Most fertilizers for acid loving plants work well for blueberries, these are often marketed as Azalea fertilizer

Yes that’s true. I’m wondering how to make it.

Hard to imagine making anything for less than just buying a large package of Miracid/Miracle Gro for acid loving plants. I find that in the "normal" section and it's like 10 bucks for a ton of it. Doesn't seem to make sense trying to re-invent the wheel on this one ... not to me anyway. Now making your own batches of custom compost may be worth some time and effort though.

True, I can get a 50 pound sack of commercial 19-9-17 Ammonia based blueberry blend from the local agricultural fertilizer supply for $10. Of course not everyone lives where blueberies are grown as a (minor) commercial crop.

Ya, I only found one store that carries it, it’s $7 for a 1 pound bag.

For $1 more, I can get a 45 pound bag of ammonia sulfate 21–0–0 crystals over in the ‘farmers’ section.

You mentioned “ammonia based”, that may be a starting point for me. I recently found a store that carries most of the commercial fertilizers used locally for rice and vegetables. Very cheap. I have trouble translating the labels, as well as getting a clear description of what they have, but there’s a good chance I could put something together.

I can try to ask at the local fertilizer supply about an ingredients list, they are distant relatives by marriage, though it will be a couple of weeks as I am heading out of town Tuesday morning on a 2 week trip.

Cheers Ike, that would be helpful. Don’t go to too much trouble. Whenevers convenient for you.

I have a small bag of the ammonium sulfate 21-0-0 and 2 big blueberries in 15g pots. How much should I be adding per gallon of water to fertilize? Kinda scared of burning them.

I use one level scoop of 21-0-0 per watering can, which is around a 1.5-2.0 gallon can ( using a recycled green miracle grow scooper that is 1.5 Tbsp) ... translation, a tablespoon per gallon ... never burned anything. Since in pots, and especially if dry soil or they haven't seen fert in a while ... suggest .5 Tbsp per gallon of water and observe. To be even safer, you could water the blueberries, get the roots wet, and like a half hour later, swing back through with the fertilizer at .5 tbsp per gallon ... same concept as eating before you go to the bar ... buffer. Maybe you could go even stronger than 1 tbsp per gallon eventually ... but the general rule is fertilize light and often. Also late afternoon once the sun has clearly started it descent up until dusk is the best time ... has all night to get adjusted and take it up before the sun hits it full force ... just keep it off the foliage if its getting late and it won't have time to dry ... wet leaves all night "bad".