Our lettuce has grown enough that it is time to place them into the actual grow bed to grow them hydroponically.
The Kratky Method uses standing water and does not require aeration. The net pots are suspended partially above the water. This allows the plant to develop roots for water and roots for air.
Kratky Grow Bed
To do this, we built a grow bed out of plastic storage containers. You can do this as well, or you can build more customized beds using a wide variety of materials.
You could build wooden frames and use a pond liner to hold in the water. You could also use IBC tanks. Basically, if it can hold water and you can place the plants in a type of lid so t hat it does no float or let light in, you can grow using the same method.
Other method exist for floating the plants, but that is not what we are doing here.
To ensure good growth you will need to use a fertilizer mix. We were provided a sample of Hobby Formula by MHPGardener. This was mixed at a rate of 1 tsp per gallon of water, along with 1/4 tsp of Epsom salt per gallon.
There are a wide variety of fertilizers available. However, having seen the results MHPGardener is getting, we are keen to follow his example.
Watering the Plants
To properly water the plants you must get water to the bottom of the net pot without submerging the entire thing. Remember, you must leave air space for some of the roots.
Do not worry about the water level dropping. Roots will develop that will grow down into the water.
We placed enough water in to our 10-gallon storage tubs to bring the water 1/2 inch up the bottom of the net pot. This will allow the rockwool to draw up moisture to help establish the plant while still allowing space for roots to grow that will collection oxygen from the air.
The great thing about this system – all we have to do now is wait. There is nothing else to do. No weeding. No cultivating. Likely no bugs to speak of. Just wait and eat when it is ready.
It is, perhaps, the “thing” that hydroponics has going for it.
We will come back in about two week and update you on the progress of the plants. By then, they should be well developed and nearly look ready to eat.