Windowfarm 3.0

I’ve made several attempts at growing plants in my window.

Without a pump, the original version didn’t work very well. With small gutter containers, the second version worked fine for starting the seedlings, but then I couldn’t keep up with their water requirements, and they all died from dehydration.

Enter Windowfarm Version 3.0: Kratky Hydroponics.

How does this work? It’s a completely passive, set-it-and-forget-it system. No pump. No bubbler. No electrical stuff at all, totally silent, just sits there in the window and takes care of itself. It’s awesome.

I tried this out last summer with a couple of tomato plants I got at the grocery store garden centre (the day they were closing it down and giving plants away for free, no less). I planted several outside in the raised bed planter stairs, and they did all right … but late in the season when frosts were heading in, I uprooted one that had a lot of green tomatoes on it and stuck it in a Kratky bucket on the window sill … and it kept growing! And the tomatoes ripened! It was amazing and cool.

So what’s this Kratky bucket? It’s a big pail (I am using small ones because I’m just starting plants – a tomato or cucumber needs a very big bucket if it’s to live there all season, but I believe you can grow a lettuce to maturity in about 4 litres of nutrient solution). The bucket needs to be dark, so that algae don’t grow in the nutrient, and the plant sits in a net pot (a plastic plant pot with big holes in the base to let the roots come through) that is suspended in a hole in the lid of the bucket. I use a hole saw to drill a circle in the bucket lid, set the net pot inside the hole, then fill the net pot with some hydroton (expanded clay pellets made for growing plants, they look like cocoa puffs) and nestle the plant in the middle. The plant drinks the nutrient solution, which is right up to the level of the plant’s roots to start out with, and as the nutrient level drops, the plant grows roots to reach down to where the water is … and because there is air in the space between the bottom of the net pot and the surface of the nutrient solution, the plant doesn’t drown and the roots stay oxygenated.  There are a lot of great YouTube videos showing different gardening set ups using this system, if you want to learn more.

Now, because I live where the growing season is very short, I need to get my plants started ahead of time. And, if I can manage it, I’d like to grow some smaller things, like lettuce, over the winter. I don’t have a grow light set up (yet), but I do have a very bright, very sunny south facing window, and I have put my plants up there. So far, they aren’t looking terribly leggy or anything and they seem to be doing quite well!

I start the seedlings in rockwool cubes that I found on sale at the hardware store last year. Once they are well established, I tuck the rockwool cube with the little seedling in it into a net pot of hydroton and put that into a bucket of nutrient solution. I usually keep the bucket down where I can check on it for a few days to make sure the plant is doing well and hasn’t gotten dried out or waterlogged, then I put it up on the window ledge to soak up sunshine and grow. That’s all there is to it.

There you see a couple of cucumber plants and four tomatoes, happily soaking up winter sunshine.

I do realize that these plants won’t be able to live in these buckets all their lives – they are going to be too large, and they’d drink up all the nutrient solution in a hurry. Once the weather perks up, I’ll be transplanting them outside. I may leave some plants in straight up hydroponics buckets (probably smaller plants like lettuce, which will be okay in my smaller buckets), but the larger plants will be going into soil. I’ll be setting up some sub-irrigated planters outside, probably some large raised beds made from scrap wood or pallets, then lined with a waterproof liner, and fitted with a reservoir in the base (flexible weeping tile). More on that adventure when we get there … but you can see an example of what I intend to build here. Growing straight in the ground is a losing battle against quackgrass, so I am changing gears and putting my energy into building some planters that will be lower maintenance and still give me great yields.

I’m hopeful, anyway.

So hopeful that I started new seedlings today … some beans, some lettuce, some peppers.

I love growing things.