if i remember correctly, the "bulb" turns brown, then you do. i let mine go this year. too hot!! hope that helps. did ya google it? i know sue should be here or remy soon! :') ~Medo
i just know it needs to change colors to dry out.

At the top of the screen click 'other exchanges' then scroll down to 'seed saving' (11th item down on the left side)
There you will be asking folks who are much more familiar with it. Good luck!