I've used ammonia diluted 1:10 with good results. I have also diluted it more than that and it seems to work too. I feel strongly that 1:1 or 1:2 is far too strong and one will risk damaging plants. Besides, the ammonia will go much farther diluted more and cost a lot less. I've got over 200 hostas and even at 1:10 I go through 5 or 6, 2 litre bottles of ammonia.
