Asparagus is a perennial vegetable, prized for being one of the first fresh crops available each spring. The quality of the harvested spear is determined by how and when it is removed from the garden and prepared for the kitchen. Understanding the precise location to make a cut, both during the initial harvest and before cooking, ensures you maximize the edible portion and maintain the health of the underground plant.
When to Harvest Asparagus: Timing and Spear Size
The timing of the harvest begins in the third year after planting to allow the underground crown to fully establish. Spears emerge in the spring when soil temperatures consistently rise above 50 degrees Fahrenheit. Spears ready for harvest should be between six and ten inches tall.
The ideal diameter of the spear is about the width of a pencil, or roughly a half to three-quarters of an inch thick. Harvesting spears within this size range prevents them from becoming fibrous. If a spear is allowed to grow too tall, its compact tip will begin to “fern out,” signaling that it has passed the point of peak tenderness. During the peak season, spears should be checked and harvested every one to three days, as warm weather causes rapid growth.
Harvesting Techniques: Cutting vs. Snapping
Once a spear has reached the correct height, the cut is made near the soil line. The cutting method involves using a sharp knife or shears to make a clean incision at ground level or slightly below it. Cutting approximately one inch below the soil surface at a slight angle maximizes the spear’s length and potentially increases its shelf life by including the white tissue, which is less prone to water loss.
Care must be taken with a knife to avoid accidentally damaging the underground crown or the delicate, developing spears that are not yet visible. Snapping the spear by hand is an alternative method that reduces the risk of injuring the main plant. The spear naturally breaks at the point where the tender, succulent tissue meets the tough, woody base near the soil. Snapping the spear removes only the edible portion, leaving the tougher stub to dry out naturally.
Preparing Asparagus: Removing the Woody Base
After harvest, the base still contains tissue that is tough and unpleasant to eat, requiring preparation before cooking. This woody texture is due to lignification, which involves the deposition of a rigid polymer called lignin into the cell walls. Lignification continues after harvest, beginning at the cut end and moving upward, necessitating the removal of the base.
The most common method to find the edible limit is the snap test: hold the spear near the center and bend the bottom end until it breaks cleanly. The spear fractures where the tender tissue ends and the tough, lignified base begins. A more efficient and uniform approach is to use a knife to trim the ends.
To trim with a knife, align all the spears on a cutting board so the tips are even, and then slice off the bottom inch or two. This cut should be made just above the pale, whitish section of the stalk where the color transitions to a vibrant green. Trimming with a knife minimizes waste and provides a neater presentation compared to the snap method. Once trimmed, the spears should be used immediately or stored in the refrigerator to slow the ongoing lignification process.