Having a potassium issue in my garden (indoors) . Please me please

A customer has a question and I hope we can get some opinions on it, thanks

Ok do im having a potassium issue in my garden (indoors) im in 1 gallon pots perlite and coco , the first thing i read on youre site was about wood ash is good for this i was thinling of using some out of our fire pit outside is this a good idea , and how much and how pften should i use this , i was thinking of a tsp in 1 gallon of water and just using it on one plant first please tell me youre thoughts on this thanx and have s good day

Using wood ash will work just fine, be sure to check the ph after mixing. Wood ash is very alkaline. Ph to 6.0-6.5 for soil. Happy growing.