Dyeing your clothes ecologically and by yourself is not actually such a complicated matter.
All you need is a blender, a bucket, the ingredients and a bit of patience. Some of the ingredients we will talk about are about 4,500 years old (and we do not mean you need to buy them from an antiques store, but that they have been mentioned in historical documents for a very long period of time).
For red clothes, you will need to use the root of a plant called Madder, which was discovered in the tomb of Tutankhamen. The dry roots can be purchased from the internet but they need a few days of processing (mixing with water two times and then fermentation).You can also use a plant called Cochineal, Brazilwood or Alkanet.
In order to obtain yellow, the process is somewhat simpler, by using onion skins and rhubarb. Chamomile and green weed also contain yellow dyers.
The plants will have to be cut and put in cold water for one day and boiled for about one hour in a lot of water (remember you will need about nine liters of water to dye only a quarter of kilogram of wool). If the color you obtain is not as strong as you like it, just add more plant and repeat the process.