Let Us Lettuce

I love lettuce, especially rocket, but I hate buying the bags. As soon as you open them, you release all of the nitrogen from inside, this is what is keeping them fresh. Wilting kicks in shortly after this and I always end up throwing out half the bag (and I can’t recycle the plastic bag!). The best solution is to grow your own lettuce and I have been readying about the Kratky Method a bit.

It's Time for a Hydroponics Experiment using the Kratky Method!

Here’s the plan: try out the Kratky hydroponic method using re-purposed or recycled materials to see if I can get some decent results. If you’ve never heard of the Kratky method (named after B.A. Kratky), it is a passive growing method. This means that no pumps or electricity is needed. A young seedling is placed onto a “raft” that sits fixed atop a tank filled with water and nutrient solution which sits stagnant. As the roots grow down and absorb the water the plant will also grow “air roots” in the space that is left as illustrated below.
The Kratky Method System

How I Set Up My Kratky Method Hydroponic Experiment

I Got Some Clean Yoghurt Pots

One of the initial goals of this experiment is to use materials that I have at hand. I’m re-purposing the yogurt pots I saved from my grocery shopping in Lidl. They are sturdy and hold a good amount of water with plenty of room for roots to grow down. The most important thing is that they won’t let light in. When using this method, you must ensure no light can get at the water otherwise algae will begin to grow on the roots and kill your plant.  First thing I did was to give them a good clean in warm soapy water.



Adding Water and Food

I filled the pots with a mix of water and to the point where the water just touches the base of the plant pot and teabag. Therefore, this will keep the teabags moist until the seeds germinate and start growing roots.

Clean Yoghurt Pots

I Cut Out a Hole in the Lids

A sharpie is ideal to draw around the pot. I tried to cut with a scissors but the craft knife worked better. Cut the hole roughly smaller than the circle so the pot will sit in but not fall through.

Kratky Method Using Re-Purposed Yoghurt Pots

I used a Teabag as a Substrate

To create the substrate I got some used tea bags from the compost bin and cut the top off. I spooned the contents from one into the other essentially filling in tea bag with the contents of two. I don’t know if this will work well as a grow substrate. In professional hydroponic setups people use . Teabag paper is obviously very porous and will allow roots to grow through them. I added some stones from the garden around the teabags to support them because i figured the plant will become heavier as it grows.

I Added the Seeds

I am sewing and because I had these seeds from a trip to the UK.


That Didn't Work - Kratky Method Fail

A week later and there were some signs of life but not they type of life I wanted. Two out of the three pots germinated but along with the seedlings there was mold growing on the spent tea. Of course, how silly of me not to expect this. Tea is not compost, it had not decomposed! So it started rotting away with ideal conditions for the growth of mold. The seedlings died shortly after.

I made two more experiments,  this time with just simple compost as a substrate in the pots but these also failed. Not so sure mold was to blame here so I may try again with just the compost.

Germinating Seeds
Two More Kar

What if I Used Cotton?

What if you just bought some rockwool you idiot!?  Well I might, but not yet, I want to exhaust the “materials I have to hand” before I add to my carbon footprint by ordering more shit on amazon. So cotton. Let’s try this again, this time I am using seeds from IKEA.

Kratky Method with Cotton
Kratky Method Lettuce Seeds IKEA
Kratky Method Chard
Kratky Method DIY

Moisture + Light = Algae

One of the three rhubarb chard seeds I sewed germinated. The cotton was becoming discoloured and it looked like algae might be growing so again I turned to the garden for some stones. Hopefully this will help

Kratky Method Lettuce Seeds IKEA

A few weeks later... hmm... bigger problems

As a substrate the cotton seems to have worked ok. But now I realise that there is a bigger problem. The pot. It’s not blocking out enough light and as a result algae is growing in the water. This might explain the very inhibited grow that the seedling got to. It was positioned on a sunny windowsill so it had plenty of light and the water level seemed ok. Despite this the growth was slow and stunted. I am now looking aorund for better water container options that will fully block the light. 

Problems with the Kratky method
Problems with the Kratky method
Problems with the Kratky method
Problems with the Kratky method
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Give it a try...

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