What fertilizer works best?
Written by
Julia Anderson
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.The fertilization of asparagus is minimized when we have an appreciation of its seasonal needs. The use of synthetic salts or blends with high-salt concentration kills roots, I lost 15 plants before I converted to organic products. Asparagus crowns that are healthy need phosphorus for root development; nitrogen for growth of ferns; and potassium for winter hardening. Timing fertilizer applications with growth stages is paramount.
Application Tips
- Test soil pH before adding amendments
- Water deeply after applying dry fertilizers
- Avoid high-nitrogen formulas that promote fern overgrowth
Mistakes to Avoid
- Using fresh manure (burns plants)
- Overapplying phosphorus (locks out zinc)
- Fertilizing during drought conditions
Use bone meal 6 weeks before spear emergence. Its phosphorus is slow-release as well and won't build up salt. My abed in Massachusetts had a 30% increase in productivity due to this method. Then apply manure in the fall, it will protect the crowns from -20% winters, basically packing them in a thermal blanket.
Rotation Strategy
- Plant nitrogen-fixers post-harvest
- Avoid nightshades for 3 years
- Test soil annually for micronutrients
Compost Tea
- Apply monthly during fern growth
- Use 1:10 tea-to-water ratio
- Strain to prevent clogging drip lines
After noticing that ferns were 20% thicker, seaweed extract became my post-harvest secret. Mix 1 ounce per gallon and spray the asparagus lightly and generously in the morning to allow for good absorption. Avoid synthetic products that use weed-and-feed products, as their herbicides will remain in the soil for years and inhibit growth. If you've built healthy asparagus beds, it will be worth the wait,sweet spears can last decades.
Read the full article: How to Grow Asparagus: Expert Tips for Perennial Success
