I usually start looking in the 3rd week of April for signs of it..but nothing this year.
Funny thing about asparagus..turn your back on the bed for a day or two, and sure as heck the next time you look it will be sprouting like crazy. Harvesting it every day for the last week now.
Asparagus loves nitrogen..If you have access to it, dump some chicken manure on the bed in the early fall,, and let it rot down over winter. I don't dig it in as that could disturb the roots.
Another way of improving production from year to year, is to allow some of the spears from each root, to go to fern. I usually allow the skinniest spears do this. The ferns draws nutrition down into the root, and keeps it healthy.
You can also harvest the seeds from the ferns, for starting seedlings in the spring. Once the seed pod is dark orange, and squishy soft, (usually mid fall), squeeze the black seeds out of it. Stick them in seed trays in early spring, and transplant to the garden when they become small ferns. Takes a few years for new plants to produce good crops, so be patient!