be 2.4m wide. That just happens to be the length of the sleepers and that saves on cuts and saves on wastage.
I’ll then be laying those sleepers on a series of bearers but because of the length of my floor, I will need to join a couple of sleepers together. This is simply done by joining one full-length sleeper with another cut-down to give you the required length.
Centre a sleeper offcut that is at least 500mm long over the joint, then secure with at least three bugle baton screws on each side of the joint.
I’m using three rows of bearers so I can just clear away and level. If you have a height or fall difference, you can just pick this up by adding a gravel bed or screwing on 500mm long sleeper blocks at about 1.2m intervals underneath.
Once you’ve laid your rows of bearers, check they’re level from end to end and relative to each other.
Then it’s a simple case of putting your sleepers on top and screwing them down with bugle baton screws.
Well I’ve finished my floor a couple of weeks ago, and since then I’ve just let it sit and the reason for that is when you use timber sleepers this way in the landscape, they can move around a little as they dry out. So you want them to settle right down before you put anything on top of it.
Time for the greenhouse. Believe it or not, the 3m by 1.8m greenhouse on assembly comes in only two boxes.
Once you’ve unpacked, read the instructions and check off all your parts first. Then it’s onwards and upwards.
Once you get rolling, you’ll see assembly really is as simple as using a few nuts and bolts with the included pipe spinner to slot everything together.
To give me greater control over airflow and circulation, I’ve added one of these premade louvred window panels. It replaces one of the whole side panels and allows me to open and close it on hot days to get better airflow on hot days through the whole greenhouse.
There will also be a ventilation panel in the roof, which is what I’m moving onto next.
The roof is quick and easy to add just clipping and bolting together, before sliding the poly panels in. These poly panels are super tough and allow maximum light penetration to get the best plant growth.
The hopper window in the roof can be locked open in a range of positions to allow you to regulate airflow and temperature through your greenhouse.
Now I’m sure you would have noticed that in this point in time, there isn’t actually anything holding my greenhouse down to the ground.
That could end really badly on a windy day, so I’m going to fix that quite simply by using bugle baton screws to screw down through the frame into the sleepers.
Well that’s the greenhouse itself finished. Now I’ll just go round and check that all the nuts and bolts are nice and tight and then I’ll add some shelving.
At the front I’m putting in a workbench for potting and storage. Beside this as the same height as the bench surface a couple of light duty shelves for seedlings and light duty pots. And up the back a few heavy-duty shelves for larger pots.  
For the summer months I’ll add a cloth kit, just to cut the sun’s intensity a little bit. These smart little clips hold the shade cloth in place and can also be used to support small hanging baskets or wire for climbing plants.
Fill with plants and it is all that easy."

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