Chuẩn bị hoa để phơi khô. Bọc đế hoa bằng túi giấy. Cắt đế hoa. Treo ngược đế hoa. Kiểm tra đế hoa định kỳ. Sau khi đế hoa khô hoàn toàn, hãy bỏ túi ra.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Sunflowers are ready to be dried once the back of the head begins to turn a deep yellow to yellow-brown.  The sunflower head must be dried before you collect the seeds. Sunflower seeds are easy to remove when dry, but nearly impossible to remove when still moist. Most of the yellow petals should have dropped off by this point, and the head may begin to droop or wilt. The seeds should feel hard when tapped and should also have a black-and-white striped appearance, or perhaps all black, depending