Organic cotton and Lyocell can be washed, but don´t have to be washed that often.
I recommend alternatives like hanging it in your bathroom while showering, airing it at an open window or hanging it next to your heating in the winter.
When you do wash your knits make sure you set the washing machine on a short, low temperature wool or hand-wash cycle. Turn the garments inside out to prevent peeling and wash your knits in a protective laundry bag if possible. (You can wash Organic Cotton and Lyocell up to 60 degrees but to protect the fibre and reduce the energy consumption I do not recommend that.)
Lay down the knits on a dry towel and let them dry flat, naturally away from direct sunlight. Our knits rarely need ironing, as the fibre is naturally resistant to wrinkles. Using a steam iron on the wool setting does help the garment to get back in its original shape.