Have you been feeding it regularly and keeping it well watered as necessary?

Dave

Yes!

I get asparagus but no new plants - I am deciding if I need to buy more to fill in open areas or if asparagus will eventually fill them in - and if so how long will it take?

A bit of a misunderstanding perhaps but asparagus doesn't really generate "new plants" in the usual sense of that word. Although if some female plants develop berries you may get some sprouting from them.

Asparagus crowns expand, grow bigger, and so put put more shoots and roots. Each crown has a massive root system. For example I have a few 15 year old crowns that are close to dinner plate size in diameter. So the roots of that crown could easily be 3x that size in diameter.

Assuming proper fertilization and watering each crown will approx. double in size each year. How long it will take to fill in all depends on how far apart you planted them. If you used the usual 12" spacing then again, assuming adequate supplemental feeding etc. the roots of each crown will have filled in that area within approx. 3-4 years. Gus isn't a quick turn around crop like most garden vegetables. It is a long term investment.

But that doesn't mean you can over-crowd it either. Do that and you get skinny spears and dying crowns.

Dave

Great got it thanks! For sure my better bed (2 years old now) is really expanding, I did not know they did but without a doubt there are a lot more stalks and spreading.

Thanks!