How to Grow AsparagusDOWNLOAD FILE
May 18, 2016
Asparagus (Asparagus officianalis)
- Family: Liliaceae
- Hardiness: Hardy
- Ease of growing: Difficult
- Nutrient needs: Moderate
- Water needs: Low
- Common propagation: Crowns (one-year-old nursery grown)
- Weeks to grow transplant: 10 to 12
- Start: February
- Plant out: May
- Typical spacing: 12” to 18” in 4’ to 5’ rows
- Depth: 10” to 14” trench
- Plants per square foot: 0.25
- Time to first harvest: 2 to 3 years
In Michigan, the most commonly grown varieties are Millenium and Jersey varieties (e.g. Jersey Giant; Jersey Knight). Millenium is a newer variety from Canada that is well adapted to Michigan’s climate. It does well on heavier soils, but is somewhat more susceptible to foliar diseases than the Jersey varieties.
Preparation and planting
Asparagus is a perennial crop that can be expected to produce for 10 years or more, so it is particularly important to take the time to find a suitable site, and prepare it carefully. Sandy, well-drained soils with pH between 6.8 and 7.5 are preferred. Relatively high levels of phosphorous should be provided (up to 200 lbs P/A) and incorporated before planting. Perennial weeds, such as quackgrass, should be eliminated before planting. Plant asparagus crowns in a trench 10 to 14 inches deep. After planting, cover the crowns with 2 inches of soil.
As new shoots grow, fill in the soil around them, but don’t cover the tips of the shoots. Do not harvest the first year after planting and only harvest sparingly in the second year. Add N and K sources (about 50 lbs N/A) after harvest in subsequent years. Asparagus has relatively low water requirements, and generally doesn’t need irrigation in Michigan on most garden soils. However, on very sandy soils, irrigation is helpful during fern growth.
Insects: Asparagus beetle, Asparagus miner.
Diseases: Rust, Fusarium, Phytophthora, purple spot.
Harvesting and storage
You will get the first large harvest in the third and fourth years. The season begins in May and can continue through June. A 25-foot row should yield 7 to 12 pounds of asparagus. Snap off 8- to 10-inch spears that are less than 1 inch in diameter before the buds open. Leave those that are smaller than a pencil. Complete the harvest before July 1. The ferns that grow following harvest should not be cut until they are completely dead in the fall or just before growth begins in spring. Store asparagus under cool and moist conditions, such as the crisper of your refrigerator.
Developed by James Manning, Undergraduate Research Assistant, and Daniel Brainard, Vegetable Extension Specialist; MSU Department of Horticulture; Gary Heilig, MSU Extension educator.