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Old Cobblers Farm™ Wicked Growth 16-10-13 Fertilizer – Balanced Nutrition

High-nitrogen 16-10-13 fertilizer with slow-release technology and 7% calcium. Application rates for gardens, lawns & crops from Old Cobblers Farm.

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OUR STORY

This 16-10-13 formula is the same blend as Old Cobblers Farm's Asparagus Fertilizer—both are produced by Green Mountain Fertilizer using identical ingredients and ratios. The six-ingredient composition (urea, Purkote polymer-coated urea, monoammonium phosphate, muriate of potash, potassium magnesium sulfate, silicon dioxide) provides higher total nutrient content than standard balanced fertilizers.

The dual nitrogen delivery system combines urea for immediate availability with Purkote for sustained release, matching how plants actually use nitrogen—in steady doses over time rather than one massive spike. The 7% calcium from the mineral components is exceptionally valuable as a secondary nutrient, particularly for crops prone to calcium-related quality issues like blossom-end rot.

NPK

16-10-13

Type

Non-Organic

Derived From

Urea, Purkote (Polymer Coated Urea), Monoammonium Phosphate, Potassium Chloride (Muriate of Potash), Potassium Magnesium Sulfate, Silicon Dioxide. Also provides 2% Sulfur, 7% Calcium, 1% Magnesium.

Best For

Brand

Wicked Growth

NPK Breakdown

N

Provides 16% nitrogen (from urea and polymer-coated urea for extended release) to fuel vigorous growth. The Purkote slow-release component feeds for 6-8 weeks per application, reducing the total number of applications needed per season.

P

Delivers 10% phosphorus (from monoammonium phosphate) to promote deep root development and support establishment of new plantings and perennial crowns

K

Supplies 13% potassium (from muriate of potash and potassium magnesium sulfate) to strengthen cell walls, improve disease resistance, and enhance winter hardiness

What Is It ?

The 16-10-13 fertilizer is a nitrogen-forward balanced blend designed for crops and landscapes that demand higher nitrogen inputs while still receiving complete NPK nutrition with valuable secondary nutrients. With 16% nitrogen—featuring both fast-acting urea and polymer-coated slow-release urea (Purkote)—each application feeds for 6-8 weeks, reducing the total number of applications per season. The 10% phosphorus provides strong root support and flower development, while 13% potassium drives quality and stress tolerance. Secondary nutrients include 2% sulfur, 7% calcium, and 1% magnesium—the 7% calcium content is notably high and particularly valuable for crops prone to calcium-related disorders. This formula delivers 39% combined NPK per pound, more than standard 10-10-10 (30% combined), meaning more nutrition per application. This is the same formulation as Old Cobblers Farm™ Asparagus Fertilizer, available as a general-purpose option for gardeners growing a wide range of nitrogen-demanding crops. Manufactured by Green Mountain Fertilizer in Milton, Vermont.

When To Apply ?

Apply using standard broadcast methods. For garden beds, incorporate 0.5-1.5 lbs per 100 sq ft into soil before planting. For established perennials, broadcast over the bed surface in early spring and water in. For lawns, use a calibrated spreader at 3-5 lbs per 1,000 sq ft. The polymer-coated urea means each application feeds for 6-8 weeks, so most crops need only 2-3 applications per season. For commercial production, apply 100-200 lbs per acre. This is the same formulation as Old Cobblers Farm™ Asparagus Fertilizer—apply using the same rates and methods.

How to Apply ?

1. Soil Test

Test soil before the season to determine nutrient needs. This balanced formula works well for general-purpose feeding.

2. Garden Broadcast

Broadcast 0.5–1.5 lbs per 100 sq ft before planting or in early spring for established beds.

3. Lawn Rate

For lawns, apply 3–5 lbs per 1,000 sq ft with a calibrated broadcast or drop spreader for even coverage.

4. Side-Dress

Side-dress nitrogen-hungry crops (corn, leafy greens, brassicas) every 4–6 weeks during the growing season.

5. Water In

Water thoroughly after each application to prevent burn and activate nutrient release.

6. Monitor

Monitor crop response and adjust rates accordingly. Excessive leaf growth with poor fruiting may indicate too much nitrogen.

7 Lawn Rate

For lawns, apply 3–5 lbs per 1,000 sq ft with a calibrated broadcast or drop spreader for even coverage.

How To Store

Wear protective gloves and eye protection during handling. Avoid breathing dust—use a NIOSH-approved dust respirator if applying in windy conditions. Wash hands thoroughly after handling. Store in a cool, dry, well-ventilated area protected from weather. Slightly reactive with oxidizing agents, metals, alkalis, and moisture—keep sealed when not in use. Prevent entry to sewers and surface waters. Keep out of reach of children and pets.

FAQs

1. What is 16-10-13 fertilizer used for?

16-10-13 fertilizer is a high-nitrogen, balanced formula designed for plants that need vigorous growth combined with strong root systems and stress resistance. The elevated nitrogen (16%) drives lush foliage and rapid canopy development, phosphorus (10%) supports deep root growth and crown structure, and potassium (13%) enhances disease resistance and environmental tolerance. It is especially effective for asparagus, turfgrass, and heavy-feeding crops that demand sustained nitrogen throughout the growing season. Old Cobblers Farm™ Wicked Growth 16-10-13 Fertilizer with added sulfur and magnesium is a premium option for targeted plant nutrition.

2. Is 16-10-13 good for asparagus?

Yes, 16-10-13 is an excellent fertilizer for asparagus. The high nitrogen content encourages strong fern growth after the harvest season, which is critical for building carbohydrate reserves in the crown for next year's spear production. Phosphorus supports the deep root systems asparagus needs as a perennial crop, and potassium improves stress tolerance and overall plant resilience. When formulated with added sulfur and magnesium, 16-10-13 optimizes nutrient uptake and chlorophyll production. Old Cobblers Farm™ Wicked Growth Asparagus Fertilizer 16-10-13 is specifically designed for both new and established asparagus beds.

3. How much 16-10-13 fertilizer should I apply?

Application rates for 16-10-13 fertilizer depend on the crop. For asparagus, apply in early spring before spears emerge and again in late summer after the harvest season. For lawns, apply 5–8 pounds per 1,000 square feet during active growth. For general garden use, broadcast 2–3 pounds per 100 square feet and incorporate into the top few inches of soil. Always water thoroughly after application. The elevated nitrogen content means less product is needed to achieve the same nitrogen input compared to lower-analysis fertilizers. Old Cobblers Farm™ Wicked Growth 16-10-13 is fast-acting and effective when watered in.

4. What does sulfur and magnesium do in fertilizer?

Sulfur and magnesium are essential secondary nutrients that enhance plant growth and nutrient uptake. Sulfur is critical for amino acid synthesis, enzyme function, and chlorophyll formation — without adequate sulfur, plants cannot efficiently use nitrogen. Magnesium is the central atom in the chlorophyll molecule and directly drives photosynthesis. Together, they help plants produce more energy, maintain greener foliage, and utilize primary nutrients (N-P-K) more effectively. Old Cobblers Farm™ Wicked Growth 16-10-13 Fertilizer includes both sulfur and magnesium to maximize nutrient efficiency and promote healthy, vibrant plant growth.

5. Can I use 16-10-13 on my lawn?

Yes, 16-10-13 is well-suited for lawns, particularly cool-season turfgrass that responds well to higher nitrogen applications. The 16% nitrogen promotes thick, green growth and canopy density, phosphorus builds strong root systems for better drought tolerance, and potassium strengthens the turf against disease, heat, and traffic. Apply 5–8 pounds per 1,000 square feet during spring or fall for best results. Old Cobblers Farm™ Wicked Growth 16-10-13 Fertilizer delivers premium, high-performance nutrition for lawns that demand more than a basic fertilizer can provide.

6. When should I fertilize asparagus?

Fertilize asparagus twice per year — first in early spring before spears begin to emerge, and again in late summer or early fall after the harvest season ends and ferns are actively growing. The spring application fuels spear production, while the fall application supports fern growth and carbohydrate storage in the crown for next year's harvest. Avoid fertilizing during the active harvest period. For newly planted crowns, apply at planting and again mid-summer. Old Cobblers Farm™ Wicked Growth Asparagus Fertilizer 16-10-13 with sulfur and magnesium is optimized for both application windows.

7 What NPK ratio is best for asparagus?

Asparagus performs best with a higher-nitrogen fertilizer that also provides strong phosphorus and potassium. A ratio like 16-10-13 is ideal because the elevated nitrogen supports vigorous fern growth, which is how asparagus builds energy reserves for the following spring's spear production. Phosphorus maintains healthy crowns and root systems, while potassium enhances disease resistance and winter hardiness. Added sulfur and magnesium further optimize nutrient uptake and promote green, healthy fern development. Old Cobblers Farm™ Wicked Growth Asparagus Fertilizer 16-10-13 is specifically formulated with the optimal NPK ratio for asparagus.