Photo 1 : I figured out a way to expand my windowfarm, building a last bottom row of four containers, sitting independently on the shelf right under the window. Now, I’ve got 22 containers in this window. The tubing system in the upper part is still a mess remaining to be addressed, though. But the slow-drip irrigation in itself is working fine. My 8 litre reservoir usually lasts 6 to 10 days without needing to be refilled. It feeds 2 columns. My smaller 600mL bottles feed one column each. They last 24 to over 48 hours.
Each morning, I open the 8L reservoir flow valve to release one drop every two or three seconds. Then, the change of pressure in the big reservoir automatically slows the dripping flow to a stop after a few hours (I estimate two to four hours). For my small bottles, though, I open the valves to maximum until every clay pot is dripping abondantly (one minute is enough), then I ajust the flow to 1 drop per 2 or 3 seconds and close the valves 30 to 45 minutes later.
After supper, I make the same operations. I always make sure all valves are shut before going to sleep. My plants don’t seem to suffer from this schedule, but they are still small and it’s winter. The true test will come with summer heat, I guess.
Twice, I experienced leaving all of them without irrigation for 24 hours, and I couln’t see any difference. The 50-50 mixture of clay pellets and rock wool seems to work very well to keep a good moisture level.
Photo 2 : These new containers needed to be irrigated too, so they are positionned right under each existing column, but they also need to drain into a big bottom reservoir, big enough to collect the upper reservoirs’ whole contents.
Photos 3 and 4 : These terracotta pots came with their insides covered in a glazed coating as well as the other pots. But their draining hole is located on the side of the pots. Just perfect for what I had in mind ! First, I cut four lenghts (2,5 in. long) out of a very rigid straw (the kind of stick they use to tie a balloon on). I put some plumber tape ( white and very thin, my husband says it’s teflon) several layers around its middle to make it thicker and I wedged it in place in a screwing motion, through the draining hole. Then, I put aquarium silicone sealant around the straw and the draining hole, inside and out. I experienced leaking problems, so I had to make touch-ups to seal them completely. Finally I connected the straw to a lenght of 1/4″ blue silicone tubing (bought in the aquarium section in my neighborhood’s pet shop).
Photos 5 and 6 : I put the pots on their shelf and directed the tubing down into the plastic bucket sitting under the shelf. (I still need to find a neet way to secure these tubes so they won’t get out of the bucket inaverdently and spill water on the floor.)
Photo 7 : The story of a mistake. My first attempt at collecting water involved these big tubes. I put two of the small blue tubes inside this big one, trying to imitate the draining system on a washing machine. But the blue tubes ran horizontally before plunging vertically into the big transparent tube and the water level inside the terracotta pots would have to build up to about 2 inches high before gathering enough pressure to push its way through the blue tubes. It made a sudden flushing effect and when both containers were flushing at about the same time, the water would flow back up the transparent tube and spill on the floor. Only then did I figure out a most obvious and simple way to make things work. Now, the draining is almost instantaneous. Only a couple spoonfuls of water sit at the bottom of the pot before the water drains.
Photos 8, 9 and 10 : As a next step, I wanted to isolate my plants’ roots from the entrance of the draining tube. I didn’t want to take the chance of clogging it. So, I needed a container inside the pots, and I had to make sure it would not block the water’s evacuation. I used two different methods to make a “platform” in order to raise up the containers a little. First, I cut three slices off a cork and layed them down the bottom of one of the square clay pots. In the other, I cut the bottom part of a strawberry plastic crate and put it upside down in the square pot, making a side notch to give room to the tubing.
Both pots drain well, so if nothing nasty develops on the corks, I’ll replace the plastic crate with cork.
Photo 11 to 14 : For the inside pots, I found these 2,5 in. “earth-friendly, biodegradable pots, made of compressed straw, rice husk and bamboo, taking one year to degrade after exposure to elements. ” 37 cents each at Walmart. I would rather find permanent pots, but I wanted to avoid plastic, so I’m buying myself some time with these ( I figure at least six months). I used a square of geotextile material to line the inside of the pot. It will prevent the roots from reaching the draining tube, hopefully. I then filled the pot with 50% wool rock (including 2 cubes hosting each a sprout) and 50% clay pellets, and finally, I cut the excess geotextile.
Photos 15 and 16 : Four plants in place : one Buttercrunch lettuce and one parsley in the left container. I figure I have plenty of time to eat the lettuce before the parsley is fully grown. One question, though : will the remaining roots of the lettuce develop into a problem for the parsley or affect badly the water’s quality ? In the second pot, same strategy : one lettuce and one nasturtium. I needed to train a mesh from under the pot above, because the distance is too big between both pots and the drops of water were splashing around. It was necessary to do the same elsewhere in my windowfarm because the developping foliage can divert the water outside the pot, sometimes. I discovered that leaving some mesh to lie on the clay pellets distributes the moisture much more evenly on the pellets. But I’m not sure it’s necessary anyway. The only drawback is that with the meshing, the water makes no more dripping sound. Snif.
Photos 17 and 18 : An update on my peas and lettuce growth. The photo of the peas is overexposed, sorry.