Kratky Method Lettuce [ Growth Report ] Day 14

Kratky Method Lettuce is an easy way to grow vegetables in an apartment. The Kratky system uses passive hydroponics and needs no pumps or airstones. It needs no power to run so you can use it anywhere.

Kratky Method Lettuce is an easy way to grow vegetables in an apartment. The Kratky system uses passive hydroponics and needs no pumps or airstones. It needs no power to run so you can use it anywhere.

The traditional Kratky method for lettuce uses a floating raft. You only fill it once at the start. My system is a bit different but uses the same basic principles but also some improvements. At least I hope they are!

The Kratky system is best for small plants because it is only filled once. Large plants would need a garbage can sized reservoir which really is not practical for an apartment so I added some modifications to mine to allow me to grow larger longer maturity plants in it.

To learn how to build a Kratky system check out my article Hydroponic Wick System – Kratky On Steroids (indoorvegetablegrower.com)

Kratky Method Lettuce Day 7
Kratky Method Lettuce Day 7 Video

I am currently using a LED light with a lot of blue in it. The blue spectrum promotes short stocky seedlings but I will be modifying it to include more white light. This is a 150W aquarium light. The colors are adjustable and the light has a built in timer. I really like using it for seedlings. You could probably use it for a 2×2 grow space maybe even a bit more. 


I plan on switching it out for a larger light in a week or two. My Kratky tote will be sharing this space with 2 DWC buckets in the near future.

How do you start Kratky lettuce?

I started the Kratky lettuce from seed placed in jiffy pellets but you can use coco, rockwool, or rapid rooters. I was planning on growing in coco and putting it inside liners and setting these in my net pots.

But the liners I received were not the same size as the 3 inch inserts I originally had. They were too big so I decided not to use them. I did not want loose coco to fall in the tote.

I set pre soaked and expanded jiffy pellets in the net pots and filled in around them with growstones. You can use perlite or hydroton instead. I planted a few seeds in each pellet. I have 6 buttercrunch and 6 mixed leaf lettuce.

Kratky Method Lettuce Add Ons

The Kratky method is designed to work as a passive hydroponic system. It does not need pumps, airstones, or wicks but that does not mean you can’t add them.

I was concerned the pellets might dry out over time so I added a wick to each net pot. I made them from strips of polyester batting. I also added airstones. 

How do you grow Kratky lettuce?

Normally the Kratky system starts with water slightly above the bottom of the net pots. As the water level drops the roots grow into the water. The roots above the water line become air roots and the ones in the water become feeder roots.

But once they grow in the air they cant go underwater. So you cant refill a Kratky and if you cover the air roots with water they will rot and die.

In a regular Kratky system lettuce works well because it is a fast growing plant. But larger plants like tomatoes or peppers would run out of water before they ever could mature.

Why I Am Adding Airstones In My Kratky 

By adding airstones you can keep your Kratky at the same water level and at the same height for the entire grow.

So my plan is to let the water drop a few inches and then maintain it at that level. The oxygenation makes this possible. It also means you can grow larger plants in a Kratky.

Here is an article about growing with the Kratky method. His method is the more traditional raft system but it is still informative.  https://university.upstartfarmers.com/blog/kratky-method

Kratky Method Lettuce Day 14

Here is an update on my Kratky lettuce and some other hydroponic vegetable projects. I think the Kratky lettuce will need to be thinned out but I am waiting for the plants to get bigger so I can make a salad from the thinnings.

Also really looking forward to seeing what my DWC buckets can do. I have an Early Girl bush tomato in one and a Bush Belle Hybrid pepper. I also have a bush cucumber I really want to grow but no room for it right now.

Kratky Method Lettuce Update

Plants were thinned out to one per pot. Growth has been good. Around day 30 for this Kratky tote.

Growing Hydroponic Lettuce Indoors

Learn about using a grow tent for vegetables