Recently I experimented with making dyes by boiling fruits and vegetables to create natural dyes from from things I had around the house. Things like blueberries, turmeric and onions.
Natural dyes do produce beautiful gentle colours but they don't stay on the fabric unless they are fixed with a mordant, which are mostly chemicals that I don't have at hand.
I started by boiling the washed white fabric in a salt water mix to prepare the fabric to take the dye.
In another pan I let the crushed blue berries, onion skin and lemon pieces boil in water to release their natural colours.
The fruits produced lovely lilac shades
After taking out the plain fabric from the salt water I added the dye to the pan of water and added the
t-shirts , you can see the lovely lilac colours it created.
Natural dyeing is great fun and the results always have that element of surprise as you never know exactly how it's going to turn out, there are usually small flecks and patches where the fabric may have been folded, creased etc, but that adds to the beauty of it
The Natural History Museum natural dyes page is a great introduction to natural dyeing fabric which the kids will enjoy doing with you.