How much ammonia sulfate can I put in a 20 gallon fabric pot need to bring soil to 6.2-6.8

Welcome to NGA @Raymondver

What have you filled your fabric pot with? I believe it's normally recommended to use some sort of "potting mix" for containers, and a potting mix would already be at a suitable pH.

Last year I bought Kellogg's potting soil and had a lot of plants that were stunted I checked ph in pots and it is up to 8.1 going to try and use what i purchased last year I have 5 20 gallon and 10 gallon fabric pots

I'm not personally familiar with that potting mix and hopefully someone else here will have some actual experience with it. In the meantime, how did you check the pH? I ask that because a lot of the pH testers that are sold are not very accurate. Also, did you use any sort of fertilizer on your plants? (It doesn't appear that this mix contains fertilizer on its own.)

Thanks for the help I used Doctor Earth fertilizer and the ph meter I have did have a good rating i did test it it seems to be accurate I tested vinegar witch is sup ode to have a PH of 2.00 and it did record at 2.2 I tried the sulfur yesterday and will se how one of the containers does over the next couple of days

This article from the Univ. of Wisconsin might be helpful to you:
https://hort.extension.wisc.ed....

Thank for the help

You're welcome; I hope it works out for you!