and even then you need to stop cutting when the stems get thinner than your finger, so think stems on new plants are probably OK.

Plants will send up thin sprouts first year, these will grow into fern like plants, let them just be and in fall they will die back
and repeat following year.
If you can leave them alone and let the ferns just grown, by year 3 you can pick anything bigger than a pencil thick, but you should leave a few un picked to keep the plants healthy.
Be sure to read up on fertilizing.
Happy growing!

If you grow from seeds, the first year they will be little whisps,
smaller around than a tooth pick.

Every year, they get a little larger.
The 3rd year, some will be thicker than a pencil,
and you can take some of those.


This is a photo of one of our older beds in the Spring,
and has examples of all different sizes.
In harvesting, you take the big fatties, and leave the others for next year.
In the above photo, we should have cut a couple the taller ones the previous day.

We have some Martha Washington that we planted from 2 year old crowns,
and were able to harvest a few this year.
Very tasty.

http://www.democraticunderground.com/11593181

as the years go by. Don't cut for a few years (some books say 7) Never cut one thinner than a #2 pencil. Don't take more than a third of the stalks and allow the stalks to flower and have little berries. Cut to the ground after all the fronds have died back. Fertilize and mulch for the winter. Pull back the mulch in early spring and watch the new stalks push through the ground.