Asparagus Harvesting and Weed Control: A Complete Guide

Harvesting Asparagus for Maximum Yield

Harvest asparagus by snapping 7- to 9-inch spears with tight tips. There's no need to cut below the soil with a knife, as this can injure other buds on the crown that will produce new spears. The small stub left after snapping dries up and disintegrates naturally. A new spear emerges not from the same spot, but from another bud on the crown.

As spear tips begin to loosen (called "ferning out"), fiber develops at the base, making spears tough. Diameter doesn't determine toughness. Pick the patch clean during harvest, never allowing spears to fern out, as this attracts asparagus beetles to lay eggs.

Harvest Timeline

• Year after planting: Harvest several times over a three-week period. Research shows no need to wait two years; early harvesting stimulates more bud production and greater future yields.
• Second year: Extend harvest to 4–6 weeks.
• Third year and beyond: Harvest for 6–8 weeks.

Spears emerge when soil temperature reaches 50°F. Early in the season, harvest every 2–4 days; as air temperatures rise, harvest once or twice daily, picking 5- to 7-inch spears before tips fern out. Stop harvesting when ¾ of spears are less than ⅜ inch in diameter.

Post-Harvest Weed Control

When harvest ends, snap all remaining spears at ground level. Apply ½ lb. ammonium nitrate fertilizer per 50 feet of row. Since no asparagus foliage is above ground, spray the patch with glyphosate (click for sources) to kill existing weeds. New spears will emerge, fern out, and form a dense canopy that shades out future weed growth.

This integrated approach—proper harvesting followed by targeted herbicide application—keeps asparagus beds productive and weed-free for years.