Question 1

What is the Kratky method?

Accepted Answer

A passive hydroponic method developed by Dr Bernard A. Kratky at the University of Hawaii. Plants sit in net pots above a reservoir of nutrient solution. There is no pump and no electricity: as the plant drinks, the solution level falls and an air gap forms that supplies oxygen to the upper roots.

Question 2

Should I top up a Kratky reservoir?

Accepted Answer

No. Fill it once and never top it up. Raising the level again submerges the air roots the plant grew into the gap, which can suffocate them (Kratky, 2009).

Question 3

What pH and EC do leafy greens need?

Accepted Answer

For leafy greens, keep pH between 5.5 and 6.5 and EC between 1.0 and 2.5 mS/cm. These bands are for leafy greens, not all crops.