I ran out of propagation plugs the other day and I wasn’t in the mood to pay $25 for a bag of 100 plugs, either. Besides, I have tried almost every cloning method known to man including air layering and I have determined that A) rock wool makes for the best cloning substrate, and B) it’s all too expensive. What I had laying around was a case of Cultilene® 4x4x4 cubes. In a pinch and feeling stingy, I cut one of the cubes in half side-to-side (see photo), then again top-to-bottom twice so I would have a grid of nine pieces on the bottom and, owing to the drilled portion, eight pieces on top. That’s 17 pieces of rock wool for less than $1 (the cost of a cube when you buy by the case), or about 5 cents each. The closest I could find to this price was a case of 2,430 Cultilene® plugs for $260, or about 10 cents each, but what the hell am I going to do with 2,430 starter plugs?! The spongey brown plugs run as high as $.25 each and they don’t aerate as well so the cuttings take longer to root in them. Saving $.20 per cutting is a pretty sweet deal for people in the industry who are running thousands of plants each month. An outfit cloning 2,000 cuts per month would save $400 by cutting their own plugs from rock wool cubes and abandoning the brown pre-fab plugs. That buys a lot of beer!