April in Wisconsin is the time to start growing Asparagus patches! This long-lived perennial vegetable, once established, will provide 15-20 years of the spring harvest. You can find Asparagus at Heyden’s Gardens in Spring as bare-root crowns. We also carry potted plants later in the season.
Starting with a weed-free, nutrient-rich, loose planting bed will give you a good foundation for many years of harvest.
Select a site in full sun
Work in generous amounts of organic matter
Dig a trench 12” deep and 12” wide
Fill the bottom of the trench with nutrient-rich organic matter
Create a 6” high mound every 18”-24” in the trench
Select male varieties of Asparagus for planting (e.g. Jersey Knight or Jersey Giant) as they produce much higher yields since they don’t have to put energy into producing seeds
Set a single Asparagus crown on top of each mound, spreading the roots around the top of the mound. The crowns should be about 6” below soil level.
Cover each crown with 2” of soil and fill the trench between mounds to the same level
As plants grow, continue to add more rich organic soil until the trench has been filled back up, level with the soil surface
Asparagus likes moisture so keep bed well-watered
Asparagus will not tolerate competition, so it is important to keep the bed weed-free
Mulching the bed with clean straw will retain soil moisture and discourage weed growth
Fertilize each spring with a balanced organic fertilizer
Do not harvest any spears during the first two years. This allows the plant to put all of its energy back into establishing a robust root system
Starting the third year, apply the 2-4-6 week rule. Harvest for two weeks the third year after planting, four weeks the fourth year, and six weeks every year after that
Spears should be harvested when they are about the width of a pencil and around 6” high. To harvest spears, cut them off just above the soil level. Continue harvesting until plants produce only skinny spears, less than a half-inch in diameter
Once you stop harvesting the spears will grow into tall feathery plumes of foliage, reaching 4’-5’ in height. Leave this top growth in place through the growing season and through the winter, cutting the dead stems down to the ground level in spring to start the cycle again