Growing basil hydroponically is quite easy to do. In fact, basil grown hydroponically in nutrient solution can grow more quickly than basil grown in soil!
You'll need a small basil cutting that's at least 2 inches in height, with a few small leaves at the top. Try cutting the stem at a 45-degree angle and leaving it in plain water for a week, or until roots start growing.
When the basil cutting starts growing roots, you'll see tiny roots growing out the bottom of the cutting and along the stem like this:
The roots will continue growing in water. You can continue growing the basil cutting in water for as long as you'd like. Just be sure to change the water once in a while. However, the basil plant will not grow much larger if left in only plain water.
You can transfer the rooted cutting to a container of water with hydroponic nutrients if you want to grow it a lot bigger.
The above basil plant is growing using the Kratky method. It consists of a few parts:
- A mason jar
- A net pot
- Lava rocks
- Hydroponic nutrient water
The hydroponic nutrients I used here is MaxiGro 10-5-14 by General Hydroponics. I used about 1 teaspoon of hydroponic powder per gallon of water. I had transferred the basil cutting into the net pot and used lava rocks to stabilize it.
With just a few small roots inside the nutrient solution, this basil plant exploded in size over just a few weeks.
I've since transferred this basil plant into a larger container with a deep water culture system involving an air pump and an air stone. I'll update this page later with more pictures as the plant grows bigger!
Alternatively, if you want to continue growing the basil plant in a mason jar, I'd recommend covering the mason jar to prevent light entering and causing algae to grow. One way to do this is to paint it. Another is to cover it with dark fabric to block out the light.