Harvesting Asparagus takes some patience as it starts out slowly and should be picked in limited amounts until the plants are mature. This means that, if you are planting seeds of asparagus, the full harvest will be mature in three years. One Year Old roots can be harvested after two years of growth and Two Year Old roots can be harvested after one year of growth.
During the first harvest season harvest for two weeks, the second harvest season, three weeks and, when the plants are mature after three seasons, the spears can be harvested for four to six weeks.
Harvest spears that are about the thickness of a wooden pencil and about 6 to 8 inches long, cutting just above the soil line.
To produce white asparagus, as the spears start to grow, mound soil over them, gently, to cover 8 inches or so. As the tops of the spears break the surface, remove the soil and harvest the spears just above the original soil level. The soil keeps the spears from using the sun to manufacture chlorophyll, which turns the spears green. Do not try to harvest white asparagus spears until the root stock is at least 4 years old.