The Kratky hydroponic lettuce experiments are moving along just fine! On the right side of the photo we can see the earliest batch is progressing as planned. Note the beautifully white root system developing in the nutrient rich water, along with the air gap that is forming as the liquid evaporates or is consumed by the young lettuce plant.

You can see the rest of the lettuce plants started from seed at the same time as the plant where we show the root system, and compare the leaf growth relative to the younger lettuce plants started from seed on 1/13/19. The different in growth over those extra couple of weeks is notable.

What if we could just start a half dozen lettuce plants from seed every couple of weeks and have an endless supply of low-work, low-maintenance lettuce for personal consumption? I think we can!

Can I really have a steady supply of fresh lettuce with minimal work and very minimal maintenance? I hope so! What’s the idea? Kratky!! This is a form of hydroponics that doesn’t require water movement or an air-stone. This is reputed to be a “set it and forget it” system. What did I do to get this set up?

First, I planted some lettuce seeds into rockwool. Seeds are super cheap, probably less than a penny per seed at the most. And the rockwool is reasonably priced, too, and can get shipped right to your home with Amazon pretty easily. Soak the rockwool until it is saturated, drop a seed or two into the hole in the rockwool, keep it wet with easy bottom watering and wait until you have a nice looking seedling.

Next we mix up the nutrient mixture. I just mixed up one gallon of nutrient solution which is made with one gallon of water (lettuce is pretty forgiving, but ideally we want the pH of the water to be below 7), 1 gram of Epsom Salts, 2 grams of 4-18-28 fertilizer, and 2 grams of 15.5-0-0 Calcium Nitrate. Yes I felt very odd measuring out grams of white powder on a food scale, but this is how we do it.

Next I set a net-cup into a mason jar, or I like to repurpose my glass peanut butter jars (don’t eat the peanut butter that has all that sugar in it that comes in plastic containers … peanut butter should have two ingredients, peanuts and salt). Pour the nutrient solution so it fills the container to a level that is just 1/4″-1/2″ above the bottom of the net-cup. Then we take a section of the rockwool that has the seedling in it and hold it in the net-cup while filling in the cup with hydroponic clay pebbles like you see below.

Lastly, we wrap the jar in tinfoil or a paper sleeve to keep the light out of the water. We don’t want algae growing in there using up the oxygen for the lettuce. We set those jars under a grow light and wait the 4-6 weeks to get a full lettuce plant. Sure, we may want to peek in on the kratky set-up to see how the roots are developing and such, but all-in-all this is supposed to be a hands off grow method.