Name: Jon Davis
Message: I've been reading your web site with great interest; however, there is one question I have that I haven't seen addressed on your web site (I apologize if it is there and I missed it).

My question: After dyeing, what is the best way to dispose of the left over dyeing solution (after removing the fabric)?

I would like to try your Low Water Immersion technique on muslin to create photographic backdrops. Given the large size of the fabric (9' x 12'), I plan to do this outside. When I'm done, can I just dump the leftover dyeing solution water on the ground? Will it have an adverse effect on plants (other than coloring them)? Is there something that can be done to neutralize it before disposing of it?

Fiber reactive dyes themselves probably won't hurt the plants, but the soda ash probably will. In my experience, the dyes lose their color on the ground within just a few days, probably broken down by soil bacteria.

There are two problems with the soda ash: the high pH, and the sodium content. The high pH can be easily neutralized with vinegar or citric acid (use pH paper to test to find out when you've reach a neutral pH of around 7). Small amounts of dye solutions do not need to be neutralized before disposal, as simply washing them down the drain with plenty of extra water will serve to lower the pH adequately, but large amounts should be neutralized first.

However, plants can be quite sensitive to the salt, even after the solutions are neutralized. This is something that you will also notice if you use salt on your sidewalks to melt ice in the winter (urea is a more expensive de-icer, but better for the plants). You can actually use salt water to kill weeds, though it also kills desirable plants, so you don't want this anywhere where you want anything to grow, ever again. It is best to dispose of your neutralized solutions into the sewer or a septic system, so that the salt will be diluted into harmlessness.

A little bit of soda ash will probably do no harm if watered in well, unless you have particularly salt-sensitive plants. I have not noticed grass dying under my mesh dyeing tables outside, though we do move them around quite a bit. A small amount of soda ash, mixed with dye, drips down while I dye.

Another alternative for you might be to dye your backdrop indoors in the bathtub (the dye can easily be scrubbed out of a porcelain enamel tub, though it must be kept off tile as it can stain grout). This would enable you to avoid carrying a large (and heavy!) amount of water to an appropriate drain.