We had a good day again yesterday at the commercial site and started assembling the growbed stands. It is estimated that each of these growbeds will weigh 1.3 tons once filled with gravel and water so strength is vital as any deviation from parallel will result in water welling up in one side and the other side suffering from drought. A few millimeters out on one side can result in a huge difference over 6 meters.
As mentioned previously, I have decided to bolt the growbeds together with stainless steel bolts and nut to give an effective 1m wide growbed. This is what the two walls bolted together looks like.
The braces (cross members) were bolted into the 2.1m poles with 100mm x 12mm coach screws and I’m sure that if they can hold the weight of a roof, they’ll handle the weight of a filled growbed.
We also gravelled the whole growbed area and it looks very neat as you can see.
The growbeds are 800mm high (at the top) from the slab on which the tanks stand. The water level in these 1.2m tanks is a constant 1m, so the 200mm difference will provide enough gravity feed to get the water into the growbeds. The growbeds being 250mm high, also means that the bottom of the griowbeds is 550mm from the slab. This will also provide enough gravity feed to drain the growbeds back to the sump.
This is what the site looked like at close of business, with one side of the greenhouse almost finished.
We hope to have all of the growbeds mounted by end of day tomorrow, unless of course the rain arrives. Thereafter we have to apply our minds to how to cap the ends.
Enough for now.