Name: Carol
Message: Hi! My daughter and I are planning to dye 40 5.6 oz white cotton t-shirts.  We are tie-dying them one color using RIT.  How many boxes should we purchase? I searched the web (and a box of RIT) for answers but could not find anything other than 1 box is enough for 1 lb dry weight or 3 yards medium weight fabric.  I thank you very much for your assistance.

Oh, dear. Please do not use all-purpose dye! You can buy much more satisfactory dye for a lot less money.

The way to figure out how much dye you need to use is by weighing your shirts. Get on a bathroom scale holding all forty of the shirts, and then without them, and subtract your weight from the total. Your total shirt weight might be twenty pounds, in which case you would need to use twenty boxes of Rit. At $2.79 per box, this will cost you $55! (For a dark shade, you should use two to four times as much dye, so you will need to increase the cost estimate if you want a dark shade. The Rit dye usage estimate assumes that you want a pale to medium shade.) The bad part is that all-purpose dye is a pain to use because it requires you to simmer the shirts in the dye for best results (washing machine temperatures are too low to work well with this dye), and, even then, the dye will fade quickly, and bleed forever in the laundry, unless you use a special dye fixative called Retayne, which you would probably have to buy by mail-order.

Instead, I strongly advise that you buy an easier-to-use, longer lasting, brighter, less expensive dye called Procion MX dye. For a single color, the easiest method is to follow the instructions in one of the links found on my "How to Dye in the Washing Machine" page. You can dye up to eight pounds of shirts at a time in most top-loading washing machines. Be sure to add exactly the same amount of dye, salt, soda ash, and t-shirts to each load so that the final dye color will match. Divide your twenty pounds of shirts into three loads of the same size.

How dark is the color you wish to dye? Just as for Rit dye, you will need to use more dye for a dark shade, less for a pastel shade. To dye twenty pounds of cotton t-shirts to a medium shade, you will need about eight ounces of Procion MX dye. An eight-ounce jar of Procion MX dye costs about twelve to fifteen dollars, plus shipping, but it varies by dye color. (If you use this link to order your Procion MX dye through Amazon, my site will receive a commission at no additional cost to you, or you can order it from most of the retailers listed on my Sources for Dye Supplies Around the World page.) You will also need a couple of pounds of soda ash (here's the link to buy soda ash through Amazon), and several pounds of non-iodized salt. If you decide to soak the shirts in soda ash and the squirt the dye on, as is usual for multi-colored tie-dye, you will not need salt. (See "How to Tie Dye".)

If you use a fiber reactive dye, such as Procion MX dye, instead of all-purpose dye, your work will be easier, your results will look much better, and the dye will last many times longer without fading on other clothes in the laundry. I will never again use all-purpose dye dye on cotton, because the results are so bad. I get a lot of sad emails from people who have used all-purpose dye and then want me to tell them how to make it work better.

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