Echinacea purpurea grows easily here in the Northeast and is common in everyone's garden's. It also makes great winter cold medicine. Because of climate change the frosts have been coming later and later in the fall but whenever it will happen, it is best to wait until after one or two hard frosts to dig your roots. The frost concentrates the polysaccharides in the roots making them more powerful medicine. You don't need many to make enough extract for yourself, your family and friends and herlp to keep everyone healthy all winter.
When the frost has happened
Dig and wash the roots cutting off right at the crown. The crown is a very vital place in any plant food or medicinal,and I feel that it holds a lot of the most potent energy of the plant right there at the juncture of the root and the aerial parts (kind of like the navel of the plant).
You can simply chop the roots fine and cover with vodka or brandy or half and half 100% alcohol and distilled water, in a jar and put it in a cabinet for 6 weeks (I like to cover a full moon cycle as that time will guarantee that whichever moon phase you make it in it will benefit from the pull).
I also like to run the roots and the menstruum (the alcohol and water or vodka portion) through a blender.
You can also measure your roots by weight and then add twice the amount in ounces of the menstruum to be more exacting then just chopping and filling a jar. if you do this then just double your weight in ounces with the fluid ounces of your menstruum.
It is also nice to make an extract from the leaves and flowers earlier on in the summer, and also from some seeds after the seed heads (the cones of the cone flower) have turned dark but before the birds have eaten them all. Then you can mix some of each finished extract all together making the root extract the largest part and you will have good strong medicine.
Don't let the process be daunting. It really isn't hard, it is fun to do and it saves money.
My name is Bonnie Bloom and I am a clinical herbalist. Plants give us clothing, shelter, food and medicine. They are an intrinsic part of our earth ecology, diverse and essential. They breathe our carbon dioxide and generously give us oxygen. Where would we be without them.