How to Grow Asparagus from Seed (Step-by-Step Guide for Beginners)
Want to grow asparagus from seed in your own garden? This complete guide covers everything you need to know—from selecting the best varieties to transplanting seedlings and harvesting spears. Whether you're a beginner gardener or looking for a cost-effective alternative to crowns, this step-by-step tutorial will help you establish a productive asparagus bed that can thrive for 15 to 20 years.
Growing asparagus from seed may take time, but it's a budget-friendly and rewarding way to start your asparagus patch. Compared to planting crowns, starting from seed allows for stronger root development and greater resistance to pests and diseases, giving you a healthy, long-lasting crop.
Best Soil for Growing Asparagus
Asparagus grows best in fertile, well-drained soil with a slightly acidic to neutral pH (6.5 to 7.5). Improve your soil by adding well-rotted compost or aged manure before planting. Avoid waterlogged areas, as asparagus roots are prone to rot in poorly drained soil.
Top Asparagus Varieties to Grow from Seed
Choose from the following asparagus seed varieties for best results:
Mary Washington – A heritage, open-pollinated variety known for its resilience and reliability.
Ariane F1 Hybrid – These include vigorous, disease-resistant types bred for uniform spears and higher yields.
When and How to Start Asparagus Seeds Indoors
Start your asparagus seeds indoors in late spring, around 8–10 weeks before your last expected frost date. This gives the young plants a head start before transplanting outdoors.
How to Germinate Asparagus Seeds Successfully
Soak the seeds in warm water for 12–24 hours to improve germination.
Sow 1–2 cm deep in seed trays or pots filled with seed-starting mix.
Maintain temperatures above 21°C (70°F) in a warm indoor area or greenhouse.
Germination typically takes 2 to 8 weeks, so be patient and keep soil moist.
How to Transplant Asparagus Seedlings Outdoors
Once seedlings develop a few strong leaves:
Harden them off by gradually introducing them to outdoor conditions.
Dig trenches 45 cm (18 inches) apart in full sun.
Plant seedlings 30–45 cm (12–18 inches) apart, in staggered rows.
As the plants grow, gradually fill the trench with soil to promote strong crown development.
Caring for Young Asparagus Plants
Water consistently, especially during dry periods.
Weed regularly to reduce competition.
Mulch to conserve moisture and suppress weeds.
Apply a balanced fertiliser each spring to support root and spear growth.
When and How to Harvest Asparagus Spears
Avoid harvesting too early—young plants need time to establish for long-term productivity.
Year 1: No harvesting—focus on root development.
Year 2: Very light harvest (if plants are strong).
Year 3: Begin harvesting for 2–3 weeks.
Year 4 and beyond: Full harvest for 6–8 weeks in spring.
After the harvest season, apply compost or a light fertiliser and keep the bed weed-free to encourage healthy ferns for growth.