The key to good asparagus production is good fertilizer. Apply nitrogen at least twice a year - once in the spring when growth begins and again at the end of harvest season.
Water frequently during the first two years supplying 1" to 2" per week. Mulch heavily around the plant to conserve soil moisture and reduce weed growth.
After the fourth year, reduce irrigation to every two to three weeks, watering so that the moisture penetrates the soil at least four feet deep.
Plant Development and Care
At planting, place 2 inches of soil over roots and replace more soil as the plant grows. Do not cover tips of spears with soil. Maintain healthy fern growth during the first 2 years to ensure long asparagus production for future years. Asparagus should not be harvested the first year.
Asparagus does not compete well with weeds. Keep weeds and grasses away from plants and mulch with 2 to 3 inches of compost each year. Also, avoid tilling the soil around asparagus, as tilling disturbs the delicate root system.
Formerly it was grown almost entirely with the soil ridged up high over the roots at harvest time so that the shoots would develop in the dark and be white, as harvested. Now, however, we have learned to prefer green shoots which develop in the light, so that ridging is no longer so common.
White asparagus spears are considered a delicacy. To blanch spears, mound soil 8" high over asparagus in early spring before spears emerge. When the tips of the spears emerge through the top of the 8" mound, push a long-handled knife into the base of the hill and spears well below the surface. Pull cut shoots out by the tips and level the mounds after the harvest season.
Germination Time (Days)
53 days at 50° F 24 days at 59° F 15 days at 68° F 10 days at 77° F 12 days at 86° F 20 days at 95° F 28 days at 104° F