As part of our decision to have more shade in our garden we have found that using black poly pipe used for irrigation attached to steel star pickets can provide a sturdy frame for shade cloth (a knitted poly fabric product available in various sun filtering intensities) to be attached to.
We had been researching this building method for some time but finally decided to just go and buy 20 metres of 50mm poly pipe at the rural supply store in town. It cost $2.75 (AUD) per metre and thankfully was delivered to our place as it was quite difficult to coil it to a small enough size to fit in our van. So there we had it 20 metres and 10, 165cm star pickets to experiment with.
One area I felt needed shade was the Tank Beds in the Dog Pen Garden. These cut down old rainwater tanks that were too leaky to hold water are an excellent size for filling with soil and compost and growing salad greens and vegies at close proximity to our back door. This is in our zone one. The main problem was that they heated up too much in summer so shade of some description was needed. The perfect spot to try the poly shade structure.
The area measured 2.5 metres by 2 metres and I already had some spare lengths of shade cloth that would fit. We measured 2, 4 metre lengths and these were cut with a hacksaw and fitted easily over the star pickets after they have been firmly hammered into the ground.
The poly pipe doesn't have to go all the way to the ground as it fits quite firmly and there is no way it would ever blow off even in the strongest of winds. If necessary they could be bolted on or attached with wire.
Using 4 metre lengths of poly pipe over a span of 2.5 metres gave a height of 2.2 metres. This would vary with the height of the star pickets and length of poly pipe.
The shade cloth was attached using wire but a better way to attach it is to sew the ends of the shade cloth into a hem on a sewing machine using polyester thread and a triple (stretch) stitch and thread the poly pipe through this hem.
The other end of the shade cloth was trimmed to size standing on a ladder!
I have only used a single length of shade cloth at 180 cm wide here but if I required more shade I could replace this with 360 cm wide cloth or sew 2 lengths together.
The growth of salad greens in this area has improved greatly and I can now face the summer onslaught of heat knowing the plants will survive and I will be using a lot less water.