Things You'll Need
Plastic tub or bucket
Soda ash (sodium carbonate)
Any knit fabric that is made from natural fibers can be easily dyed at home. Purchase dye that is appropriate for the particular knit fabric you want to dye, whether it is cotton, wool or silk. Most dyes state which type of fibers they are suitable for on the packaging, along with specific guidelines for use. Some knit fabrics made from synthetic fibers will accept dye; some will not. The equipment you use for dyeing should never be re-used in the kitchen, so find old equipment, or purchase supplies specifically for dyeing. Protect your surfaces and clothes while you work, and wear rubber gloves and a dust mask throughout the dyeing process.
Pre-soak your knit fabric in a solution of warm water and soda ash. Use one cup of soda ash per gallon of water, making enough to saturate and cover your fabric completely. Allow the fabric to soak for at least 30 minutes, then remove it and squeeze out all the excess liquid.
Mix the powder dye with room-temperature water in a plastic bowl following the manufacturer's instructions. Add the powder to the bowl first then add the water slowly while mixing. Make enough dye solution to saturate the fabric.
Place your damp fabric into the bowl with the dye solution and stir it so the dye can evenly penetrate all of the fabric. Cover the bowl with plastic wrap and leave it undisturbed for at least two hours. The longer you leave the fabric, the more intense the color will be--leave it to soak for 24 hours or more for the deepest color.
Move your fabric from the dye solution to the sink or a clean plastic tub. Pour the excess liquid away. Rinse the fabric under cold water, moving the fabric around so that it all gets rinsed. The color of the rinsing water will get lighter as you work. When it is mostly clear, either rinse it in a bucket several more times, or wash the fabric several times in your washing machine.
Wash your fabric one more time in the washing machine or basin. Add laundry detergent. Allow the fabric to dry naturally.
The soda-ash solution can be saved in a sealed container for future use. If your final fabric color is paler than you expected, simply repeat the process and dye the fabric again, this time allowing it to soak in the dye solution for a longer period of time.
Soda ash and powder dyes are toxic and must be handled with care. Wear a dust mask and rubber gloves when you use them and be careful not to spill any.