This product is used to supplement calcium in my 1-Part Flowering Formula when your soil-like grow media is not already buffered with some kind of calcium, such as dolomite or gypsum. Coco fiber is the most commonly used media that fits this description.
Note: The Rockwool 2-part Flowering Formula (also good for DWC) contains calcium, so Calcinite is not required in this case.
Calcium is barely used at all by cannabis plants past day 30 of flowering. If you are using Jen’s Craft Nutrients Veg Formula according to instructions, the veg formula will be used for the first 3 weeks of flower in unbuffered media. When you switch to the 1-Part Flowering Formula on Day 21-22, this is when the Calcinite is needed, for the next 8-10 days. Then you can drop it out for the remainder of the flowering cycle.
Because the application rate is low and the period of use per cycle is brief, a quart size of Calcinite is a match for a gallon set of veg or flowering nutrients. In other words, it’ll last a while!