How to Prepare Coco for Seedlings
Buffering with a strong dose of
CalMag prior to using the coco allows you to provide relatively little
CalMag during the seedling stage of the grow. However, buffering solutions themselves have a high EC, and seedlings could be burned if they are placed in coco fresh from the buffering process. Therefore, it is important to reduce the residual EC in the coco before transplanting the seedlings.
When I begin a grow, I prepare and buffer enough coco for the final containers. I keep the bulk of the coco/perlite moist with CalMag Water in fabric pots until I need it. When it comes time to place seedlings into coco, I fill the seedling container with coco/perlite and then flush it by pouring pure water with a pH of 6.5 though the container until the run-off is less than EC 100 (0.1). This flush is important because otherwise the residual high EC from the buffering process could burn your sensitive seedlings.
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