How far apart to plant asparagus
Set asparagus crowns 12 to 18 inches apart in the row, with rows 4 to 5 feet apart. Clemson Extension uses 15 to 18 inches in trenches 4 to 5 feet apart, and University of Maine Extension uses 1 foot in rows 5 feet apart. Plant the crowns 6 to 8 inches deep in a trench, per Clemson.
The calculator opens at 15 inches, the middle of that range, laid out the same distance each way in a bed.
How many asparagus crowns fit a bed or row
| Space | Crowns at 15 in |
|---|---|
| 4 × 4 ft bed | 9 |
| 4 × 8 ft bed | 18 |
| 3 × 6 ft bed | 8 |
| 4 × 12 ft bed | 27 |
| 25 ft row | 20 |
| 50 ft row | 40 |
| 100 ft row | 80 |
The counts keep half a spacing clear at the bed edges and row ends, the way the calculator counts. In a 4 ft wide bed at 15 inches that gives three rows of crowns. At Maine's 12 inches, a 25 ft row takes 25 crowns.
Planting crowns in a trench
Asparagus is not planted at its final depth in one go. Clemson digs trenches 12 to 18 inches wide and 6 to 8 inches deep, sets the crowns in the bottom, and covers them with only 2 inches of soil. As the spears grow, pull in about 2 more inches of soil every two to three weeks until the trench is full. University of Maine goes shallower in heavy clay or silt, with furrows only 4 inches deep, and keeps 6 to 8 inches for sandy soil.
Clemson plants from March 1 to April 15 in the South Carolina Piedmont and February 1 to March 15 on the Coastal Plain.
Male hybrids and a long-lived bed
Asparagus stays in one place for many years, so the spacing you choose now is permanent. Clemson expects a bed to stay highly productive for seven to eight years before it slowly declines, while University of Maine says a well-planted bed can produce for 15 to 20 years. Maine recommends all-male hybrids such as Jersey Supreme, Jersey Knight and Jersey Giant, which it describes as longer-lived, more vigorous and more disease tolerant; Clemson says the new all-male cultivars outyield the old ones about 3 to 1.
When you can start cutting
Be patient with a new bed. Clemson waits until the third year for a light harvest of 3 to 4 weeks. University of Maine allows 2 weeks of cutting in the first harvest year, 3 in the second and 4 in the third, and stops cutting by June 15.
To work out how many crowns your household needs, see asparagus plants per person. To plan the bed with other vegetables, use the raised bed planner, and fill it with the raised bed soil calculator.