11 Tips for Growing 10-Foot Asparagus
Growing towering asparagus may seem like a garden fantasy, but with the right techniques and care, asparagus plants can reach incredible heights — sometimes up to 10 feet tall during their fern stage. While the edible spears typically grow to 6–10 inches before harvest, the plant’s full potential as a perennial can be truly magnificent. Here are 11 expert tips to help you grow robust, healthy asparagus that could reach towering heights in its fern phase.
1. Choose the Right Variety
Not all asparagus is created equal. Some varieties naturally grow taller than others. Look for vigorous cultivars like Jersey Giant, Purple Passion, or Millennium — these are known for their productivity and vigorous growth, including tall ferns post-harvest.
2. Start with Crowns, Not Seeds
Asparagus can be grown from seed, but starting with one-year-old crowns gives you a major head start. Crowns are more resilient, establish quickly, and will produce taller plants faster than seeds.
3. Plant in Deep, Well-Drained Soil
Asparagus roots grow deep and need well-aerated, nutrient-rich soil. Dig trenches 12–18 inches deep and amend the soil with compost and aged manure. Good drainage is essential to prevent root rot and encourage deep rooting, which supports taller fern growth.
4. Provide Full Sun
Asparagus loves sunlight. Choose a site that receives at least 6–8 hours of direct sunlight per day. More sun means more energy for photosynthesis, which in turn encourages taller, healthier ferns.
5. Amend the Soil with Organic Matter
Add compost, worm castings, and aged manure regularly to improve soil fertility. A healthy, organic-rich soil environment provides essential nutrients that asparagus needs to thrive and reach its full height potential.
6. Maintain Soil pH Between 6.5 and 7.5
Asparagus grows best in slightly acidic to neutral soil. Test your soil’s pH and amend with lime if it’s too acidic. Balanced pH ensures optimal nutrient uptake and supports strong, vigorous growth.
7. Water Consistently and Deeply
Asparagus needs about 1–2 inches of water per week during the growing season. Deep watering encourages deeper root growth, which can result in taller, more resilient plants during the ferning stage.
8. Fertilize Throughout the Season
Apply a balanced fertilizer in early spring as the spears emerge, and again after harvesting is complete. Use a low-nitrogen fertilizer (like 5-10-10) to promote root and fern development rather than excessive spear production.
9. Support the Ferns
As asparagus ferns reach for the sky, they can become top-heavy and flop over. Use stakes or cages to support the tall ferns and prevent them from breaking or bending under their own weight.
10. Control Weeds Aggressively
Weeds compete with asparagus for nutrients and water. Keep the bed weed-free by mulching heavily and hand-pulling weeds as needed. Less competition means more energy for the asparagus to grow tall and strong.
11. Be Patient and Persistent
Asparagus is a perennial plant that takes time to establish. You may not see maximum height or yield in the first couple of years. With consistent care and patience, your plants will reward you in future seasons with towering growth and abundant harvests.
With the right combination of soil preparation, sunlight, watering, and maintenance, asparagus can become one of the most impressive plants in your garden. These 11 tips will set you on the path to growing lush, 10-foot asparagus ferns that are as beautiful as they are bountiful.
