We planted two year crowns last year and let them grow with zero harvest.

Asparagus is doing very well this year, but I know this is the first year for harvest.

How much can I harvest? When should I stop harvesting?

1st year I'd pick very sparingly and stop picking early. Next year you're golden

Yup, light harvest. If the spears get to pencil size stop.

2X to the above. Years ago I cheated and paid the price!

Put rock salt around the plants, they like salty conditions. My son did that and now the second year he has more than he can handle.
He started with some roots from my mother's plants.

By rock salt do you mean magnesium sulphate? Epsom salt? Just curious.

I think my fil uses table, or stock salt. NaCL

That sounds so weird. I will go look up salt and asparagus.

That's impossible to have too much. Always a friend who wants some.

Articles I have read state salt around the plant was an old practice used to prevent annual weeds. It has no benefit to the asparagus other than eliminating annual weed competition.

Interesting. I have heard of people using epsom salts or sul-po-mag to correct deficiencies but usually in very small amounts. Never heard of using salt as an herbicide. Asparagus must be pretty sodium tolerant.

Correct,use 10-10-10 they are heavy feeders.

That sounds right cause salt kills just about everything. I accidently spilled some solar salt from my water softener on the ground. Nothing grew there for years.

Had a patch in the woods and I salted it found a hole there a couple of days later deer loved it!

Yep