How to make a greenhouse with a budget!

Well, this I have just got to share with you internetting people!

This idea was originally my Dad's, and it's simply brilliant.

I really have aspired for years to the tomato and pepper growing standard of my Mum's... But I have never managed to grow those wonderfully flavoursome sweet bombs. First it was the howling gales and driving rains of a Scottish hillside that prevented my ambitions, then just lack of proper knowledge on growing temperatures and so forth. This year I decided to go for it with all guns blazing! Last summer my aunt provided me with some really good practical advice on the importance of temperature and light on different tomato seedling stages. And then Dad had this brilliant idea, when we were discussing the expensiveness of buying a greenhouse and us thinking of building a polytunnel ourselves...

We wanted to have shelter for our car for the winter, since our garage is not wide enough for our car - and besides is full of gardening stuff and tools and all sorts... So, Dad suggested that we'd buy one of these tarpaulin garages and put that up. Lots of them about in Finland and cheap as well! And then when we were thinking about the building of a polytunnel, dad suggested that for summer we could change the tarpaulin into greenhouse plastic!

Wow, we thought that was fab idea! So, we went ahead and bought the garage, took it along to Sweden with us and put it up last autumn for winter. Worked really nicely for the car for winter, managed only to bend one of the metallic bars of the front... And then when the snow melted, we took the tarpaulin away and changed it into plastic! I cannot be happier with the result! We got a really nice and spacious greenhouse for one tenth of the price of a 'normal' one.

Here you are: some photos and comments of the process.

 

The garage with tarpaulin on still. We had put an extra tarpaulin on the roof part to give extra support and it did work like a dream. The front doorflap had two very weak normal zippers which broke pretty soon... I'm going to replace them with some sturdier stuff for next winter.

 

 

 

Well, the first thing after taking off the tarpaulin was to 'hot-tape' all the parts that may come in touch with the greenhouse plastic. With hot-tape I mean tape that is very spongy and will cushion any hard surfaces. You should be able to get this from the same place as you got your plastic from. I cushioned all the metal tubes and fixings that I thought might touch the plastic.

 

 

Here you see the overall frame of the original garage. We had already attached the bottom rails into heavy duty treated wood when we made the garage last autumn, so we did not have to anchor the greenhouse in any way. You see my husband there fixing the doorframe.  

 

 

The doorframe was fixed onto the frame with metal strips. It actually hang there pretty snugly and easily. Later on I hot-taped the metal bits of the frame.

 

 

And the bottom of the doorframe was attached into the treated timber that we had used to anchor the whole structure with. You can see the clever use of a horseshoe as a straight-line-weight...

 

 

Here we have already pulled the greenhouse plastic over the structure and attached it in the bottom frame with some wood strips. And the door was made from old bookshelf sides... Just attached them together with two bits of similar width wood pieces.

Notice the red clips! We put two of them per corner with some padding in between. Actually they are very important in keeping the plastic from ripping away from the bottom when it's breezy. I took one off for a couple days to use it elsewhere, but put it quickly back after I noticed that without it, one bottom side started to rip away. The clips add stability to the whole structure.

 

 

Here you have a front view. I had ordered the plastic in such a size that we could just pull it from one long side of the frame to the other and then gather the ends and attach them at the front and back frames.

 

 

Here is a view of the top of the doorway frame. You can see how I have taped anything that comes into contact with the plastic.

 

 

Here is the finished article!

We gathered the plastic first at the front and tacked it lightly on the doorframe, folding it at the spot where the roof starts. Then we screwed strips of wood on top. 

We left a double fold of plastic on the side of the door so that it will isolate a bit more. The door does not go all the way on the ground as you may see from the picture. We folded plastic double there as well, here you see that it can then also be used as a small hatch that can be opened for some ventilation in cooler weather.  

 

 

Tadaa! And this is the way I've planted my tomatoes, peppers, aubergines, cucumbers and chillipeppers. In big tubs. I think they are 70 and 90 litre tubs. Two plants per tub, plus some basil plants with the tomatoes!

I did not have photos separately of how we made the back part, but here you should be able to see it as well. The plastic was wedged between two planks in the bottom and then we hang one vertical plank from the top and attached in the bottom plank. The plastic was gathered there and folded as you see. Another plank on top to fasten the plastic and we were done!

Later on I had to tape the fold shut from inside, since it gathered some amount of butterflies and other insects... I used the greenhouse repair tape.

 

 

And here is my greenhouse view just last week! The tomatoes are extremely happy as are other plants. I have lots of cucumber flowering and this week my first tomatoflowers opened up as well!

I have high hopes for nice crop. Fingers crossed!

 

And maybe some words on what soil did I put in them tubs.

I started by drilling six holes on the long sides of the tub. Then I poured in a layer of wood chop for drainage; that's a lot lighter alternative to stones or such. Then a nice and thick layer of strawmuck. A thin layer of sand went on that and then I added on a mix of topsoil, bought compost and sand.

The plants seem to really like their soil so far.

I have occationally fed them with tomato fertiliser, but am hesitant of using it as often as they say, since I do have that strawmuck there as well. And the plants look brilliant, stocky, good leaves and with lots of flowerbuds.

 

I heartily recommend anyone to try this alternative for a greenhouse. The only thing we are thinking of changing next year is to add another doorframe or hatch-frame to the back of the greenhouse so that we have proper ventilation. Now keeping the door wide open is not always enough to keep the temperature below 30C.

So, next autumn we are going to take the plastic and door frame away and fit the tarpaulin back again. And we will see in a year, how well we are able to fit the plastic back again! We did leave quite some extra plastic around the edges, so it should work. Wish us luck!