Growing Asparagus

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
• Water thoroughly
• 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