Withholding watering during rest periods caused no problems due to the compost becoming dry as can happen with rockwool. The vast majority of plants have shown very impressive growth and flowering, with more new leads and better flower spikes. Detail of the Method. This prevents algae growing on top of the perlite, looks much pleasanter, and adds some stability. In the UK the product Silverperl, coarse grade, fits this specification.
Pots have their bottom drainage holes blocked off.
A soldering iron or heated skewer does a good job on plastic pots, but clay pots would need a suitable drill. I expect that custom designed pots may be available in some places. The distance of this ring of holes from the base is varied according to pot size. The purpose of this change of drainage scheme is to provide a reservoir of water at the base of the pot, moisture rising by capillary action into all the perlite until the reservoir becomes empty. This process results in a constantly moist compost whilst at the same time ensuring that there is also constant air space between the granules of compost that are above the water level in the reservoir.