To preserve the integrity of the garment and promote the longevity of the dyes, hand wash in cold water with an eco friendly soap that is ph neutral and dye/fragrance free. After washing, hang or lay flat to dry out of direct sunlight. Iron as needed on low heat.
Keep in mind that natural dyes are "living" color and ph sensitive, which makes them susceptible to color changes when in contact with substances of a different ph level such as sweat, lemon juice, white wine, and baking soda. In the case of spills, any reaction can be counteracted with immediate washing in cold water with a ph neutral soap.
Store your plant dyed wares in a cool dark area and out of direct sunlight. With a little love, your naturally dyed piece can last for many years of regular wear.