We've had a huge crop of marigolds this summer. As is true with many flowers - the more you pick them, the more they produce. It takes about 24 hours in the oven at it's lowest setting to dry out the flowers so they can be weighed and stored in a plastic bag. In a good week I can pick and dry three or four buckets of flowers.
Marigolds are a wonderful natural dye that give a yellow that ranges from slightly green through brilliant yellow to very gold. Be sure to use a mordant as the beautiful yellow color requires it. Alum works really well for a bright yellow, copper gives it a green tinge and chrome pushes the color towards orange. Tin always gives a very bright color.
I don't have the dried marigolds up on the website but they will be there in the next day or so.