So my prototype window farm is up and running. It has two separate water lines: one straight, three plant column that has transplanted mint of different types on the right, and one three-two staggered chain with red cabbage started in the system from seed. I’m using this prototype chain to do a dry run on the nutrient solution I’ll be using for my later systems. Mint is a relatively hardy plant that can live in partial shade, plus it makes great tea. ^_^ The red cabbage is to make a pH indicator, and to see how leafy plants do.
The system is set up off of one 2watt 3.2L/min air pump that cost me about $8 US, with a one gal (~4L) reservoir for each line. The only thing right now that bothers me is that I can only run one water line at a time. The path of least resistance seems to dictate that only one line will have air bubbling through it, and the other will stay stagnant when they’re both hooked up to the same pressure source. I’m sure this can be fixed with something small and simple, I just can’t seem to think of anything yet besides using a separate pressure source. =/ Check valves are expensive too! I only need one, other than that I’ve gotten away with CHEAP t-valves (One for each water/air mix, one for a bleed line on each, plus one for the air hose split) and on-off valves (One for each air line and bleed line). They cost less than 50 cents a piece.
The top left line is the lift, the line to the right of it is coming from the reservoir, leading into the coil, and ends at the mix point in the bottom t. The valve at the bottom is air pressure, and the valve resting in the coil is the bleed line to correct flow problems and take water samples.
The line itself can be a bit more expensive depending on what type you get. Vinyl is the cheapest, but I use clear 1/4 in (~6.5 mm) f-pvc line even though it may grow algae because I can spot clogs and see the color of the liquid as it goes from plant to plant. The coil is to stop it from bubbling back into the reservoir. It’s 10 ft long and wrapped around the lift line for organization; that gives time to see the backflow and correct the system, and also provides a sizable resistance to direct the lift. I think the biggest thing if you’re going to use a coil for your resistance is to make sure it’s longer than the lift line is. Imagine if you lay the tubing out on the ground, it would make a big “Y” or “T” with the air pressure coming from the bottom. If there’s water in both lines and one end is longer than the other, which one is the air going to go to? This seems to all be about least resistance.
I ran water through the system for a few days before putting anything in it to clear the system out and make sure it worked, and then again for two days after the plants had been started to hydrate them and see how long it took to run a gallon through. The reservoirs are not connected directly to the drain either. I have a separate “waste” containers for each line that I pour periodically back into their respective reservoir. This way I can dose the actual volume of liquid I’m putting through the system rather than having to base it on time. I can also see how much the plants absorb this way, and check nutrient differences.
The nutrients I’m trying out consist of a liquid dirt I’ve called “compost tea.” It’s made by bubbling air in a filter containing preferably de-chlorinated water, a couple big scoops of dirt from my worm farm, a few cups of a concentrate made from boiling seaweed water down to a dark liquid (though the boiling may have killed the reason I added the kelp in the first place), and then something sweet (un-sulfured molasses or honey) to promote growth, but in principle I think you could adapt this process for brewing all kinds of “liquid dirt.”
I’ve gone this route because I can make it from my kitchen scraps without spending a dime, and I’ve heard and read ridiculous praise about it everywhere I turn. My particular setup for the “tea” used a 5 gal (~20L) bucket, the same kind of air pump I use for the window farm with a bubble stone, and a filter sack for paint. Cost me ~$20 US for the setup, and although the worm farm may take a bit of work, you could probably just use well fertilized dirt and be fine. The filter is used to take out the solids after the mix gets frothy.
This seems to be able to make enough for a whole bucket of really saturated stuff off of one week’s worth of kitchen scraps and worm digestion. I dilute this down a bit, and try to bubble air through it every few days to keep things alive. I’ve forgotten recently, and I’m worried what I’ve done =/ Keep it covered as well or else it’ll grow algea from the light.
Now this does involve having a running worm farm, and that has turned into a bit of an adventure. I have a large corner just outside the kitchen for my composting setup, but let me tell you what, I have loads of healthy dirt thanks to it. =)
I’ve been planting things in the used dirt mixed with some vermiculite and pearlite, and it seems to make things grow pretty well. The sun in Houston is really hard to fight though, so I have some indoors and some outdoors to see what can tolerate the different conditions.
I think I need to pay more attention to the nutrients in the dirt I use for the tea, but so far so good, and no sticking, or any signs of clogging at all. I do have some transplant shock going on though. The mint on the top is citrus, the second in line is the sweet mint, and the last one is a chocolate mint.
The citrus mint has had the worst of it. One of it’s runners won’t stay in the soil, so I’m losing over half of it. There are some parts of it that are looking hardy again though.
The sweet mint has developed small dark spots around almost all of the leaves, but other than that it looks fine. I have no idea what they are. We’ll see what happens, might snoop around the net a bit.
The chocolate mint on the other hand is healthy as a mule. Going strong with no visible issues so far. I think the upper plants may be acting as filters for it. Maybe that means I need to dilute the solution some more.
They all seem to be turning toward the window now and stiffening up again at least. The cabbage has sprouted and is reaching for the light too.
I water the plants 2-3 times a day, where I cycle half a reservoir or so, which is about half a gallon/2 liters. It takes about an hour to cycle that much water. Once after I wake up, once at midday, and once before I crash at night.
I’ll post a how-to for the whole thing once the next system is up and running. I’m designing a “column-farm” where the plants grow around a central freestanding column. It’s going to be cheap and easy, the column is built out of three 1x4s using hand tools, and the rest is basically a four column streamlined version of this.
Here’s a playlist on some nutrient stuff in the meantime:
More to come =)