As a rule, no more than 2/3 of the plant should be harvested. Enough should be left to let the plant grow back.
The desired dyestuff (usually flowers, leaves, bark) is boiled with lots of water in a pot; enough to cover at least a few inches above the dyestuff. Each material requires a different boiling method and unless the dyestuff is edible, the pan used for dyeing should never be used for cooking. The ingredients can be boiled a few more times until it no longer yields colour.
- For flowers, they are boiled for 20 minutes and the water is strained to make the dyebath. However, some flowers are heat sensitive; which means that their entire molecular structure can be destroyed by heat. This makes them impossible to produce any dye. Therefore they just need to be soaked in water for 24 or 48 hours for the dye to come out. The timing is dependent on the temperature of the environment.
- Barks, roots and woodchips require overnight soaking. Then they are boiled for half an hour to an hour and the liquid is saved. This is the extract.
- For bugs such as cochineal, they are dried and ground into a fine powder. Then, boil them for twenty minutes. If used whole, they follow the same method for barks, roots and woodchips.