I've increased the number of trees I have in containers and now I am getting sick of mixing buckets of water-soluble fertilizer to fertilize them all. Is it possible to use time-release Osmocote as the sole fertilizer, foliar spraying only, or Osmocote plus a foliar spray? Foliar spraying is far easier to do on a large scale than mixing buckets for me because of the tiny amount required. And I can mix osmocote into the potting mix or add it on top later.
I have Jack's Professional 25-5-15 - thanks to whoever posted that coupon code on the CGF. Is this usable as a foliar spray? The instructions don't mention this. It contains 0.12% iron, and I know iron is not recommended for foliar spraying.
I also have Osmocote Plus (with micronutrients) 15-9-12, which doesn't have the right NPK ratio for citrus. I would have to add extra and deal with too much potassium and phosphorous. How big a deal is this? I repot yearly, and when outside all trees get rained on regularly. When i water manually I usually give around a gallon to each tree.