Should I let my asparagus grow into seed while it is still growing or should I harvest till they no longer grow. I have heard both ways.
Asparagus does not go to seed every year. Your harvest should end when the next spears come out scraggly and thin. There is no correlation between the two (harvest & seed). I'm not sure how you could stop bloom and seed set.
I pick until the spears are the size of a pencil and then I let it go. The plant needs to gather energy for next years crop. Picking until it 'stops growing' would indeed kill the plant.
Asparagus that sets seed (little balls that eventually turn red) are female plants, and less productive than the male (opposite of homo sapiens) . Some folks remove the females. The age of your asparagus planting also determines how much you harvest. The first year, no harvest; second year, light harvest; and after that, you can harvest until the spears become small, as Coppice said. A light fertilizing after the last harvest helps the asparagus roots strengthen for next year's crop.
I suggest grubbing out the female plants (the ones with seeds). It will cut down on fence-row volunteers that can harbor beetles or other problems, and then spread them back to your cultivated patch.
