Passive hydroponics refers to growing in pots full of a medium such as perlite or greenmix or to hand watering rockwool slabs. Normally, for this type of cultivation, it is recommended that the grower make up a large container of nutrient at a time. A 200 litre plastic drum is an ideal container. Once this is made up to the correct strength (conductivity), the pH can be checked and adjusted to the ideal level of 6.
A careful note should be made of the exact amount of pH Up or Down that is added at this time. A good pH can be used for this because although the pH measurement takes longer than with a meter, it only needs doing occasionally in passive systems. The nutrient solution in the drum should remain quite pH stable and can be applied to the plants as needed.
A careful note should be made of the exact amount of pH Up or Down that is added at this time. A good pH can be used for this because although the pH measurement takes longer than with a meter, it only needs doing occasionally in passive systems. The nutrient solution in the drum should remain quite pH stable and can be applied to the plants as needed.
