Pinging the list... I am going to relocate my 5 year old Asparagus to a sunny place in my yard and hopefully double the output over the next week or so here in North Carolina.
Dig double deep down, a lot of compost.
Asparagus beds at Monticello have been bearing asparagus since planting in 1780's
but are dug up about every 50 years to enrichen the soil.
Free leaves and compost at Town and Village Road Superintendents garages where they collect the leaves in Fall.
Avoid sewage treatment plants as the sludge generally contains many 'heavy metals', like lead and mercury.