First I cut swatches from my fabric to test them to make sure this is really what I wanted to do and that I was going to get the result that I wished for. I used these containers to dye the swatches. It looked great so then...
I boiled a large stock pot of water and added a ton of tea bags. At first I only added maybe like ten but realized quickly that that wasn't enough. So I ended up doing tonz more. There's no specific recipe, I just used these same measuring cups and containers to check the darkness of the tea, and went from there. The only problem is I was filling a large plastic rubbermaid bin to do this project so I couldn't just go by the color in the stock pot, but rather get it dark enough to make all the water in the bin fairly dark as well. I reccommend only doing one yard of fabric at a time if possible, because it's so much easier and you can just use the tea in the stock pot to do that fabric. The problem for me was I was using a 3 yd peice of fabric for a bench seat cover and couldn't cut the fabric into yards so I had to dye the whole piece. --which is where the arthritis came in! ;-)
Here's my first 3 yds of fabric in the bin. I actually had two 3 yd pieces of this same fabric, so I was busy!
You let your fabric soak up the tea until it's the color you desire. Could be real quick, could be hours. Depends on the darkness of the water and how dark you want it. Keep in mind that it's always going to look darker when it's wet, so if you think it's the right color, it may get lighter once you rinse it. Once the fabric is the right color you wish for, then rinse it under water until the water runs clear. Then I just put mine in the dryer at that point, but I imagine you should wash it and then dry it. I just wanted to "seal" the tea in by drying it straight from there. ??
This is a picture of my swatches at the first. You can see that they are much "dirtier" than the original fabric and that's what I was going for exactly. Unfortunately once the project was done, I had nothing to compare it too so this was the only picture I had that could sort of show the difference in before and after. And below is a picture of my fabric put to work! 