Many of my blueberry plants are blooming. I've gotten the impression that this isn't the right time to fertilize them, but I'd like to hear some opinions about this. Also what kind of fertilizers are being used?
I usually don't fertilize a lot during bloom. But in pots about once a month with 21-0-0 is baseline for me. But I've also used water soluable or slow release complete fertilizer. Any of them work.
If I need rapid growth then I fertilize once a week.
fruitnut, I'd guess the 21-0-0 you use is ammonium sulfate. Could you tell me how much you mix up (tsp per gallon) for your monthly feeding...I have a 20 lb bag of it and I figured that 225ppm is 0.84 tsp of 21-0-0 per gallon water. But I'm not sure what strength to use with blueberries.
I think what I've used is about your rate, one tablespoon per 2.5-3 gallons water. So that's one teaspoon per gallon more or less.
You can find plenty of discussion by searching. One is below.
Here is a link that might be useful: 21-0-0 on blueberry
You just have to be careful of it especially on dry soil and in pots. The ground is a bit more forgiving.