I wanna share with you the so called “Kratky method”, a hydroponic way of growing herbs, leafy greens and all sorts of stuff without any growing media.
I use glass bottles, which I made a nice 3D-printed adapter for. It fits an optional wick (useful for the start) and holds everything in place. You can even refill them later on!
Plant roots need both oxygen and water. If you only put them into a full glass of water, they’ll die due to suffocation (“overwatering”/ root rot).
In the Kratky method, the level of the nutrient solution drops as the plant grows, and oxygen is provided that way.
I really like this method for growing lettuce on my balcony.
The main benefit, compared to a classic growing medium like coco coir (or even soil), is that you don’t even need any growing media you have to dispose of later on. Zero waste.
And of course all those neat other hydro benefits, like fast growth, less pests, and so on.
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I’ve used my 3d printer more for hydroponics than anything else. It’s great for making baskets/adapters to hold sprouts in whatever container you want. I settled on 2" PVC with ebb-and-flow irrigation, but Kratky fascinates me.
Do you have trouble with algae in the glass containers?
Kratky fascinates me
I love the Kratky method especially for easily disposable fast growing short lived stuff like lettuce (1-2 month grow cycle).
Other methods like your ebb and flow is better for high value crops like chilis and weed imo :)
Do you have trouble with algae in the glass containers?
With clear glass, which I used in the beginning, definitely yes.
With green/ amber ones nope, or at least only veeery weakly.Currently I try spray coating a few ones with white pigment, and see how it turns out with heating up in the sun and algae compared to the uncoated brown ones.
I’ve done a fair bit of kratky and dwc. Typically you avoid algae and other root rot issues with opaque containers.
I guess you are using colored glass mainly to reduce algae growth?
Correct! 👍 I haven’t observed much algae growth yet.
But I’m also experimenting atm how it turns out when I spray coat them.
This year I have a 50% shade cloth, but last year they were uncovered and hot afternoon sun fully blasted onto them, cooking everything to mush.
I now painted a few of them white, and I hope this reduces algae growth and heating significantly.
Good old white-wash with slaked lime should do the trick as well I would say.
I never heard of that and looked into it. I haven’t found anything regarding glass. Are you sure it adheres well to a bottle? Is it weather proof?
It should, yes. It is commonly used on old glashouses with glas pannels around here.
Oooo the 3D print is so clever!! I’ve been thinking of growing some green onions in water but was trying to figure out how to suspend the plant so that only the roots grow down… I suspect the 3D printer may hold answers for me
Really cool! What’s the wick made out of?
Polyester
You can order plant wicks like this. Very cheap. I find that they are more useful for watering potted plants in soil, but they’ve got all kinds of uses.
Kratky is a very approachable way to start with hydroponics, but with the lack of aeration, I’d just start with something like deep water aquaculture to begin with because it’s not much more complicated. It takes up more space but works better for plant health (especially with longer-lived plants) and is easier to measure and manage nutrients.
Sure, but for short lived, disposable stuff like leafy greens or herbs it’s perfect! There’s basically zero cost, and it’s totally passive. You also don’t need to wash/ waste any growing medium.
But for other more high value stuff, like weed or chillis, I use other, more sophisticated methods.
