Asparagus is a perennial crop that can produce spears for fifteen years or more. Because of this long lifespan, the original planting site may eventually become unsuitable due to crowding, reduced sun exposure, or changes in soil condition. When the need to relocate an established patch arises, transplanting asparagus in the fall is often the preferred time. Successfully moving these long-lived plants, which grow from underground structures called crowns, depends on precise timing and careful preparation of both the plant and its new home.
Seasonal Timing: Why Fall is Preferred
The optimal time for relocating asparagus crowns aligns with the plant’s natural resting period, known as dormancy. Asparagus ferns spend the summer months storing carbohydrates in their fleshy root systems to fuel the next spring’s harvest. This energy storage process is necessary for the plant’s long-term viability.
When the foliage naturally yellows and dies back in the autumn, it signals that the plant has entered dormancy. Transplanting during this phase minimizes shock because the plant is not actively producing new spears or sustaining a large fern structure. Moving the crown in late fall provides a long window for the roots to heal and establish themselves before spring growth begins. This establishment period, free from the stress of summer heat or drought, increases the transplant’s survival rate and future productivity.
Preparing the New Site and Existing Crowns
Successful asparagus relocation requires thorough preparation of the new bed. Asparagus needs a site that receives full sun and offers excellent drainage, as the crowns are susceptible to rot in soggy soil conditions. Since the deep root system can extend several feet, the soil must be loose and well-prepared to accommodate this growth.
To improve the soil structure and fertility, the new bed should be dug out and amended with organic matter, such as compost or aged manure. Asparagus thrives best in soil that is neutral to slightly acidic, with a target pH range between 6.5 and 7.0. It is advisable to conduct a soil test in advance to determine if lime or other amendments are necessary to adjust the pH before planting. The planting area should be free of perennial weeds, as they compete with newly established crowns for nutrients and water.
Preparation of the existing plant must occur once the ferns have fully turned yellow or brown, indicating the plant has reached peak dormancy. At this point, the dead foliage should be cut back to within a few inches of the ground. Leaving a short stub helps to clearly mark the location of the crown before beginning the digging process.
Step-by-Step Transplanting
The removal of the asparagus crown is the most delicate stage of the process. Begin by digging a wide circle, 8 to 10 inches beyond where the old foliage was clustered, to capture as much of the extensive root system as possible. Asparagus roots are fleshy and deep, so the digging depth may need to reach twelve inches to lift the entire clump.
Once loosened, the crown and root ball should be lifted and kept moist to prevent the roots from drying out before replanting. If the original clump is very large or overcrowded, it can be divided using a sharp spade or knife, ensuring that each new section retains a healthy portion of the crown and several buds. While division can rejuvenate old plants, it increases the risk of transplant shock, so handle the separated crowns with care.
The new planting trench should be six to eight inches deep and wide enough to accommodate the spread of the roots. A small, mounded ridge of soil can be created down the center of the trench, upon which the crown is set, allowing the roots to be draped evenly down both sides. Cover the crown with an initial layer of two to three inches of soil, avoiding the complete filling of the trench at this stage. Adding a high-phosphate fertilizer to the trench before setting the crown may help reduce transplant shock and encourage root development.
Post-Transplant Care and Harvest Expectations
The new bed must be watered thoroughly after transplanting to settle the soil around the relocated crowns. The area should not be allowed to become waterlogged. A thick layer of organic mulch, such as straw or aged leaves, should then be applied over the bed to insulate the crowns during winter.
The remaining soil in the trench will be added gradually as the crown establishes itself in the following growing season. It is important to monitor the bed throughout the winter for signs of “heaving,” where the freeze-thaw cycle pushes the crown out of the ground, and gently push any exposed crowns back into place. The relocation process resets the plant’s establishment clock, delaying harvesting. The crown needs time to recover and rebuild its carbohydrate reserves. Consequently, no spears should be harvested for a minimum of one to three full growing seasons after the fall move.