For a dry green colour, you can combine henna powder with rice flour or maida. To get wet colours, mix it with water. Recall that henna combined with water can stain your skin and clothing.
Option: 2
For Holi, you will need the following ingredients to make green colour:
Henna powder
Spinach
Coriander
Cornflour or refined flour
Water
Steps:
To make a dry green colour for Holi, mix henna powder with refined flour.
The result will be a dry green colour that is smooth and natural.
Grind the greens with water and strain them to get a wet green colour.
Combine cornflour with the remaining juice. Till the colour is uniform, thoroughly mix.
Spread it out and allow it to dry in the sun.
Pour it through a fine strainer after it has dried.