If you’re planning a perennial vegetable patch, asparagus is a fantastic choice. Knowing how far apart do you plant asparagus is the first critical step to a healthy, productive bed that lasts for decades. Getting the spacing right gives the plants room to establish their extensive root systems and ensures good air circulation, which is key to preventing disease.
This guide will walk you through the optimal spacing for planting asparagus, whether you’re starting with seeds or crowns. We’ll cover why it matters, the exact measurements, and how to lay out your bed for maximum yield.
How Far Apart Do You Plant Asparagus
The standard and recommended spacing for asparagus is 18 inches apart in rows that are 5 feet apart. This spacing is not arbitrary; it’s the result of generations of gardening experience. Each asparagus plant needs significant space belows ground for its large, fleshy roots, called crowns, to spread out.
Above ground, the ferns can grow four to six feet tall and just as wide. Giving them this 18-inch spacing within the row prevents overcrowding. The wide 5-foot row spacing allows you to walk between the rows for weeding and harvesting without compacting the soil around the plants. It also lets the ferns arch over without tangling with the next row, ensuring each plant gets plenty of sunlight.
Why Proper Asparagus Spacing is Non-Negotiable
Planting asparagus too close is a common mistake with long-term consequences. These plants are an investment, often productive for 15 years or more. Crowding them creates problems that are hard to fix later.
First, competition for nutrients and water becomes intense. This leads to weaker plants and thinner spears over time. Second, poor air circulation between dense foliage creates a humid environment that fungal diseases, like asparagus rust, love. Adequate spacing is your best defense.
Finally, harvesting becomes a real chore. Trying to find and cut spears in a tangled thicket is difficult and you might damage emerging shoots.
Spacing for Asparagus Crowns vs. Seeds
Most gardeners start with one-year-old crowns, as they give you a harvestable crop much sooner. For crowns, dig a trench. The spacing within that trench should be 12 to 18 inches between each crown. Many experts now favor the wider 18-inch spacing for long-term plant health.
If you’re starting from seed, you have more flexibility initially. Seeds are often started in a nursery bed or containers and then transplanted. When the seedlings are ready to move to their permanent home, space them at the same 18 inches apart in rows 5 feet apart. Remember, plants grown from seed need an extra year of growth before you begin harvesting.
How to Plant Asparagus Crowns with Correct Spacing
Follow these steps for success. The process is simple but requires a bit of patience.
- Choose a sunny, well-drained site with fertile soil. Asparagus loves sun.
- Dig a trench that is 12 inches wide and 6 to 8 inches deep. If planting multiple rows, ensure the trenches are 5 feet apart from center to center.
- Create a small mound of soil down the center of the trench, about 2 inches high.
- Place the asparagus crowns on top of the mound, spacing them 18 inches apart. Drape the roots down over the sides of the mound.
- Cover the crowns with just 2 inches of soil. As the shoots grow through the summer, gradually fill in the trench with more soil until it is level.
Layout Ideas for Your Asparagus Bed
The traditional single-row method is effective, but not your only option. Here are two common layouts.
Single Rows: This is the classic method described above. It’s perfect for long, dedicated beds and makes harvesting very straightforward. Just be sure to keep up with weeding in the 5-foot alleyways.
Wide Beds: Instead of single rows, you can plant a wide raised bed. In a bed that is 4 to 5 feet wide, you can plant two staggered rows. Space the plants 18 inches apart in all directions. This intensive method yeilds more in a smaller space but requires excellent soil fertility.
Common Spacing Mistakes to Avoid
Even with the right numbers, it’s easy to slip up. Watch for these pitfalls.
- Eyeballing the Distance: Always use a measuring tape or a marked stick. Guessing usually results in plants that are too close.
- Forgetting Final Size: It’s tempting to plant closely when the crowns are small. Visualize the full-sized ferns to resist this urge.
- Neglecting Row Spacing: Squeezing rows together to fit more plants is counterproductive. You’ll regret it when the ferns form an impenetrable wall.
- Poor Soil Prep: Spacing alone won’t save plants in poor soil. Amend the entire bed with compost before planting, not just the planting holes.
Caring for Your Newly Spaced Asparagus Plants
Proper care in the first two years is crucial. Resist harvesting any spears in the first year after planting crowns. In the second year, you can harvest for about two weeks. This allows the plant to build a strong root system.
Keep the bed consistently watered, especially in the first season. Mulch heavily with straw or shredded leaves to suppress weeds and retain moisture. Weeds are a major competitor for young asparagus. Hand-pull them carefully to avoid disturbing the shallow roots.
In the fall, after the ferns have turned yellow, you can cut them down to the ground. Some gardeners prefer to leave them until late winter to provide a bit of winter protection for the crown.
When and How to Divide Overcrowded Asparagus
If you inherit an old, overcrowded bed, you can revive it by division. The best time for this is in early spring, just as the first spears appear or in late fall after the ferns die back.
Carefully dig up the entire clump with a garden fork. You’ll see a mass of interconnected crowns. Use a sharp knife or spade to cut the clump into sections, each with several healthy buds and plenty of roots. Replant these divisions immediately at the proper 18-inch spacing in a newly prepared bed.
FAQ: Asparagus Planting Spacing
Can I plant asparagus 12 inches apart?
While 12 inches is the minimum often listed, 18 inches is better for long-term plant vigor and disease prevention. The slightly wider spacing is worth the extra patience.
How much asparagus do I need to plant for a family of four?
A good starting point is 20-25 crowns. This should provide a substantial harvest each spring. Remember, you’ll be harvesting from these same plants for many years, so it’s okay to start with a manageable number.
What happens if asparagus is planted too close together?
The plants will compete for resources, leading to smaller, thinner spears. They will be more susceptible to disease due to poor air flow, and the overall lifespan of the bed will likely be shortened.
How deep should asparagus crowns be planted?
The initial planting depth is shallow—just 2 inches of soil over the crown. The trench method, where you gradually fill soil in as the plant grows, is preferred because it allows the stems to strengthen.
Can I grow asparagus in a raised bed?
Absolutely. Raised beds offer excellent drainage, which asparagus requires. Just ensure the bed is at least 12-18 inches deep to accommodate the deep roots and that you maintain the 18-inch spacing between plants.
Getting the spacing right when you first plant is the most important gift you can give your asparagus. It sets the stage for years of reliable, abundant harvests. Take the time to measure carefully, prepare the soil well, and resist the temptation to overcrowd. Your future self, enjoying those first spring spears, will thank you for the effort.