When to Cut Asparagus: The Definitive Guide for Gardeners
Asparagus is typically ready to harvest in the spring, once spears are at least 6-8 inches tall and about pencil-thick; however, when you start and stop harvesting each year is crucial for the long-term health and productivity of your asparagus patch.
Asparagus: A Perennial Delight
Asparagus ( Asparagus officinalis) is a perennial vegetable prized for its tender, flavorful spears. Unlike annual vegetables that need to be replanted each year, asparagus can produce for 15-20 years or even longer with proper care. Successful asparagus cultivation hinges on understanding its growth cycle and, crucially, knowing when to cut.
Why Timing Matters: Feeding the Crown
The asparagus plant has a crown located underground. The spears that we harvest are actually the new shoots emerging from this crown. The plant needs time to replenish its energy reserves after each harvest. Allowing some spears to develop into ferns is essential for photosynthesis and carbohydrate storage, which fuels the crown for future growth and spear production. Premature or excessively long harvests deplete these reserves, weakening the plant and reducing yields in subsequent years.
The Harvesting Process: A Step-by-Step Guide
Here’s how to harvest asparagus spears correctly:
- Wait for the Right Size: Spears should be at least 6-8 inches tall and about pencil-thick (approximately 3/8 inch in diameter).
- Harvesting Method: Use a sharp knife or asparagus knife to cut the spear at or just below the soil surface. Avoid damaging the crown or nearby spears. You can also snap off the spear near the base, but this can leave a stub that may attract pests.
- Frequency of Harvest: During peak season, you may need to harvest every day or every other day.
- Handle with Care: Asparagus spears are delicate, so handle them gently to avoid bruising.
Knowing When to Start Harvesting: Patience is Key
The most crucial factor in ensuring a healthy and productive asparagus bed is patience.
- Year 1 (Planting Year): Do not harvest any spears. Let them all fern out to strengthen the crown.
- Year 2: A very light harvest of only a few spears for a short period (2-3 weeks) may be possible, if the plants are strong. Err on the side of caution.
- Year 3: You can begin a more substantial harvest, but still limit it to 6-8 weeks.
- Year 4 and Beyond: Full harvesting is possible, but remember to stop when the spears become thin or production slows down.
Determining the End of the Harvest Season: Letting it Fern
Knowing when to stop harvesting is just as important as knowing when to start. The asparagus plant needs time to replenish its energy reserves. A good rule of thumb is to stop harvesting when the spears start to become thinner, which indicates the plant is beginning to struggle. This generally occurs in late spring or early summer (depending on your climate). Allow the remaining spears to fern out and grow tall to promote photosynthesis and carbohydrate storage.
Climate Considerations: Adjusting to Your Region
The timing of the asparagus harvest varies depending on your climate:
| Climate Zone | Approximate Harvesting Period |
|---|---|
| Colder Climates | Late April/Early May to late June/Early July |
| Temperate Climates | Early April to mid-June |
| Warmer Climates | Late March to late May |
These are general guidelines. Pay attention to the spears’ thickness and overall plant vigor to determine the best harvesting schedule for your specific location.
Common Mistakes to Avoid: Asparagus Harvesting Pitfalls
Here are some common mistakes to avoid when harvesting asparagus:
- Harvesting too early: This weakens the plant and reduces future yields.
- Harvesting too late: This allows the spears to become tough and woody.
- Damaging the crown: Be careful when cutting the spears to avoid injuring the underground crown.
- Neglecting weed control: Weeds compete with asparagus for nutrients and water.
- Not providing adequate water: Asparagus needs consistent moisture, especially during the growing season.
- Harvesting for too long: Extending the harvest season too far depletes the plant’s energy reserves.
Frequently Asked Questions (FAQs)
Is it okay to eat asparagus ferns?
No, asparagus ferns are not edible and contain compounds that can cause digestive upset. They are important for the plant’s health and should be allowed to grow after the harvesting season.
What does asparagus look like when it’s ready to harvest?
Ready-to-harvest asparagus spears are straight, tightly closed at the tip, and approximately pencil-thick (about 3/8 inch in diameter) and 6-8 inches tall. If the tips start to open up or the spears become very thin, it’s time to stop harvesting.
Why are my asparagus spears so thin?
Thin asparagus spears can be caused by several factors: over-harvesting, lack of nutrients, insufficient water, weed competition, or disease. Ensure you’re providing adequate water and fertilizer, controlling weeds, and allowing the plants to fern out after the harvest season.
How often should I fertilize my asparagus bed?
Fertilize your asparagus bed in the early spring before the spears emerge and again after the harvest season when the ferns are growing. Use a balanced fertilizer or compost.
Can I harvest asparagus in the fall?
No, you should not harvest asparagus in the fall. The plant needs to focus on storing energy in the crown for the winter. Harvesting in the fall will weaken the plant and reduce yields in the spring.
What if I planted my asparagus from seed? Does the harvest timing change?
Yes, asparagus grown from seed will take longer to mature than those grown from crowns. Do not harvest any spears for the first two years. A light harvest may be possible in the third year, and a full harvest in the fourth year.
What’s the best time of day to harvest asparagus?
Harvest asparagus in the morning when the spears are firm and cool. This will help them stay fresh longer.
How do I store harvested asparagus?
To store harvested asparagus, wrap the ends in a damp paper towel and place them in a plastic bag in the refrigerator. This will help them stay fresh for several days. You can also stand them upright in a jar with a little water.
What should I do with my asparagus bed in the winter?
In the late fall, after the ferns have turned brown, cut them down to the ground. Apply a layer of mulch to protect the crown from freezing temperatures.
My asparagus bed is very old. How do I know if it’s time to replant?
If your asparagus bed is producing very thin spears and yields are significantly declining, it may be time to replant. Consider starting a new bed in a different location.
Can I move my asparagus bed to a new location?
Yes, you can move an asparagus bed, but it’s a labor-intensive process. Dig up the crowns carefully in the fall or early spring before new growth appears. Replant them in a well-prepared location with good drainage and plenty of organic matter.
What diseases affect asparagus, and how can I prevent them?
The most common diseases affecting asparagus are asparagus rust and Fusarium crown and root rot. To prevent these diseases, ensure good air circulation, avoid overwatering, and use disease-resistant varieties. Remove and destroy any infected plants.