I’ve continued the experiments with the windowfarm and there are actually things growing in there now, though the strategy has been modified somewhat from what I started with.
Most hydroponics systems rely on some kind of circulation to keep the nutrient solution moving past the plants: flood and drain, nutrient film technique, etc. Those are active hydroponics systems. There is, however, also the option of passive hydroponics: hydroculture.
Originally, I was aiming for an active system with the nutrient solution flowing through the window planters in an almost-continuous stream. However, I found that the plants didn’t seem to be getting quite enough water, probably because my circulation was too intermittent and the water level too low. This got me to wondering if the same strategy I was using for the garlic-in-hydroton-and-water would work with my lettuce and tomato seedlings.
And that called for an experiment.
I took one of the tomato seedlings (started in a cube of rockwool) and put it in a jar filled with hydroton pellets. The rockwool cube got nestled into the pellets, then more pellets packed up and around the cube to hold it upright and steady the plant. Then I topped up the jar with fertilizer water (hydroponics nutrients mixed into waste water from the fish tank, plus a splash of vinegar to bring the pH down a little) and set it in the window.
That’s working quite well! The plant is very happy and growing steadily, the stems are nice and strong and the leaves are a good colour. The hydroton and rockwool ensure that the roots are sufficiently aerated, and the glass makes it easy for me to see the level of the nutrient solution and keep it topped up appropriately.
Given this success, I decided to modify the window planters to work in a similar fashion: I twisted the drain tubes up and clipped them in place so that the troughs are now able to hold water rather than instantly drain it out, and filled the whole thing with hydroton pellets with rockwool cubes of seedlings and the odd garlic plant nestled into the clay marbles. With nutrient solution filling the trough about halfway up, the plants are able to get water and air both without any difficulty, and they are in full light as the window mounted planters are right up next to the glass.
Hydroton does not wick water very well, so it’s important that the nutrient solution be in easy reach of the plants roots or the rockwool cube if the roots haven’t grown out of it yet. The seedlings get started in a turkey roaster with a plastic dome lid that sits on top of my natural gas stove, where the heat of the pilot lights warms the tray to about the perfect temperature for early seedling growth. Once the seedlings pop their heads up out of the rockwool, I transfer them to another tray closer to the window so they can have light but still be protected under a plastic greenhouse dome, and when they seem to be well on their way and are maybe starting to seem a little leggy, I move them into the hydroton troughs in the window, nestling the cubes down deep so that the plants can reach the water level.
Everything is growing quite slowly, but as I am not using grow lights of any kind I think that is probably to be expected. It’s early in the year yet, and though we are getting more and more light, the days are still short in this part of the world. I’m okay with slow growth as long as it is steady. I’ve lost quite a few plants to the experimentation stage – some got dried out before I noticed, some seemed to do well for awhile then gave up when they didn’t have enough nutrients … but that too was expected, as I have never grown things this way before.
As it gets a little closer to outdoor-gardening-season, I’ll be starting some seedlings the more traditional way: I was gifted with a large stash of nursery pots that I can use to start plants for outside, and will be putting those into use in a little while. In the meantime, though, I’m really liking the easy setup and care of hydroton planters and liquid plant food.
Stay tuned for more updates as things continue to grow. :)