Our first meal of asparagus is usually around May 21. I know this, because that was my late husbands birthday and we usually had our first picking then. This year we had a hot spell for two weeks in late April that warmed up the earth and started the asparagus growing in early May. When a heavy frost was forecast on May 15, I gathered all the asparagus that came up including the thin ones I would not usually gather. Even though asparagus overwinters well in zone 3-4, it is not frost hardy and any spear left standing would be shrivelled and inedible in the morning.
Asparagus beds are started in spring. Put the bed in a location that will give them plenty or room as the ferns it produces are about 4 feet high and almost as wide. They also will need support to keep the ferns from breaking off in the wind. I use five foot garden stakes and twine to make a cage like support. Dig a trench about 1 foot deep and about 2 feet wide in a single row. Partially fill the trench with compost. Spread the asparagus roots out over the compost with the stalk or buds up. Cover with garden soil top off with manure and then mulch with straw or leaves. The spears should be able to poke through the mulch.
The bed should not be harvested for 3 years, after that you can harvest sparingly until the first week in July for the next 2 years. The fine ferns that grow are needed to nourish the roots to store the food needed to get through the winter. In the 5th year you can harvest everything that comes up until the first week in July. An asparagus bed should keep producing for another 16 years. Asparagus grows best with lots of manure applied in spring and fall and kept well mulched.
When my children were young, one of the chores they had to do was help us spread cow manure on the garden, we raised beef in those days and had a steady supply. My daughter used to call manure re-newer. I don’t know if she couldn’t say the word or why she called it that. If you think about it, manure is re- newer.
Here is a list of cataloges that sell asparagus plants and seeds. Jung Quality Seeds, Gurney’s Seed and Nursery Co., Miller Nurseries, Johnny’s Selected Seeds, The Cook’s Garden, Henryfield’s Seed & Nursery, Burpee, Seeds of Change, gaurenteed organic, Michigan Bulb Co.,