I have been using a mix of Growstones and milled sphagnum moss. Depending on the orchid genera, the mix may be from 40%-60% Growstones. This mixture, using the pour through method of testing pH, does run a bit on the alkaline side but my fertilizer solution contains 5 mL per gallon of lemon juice and this nicely moderates the pH issue, in addition to potentially supplying citrate to the plants that may be beneficial.
I have used this mix for at least 2 years and my mixed collection (Paph, Phrag, Miltoniopsis, Cattleya, and Phalaenopsis) has grown and bloomed well (under LED lighting).
Growing in straight Growstones may be more challenging and I wanted a mix that was more moisture retentive. Mixed with the milled sphagnum moss, I think the Growstones are giving increased aeration and also probably some Calcium.
Sent from my iPad using Tapatalk HD
|