Building a shade house from poly-pipe

I grow many of my vegetable using hydroponics, and have done so for more than 25 years. However, the summer heat is too much for tomatoes and many other vegetables, so I usually drape 50% white shade cloth over them This is not very satisfactory, so at the end of 2012 I set about constructing a shade-house. What I wanted was a simple and cheap structure that would enable shade cloth to be hung over the vegetables, but allow it to be removed in winter. Searching the web gave some ideas, and with a bit of experimentation I arrived at a structure, which is functional but not yet completed.
The hydroponics is laid out in a rectangle about 7.5 metres by 1.5 metres, which consists of a number of long containers – troughs, and large diameter pipes cut in half or 90mm storm-water pipe filled with perlite.

I purchased 50 metres of 50 mm agricultural green “poly pipe”, which comes in large 100 m rolls. The irrigation shop was very happy to cut 50 metres of his large roll. This cost $183. I did try 25 mm poly pipe but it was not strong enough to maintain the shape I wanted – rounded hoops about 3 metres high.

To keep the poly pipe hoops in the ground I used 1800 mm fence “star” iron- droppers which cost $6.14 each. Don’t get these from your local garden shop, they will charge almost double; I went to a steel outlet that sold farm and fencing steel. They sold the droppers in packs of 10.











I made seven hoops from pieces of poly pipe each with a length of 7100 mm. The base for each is 2200 mm wide, so the height turned out to be approximately 2900 mm which was adequate to pass over the top of the tomatoes. This is easy to work out.If the base is 2200 mm wide, the circle part of hoop will have a height of 1100 mm (i.e. the radius) and the total length will be pi x 1100 mm (remembering it’s only a half circle). Hence we have:

Length of top    3450 mm (pi x 1100 mm)
Sides            (7100 – 3450) ÷ 2 = 1825 mm
Total length    of pipe 7100 mm
Total height    1100 + 1825 = 2925 mm

 

I placed the iron-droppers 1300 mm apart along each side of the area and 2200 mm from each other, across the structure, forming a nice rectangle. One could use closer gaps or ones that were wider, although I don’t think that gaps greater than 1500 – 2000 mm would be useful.

The iron-droppers were hammered in about 400 mm which was easy since the soil is mainly clay with few rocks – although it is very hard in summer. To bend the poly-pipe without kinking it I laid it out in the sun over lunch. This made it very easy to bend into a nice curve – which was slid over the iron-droppers. (As a teenager, I grew up on a farm and my father’s pet hate was kinked poly-pipe, as it often split, and certainly produced a narrowing that slowed the water flow. This taught me how to handle poly-pipe, which can have a mind of its own!).

Since the pipe fitted very nicely over the iron-droppers, it was easy to adjust the height as the area sloped away on the northern end. I simply slid the pipe a little way up the iron droppers, and with a self-tapping screw held it in place.

To tie the poly-pipes together one could use a range of materials. I chose 25mm polyvinyl chloride (PVC) water pipe which I painted green. These were held onto the poly-pipe with 25mm saddles, screwed in with 10g x 25mm self-tappers.






I intend to tie the hoops together with five lengths of PVC pipe. I thought I might need internal braces, but with the 50% shade cloth under 75 km winds (we get severe winds in summer here), the structure has not moved an inch.

The shade-house is still not completely finished. I had a piece of 50% white shade cloth, which I had from seasons, which I just draped over the plants, but it is not long enough. This means one end of the shade-house is covered well with white cloth and about 2m with a heterogeneous collection of green. Sometime in the future I will purchase sufficient to cover the remainder.

The (nearly) finished structure