Best Asparagus Fertilizer (16-10-13): High Nitrogen Slow Release with Sulfur & Magnesium for Maximum Spear Production Buy on Old Cobblers Farm
Old Cobblers Farm™ Wicked Growth Asparagus Fertilizer 16-10-13
by Wicked Growth — Littleton, NH
16% Nitrogen for Fern Growth
After harvest ends, asparagus ferns are the energy factory. More nitrogen = taller, denser ferns = more photosynthesis = more energy stored in the crown = more spears next spring.
Polymer-Coated Slow Release
Purkote technology feeds nitrogen gradually over weeks during the critical fern-growth period. No surge-and-crash — steady nutrition through the entire recharge window.
Sulfur & Magnesium from Langbeinite
Potassium magnesium sulphate delivers sulfur for protein synthesis and magnesium for chlorophyll — both critical for maximizing the photosynthetic output of asparagus ferns.
Post-Harvest Timing is Critical
Apply immediately after your last spear harvest when ferns start growing. This is when asparagus has the highest nutrient demand. A second application in late summer extends the recharge window.
250–333 sq ft Per Bag
At 1.5–2 lbs per 100 sq ft, one 5 lb bag covers a full-sized asparagus bed. Most home growers need just one bag per application.
13% Potassium for Crown Energy
Potassium regulates carbohydrate transport from ferns to crowns. Adequate K ensures the energy produced by ferns actually gets stored where it matters — in the root crown.
New & Established Beds
Works for newly planted asparagus crowns building their root system and for established beds maximizing annual spear production. Adjust rate by bed age.
Trusted by 20,000+ Growers
Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.
| NPK Ratio | 16-10-13 |
| Derived From | Urea (20%), Purkote / Polymer Coated Urea (10%), Monoammonium Phosphate (20%), Potassium Chloride / Muriate of Potash (20%), Potassium Magnesium Sulphate (10%), Silicon Dioxide (20%) |
| Item Form | Slow-release granular (polymer coated) |
| Release Speed | Slow-release |
| Application Rate | 1.5–2 lbs / 100 sq ft |
| Method | Broadcast over asparagus bed |
| Frequency | 2x per season (after last spring harvest + late summer) |
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb |
| Supports | All asparagus varieties — Jersey Knight, Jersey Giant, Mary Washington, Purple Passion, Millennium, UC 157 |
| Setups | Asparagus beds, raised beds, asparagus trenches, field rows |
| Feature | Old Cobblers Farm™ Wicked Growth Asparagus Fertilizer 16-10-13 | Asparagus Alive! | Slow-Release Fertilizer | Premium Gold All Purpose | Organics Vegetable Food | Veg & Tomato Spikes | All Purpose Plant Food | 13-13-13 All Purpose | Performance Organics | Garden-Tone | Happy Frog Tomato & Veg |
|---|---|---|---|---|---|---|---|---|---|---|---|
| NPK | 16-10-13 | Proprietary | 6-4-2000 | 4-4-2004 | 3-4-2004 | 2-7-2004 | 10-10-10 | 13-13-13 | 11-3-2008 | 3-4-2004 | 5-7-2003 |
| Phosphorus | 10.0% | 0.0% | 4.0% | 4.0% | 4.0% | 7.0% | 10.0% | 13.0% | 3.0% | 4.0% | 7.0% |
| Potassium | 13.0% | 0.0% | 0.0% | 4.0% | 4.0% | 4.0% | 10.0% | 13.0% | 8.0% | 4.0% | 3.0% |
| Form | Slow-release granular (polymer coated) | ||||||||||
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb | 2 lb | 32 lb | 4 lb, 12 lb | 4 lb | 50 count | 40 lb | 40 lb | 2.5 lb | 8 lb, 27 lb | 4 lb |
| Release Speed | Slow-release |
Asparagus Alive!
Slow-Release Fertilizer
Premium Gold All Purpose
Organics Vegetable Food
Veg & Tomato Spikes
All Purpose Plant Food
13-13-13 All Purpose
Performance Organics
Garden-Tone
Happy Frog Tomato & Veg
16% Nitrogen for Fern Growth
After harvest ends, asparagus ferns are the energy factory. More nitrogen = taller, denser ferns = more photosynthesis = more energy stored in the crown = more spears next spring.
Polymer-Coated Slow Release
Purkote technology feeds nitrogen gradually over weeks during the critical fern-growth period. No surge-and-crash — steady nutrition through the entire recharge window.
Sulfur & Magnesium from Langbeinite
Potassium magnesium sulphate delivers sulfur for protein synthesis and magnesium for chlorophyll — both critical for maximizing the photosynthetic output of asparagus ferns.
Post-Harvest Timing is Critical
Apply immediately after your last spear harvest when ferns start growing. This is when asparagus has the highest nutrient demand. A second application in late summer extends the recharge window.
