Article 2-6 Calcium Peroxide

Where can I find Calcium Peroxide and can you tell me more about it. – Lloyd

Calcium peroxide is available in most indoor garden supply retail outlets. Consult your yellow pages or retailers index in the back of Maximum Yield. It goes under the trade name of “Oxy-Cal” and “Soil Blaster,” to name a couple. As an amendment to your potting soil, the recommended rate according to Oxy-Cal is: 9 grams/1 tbsp/15ml per 1 gallon of soil/4 liters. If you would like to mix larger quantities (usually in a toy swimming pool or on a sheet of plastic) mix in 4tbs (60ml) per cubic foot, so approximately 16-20 tbs (240-300ml) per bale of Sunshine or Pro-Mix. Always wear a mask or respirator, gloves, and goggles (especially the mask or respirator) as directed. There isn’t much information out there on Calcium peroxide being used in recirculating hydroponic systems. I would think that small amounts in rockwool cubes and slabs might be O.K. Rockwool tends to be slightly higher in pH than required. This can be desirable when adding high quantities of phosphorous during later stages of flowering. These are often fertilizers that reduce pH. Further pH adjustment is also used in the form of “pH down” to maintain a level of pH5.5 in the reservoir, pH in the slab should be slightly higher.

Anyway, the Calcium peroxygen might raise the pH in the slab further, requiring some fine tuning of the pH in the reservoir and monitoring of the slab pH. Be careful that the Calcium peroxygen doesn’t clog drip lines resulting in starved plants. As far as chemical reactions go, concentrated calcium and concentrated phosphorous should not be mixed. The calcium would turn into useless sludge. Nutrient solutions are generally diluted enough at required plant levels. Erik at Max Yield