I've never seen any evidence of a Ca deficiency in plants grown in the gritty mix in the first year. Ca deficiencies are normally pretty easy to spot because the new growth usually emerges deformed. Unless I repot at the start of the next season, which for me includes rootwork and a soil change, I would usually (always?) scratch in additional gypsum and Micromax early in the spring. This year, I added gypsum to many plants I won't be repotting, but I laid off on the Micromax because I'm using FP fertilizer.

Al

Al, thanks for the reply. Much appreciated.

As fast as my conifers are growing in the gritty mix I'll probably have to move them to larger containers next year so I will be repotting and doing rootwork at that time.

A followup question: When I repot next season I'll probably reuse some of this years' gritty mix for some smaller trees. I'm guessing by that time any gypsum I've added to the soil mix this season will be depleted and there will be no issues with adding additional gypsum to this soil next season, correct?

Thanks again!

Dave

I wouldn't think so, since I've done it regularly and never encountered evidence of a problem attributable to the practice.

Al