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Old Cobblers Farm™ Wicked Growth 8-0-16 Fertilizer – Zero Phosphorus
Zero phosphorus, high potassium 8-0-16 fertilizer for orchards, gardens & lawns. Application rates & tips from Old Cobblers Farm.
Growing Guides & Fertilizer Education
This 8-0-16 formula is the general-purpose version of Old Cobblers Farm's Apple Tree Fertilizer—both share the same Green Mountain Fertilizer formulation. The three-ingredient blend (urea, muriate of potash, silicon dioxide with micronutrients) provides exactly what established plantings need without anything they don't.
The zero-phosphorus design reflects responsible nutrient management. Phosphorus binds tightly to soil particles and accumulates year after year. Many established gardens have soil P well above optimal, and continued application provides no benefit while increasing waterway pollution risk. The 8% nitrogen provides maintenance-level growth support, and the 16% potassium replenishes the nutrient crops export in the largest quantities through harvest.
NPK
8-0-16
Type
Non-Organic
Derived From
Urea, Potassium Chloride (Muriate of Potash), Silicon Dioxide. Includes micronutrients.
Best For
Fruit Trees|Established Orchards|Grapes|Berry Patches|Established Gardens|Hay Fields|Pastures|Lawns
Brand
Wicked Growth
NPK Breakdown
N
8
Provides 8% nitrogen (from urea) for steady leaf growth and shoot extension without excessive vegetative vigor that reduces fruit quality or invites disease
P
0
N/A — Contains no phosphorus. Designed for established plantings where soil phosphorus is already adequate. Adding unnecessary phosphorus can interfere with zinc and iron uptake.
K
16
Supplies a strong 16% potassium (from muriate of potash) to improve fruit size, color, sugar content, firmness, winter hardiness, and overall plant vigor
What Is It ?
The 8-0-16 fertilizer is a zero-phosphorus, high-potassium granular blend designed for established gardens, orchards, and landscapes where soil phosphorus is already adequate but potassium needs replenishment. In many cultivated soils, years of fertilizer and compost applications have built phosphorus to adequate or excessive levels, while potassium declines from continuous crop removal. Applying balanced NPK in these situations wastes money on unnecessary phosphorus and can create environmental runoff problems. The 8-0-16 formula delivers only what your soil actually needs: a maintenance dose of nitrogen (8%) for steady growth and a strong dose of potassium (16%) for fruit quality, disease resistance, drought tolerance, and winter hardiness. Micronutrients are included for complete nutrition. This is the same formulation as Old Cobblers Farm™ Apple Tree Fertilizer. Manufactured by Green Mountain Fertilizer in Milton, Vermont.
When To Apply ?
Apply in early spring before active growth. For orchards, broadcast under the tree canopy from 1 foot out to the drip line. For garden beds, spread evenly and lightly incorporate. For hay fields and pastures, broadcast at 200-400 lbs per acre in early spring. For lawns, use a calibrated spreader at 3-5 lbs per 1,000 sq ft. Apply using the same rates and methods as Old Cobblers Farm™ Apple Tree Fertilizer.
How to Apply ?
1.
Soil Test
Confirm with a soil test that phosphorus is adequate but potassium needs supplementation.
2.
Garden Rate
Broadcast 0.5–1 lb per 100 sq ft in early spring for gardens and established beds.
3.
Fruit Tree Rate
For fruit trees, apply 0.5–1 lb per inch of trunk diameter under the canopy from 1 foot out to the drip line.
4.
Lawn Rate
For lawns, apply 3–5 lbs per 1,000 sq ft with a calibrated spreader for even distribution.
5.
Water In
Water thoroughly after application to dissolve granules and move nutrients into the root zone.
6.
Optional Side-Dress
Optional mid-season side-dress for heavy-producing crops at half the initial rate to sustain fruiting.
7
Fruit Tree Rate
For fruit trees, apply 0.5–1 lb per inch of trunk diameter under the canopy from 1 foot out to the drip line.
How To Store
Wear protective gloves and eye protection during handling. Avoid breathing dust. Wash hands thoroughly after handling. Store in a cool, dry, well-ventilated area. 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 8-0-16 fertilizer used for?
8-0-16 fertilizer is a zero-phosphorus formula with elevated nitrogen and potassium designed for established plantings in soils that already have sufficient phosphorus. The higher nitrogen (8%) compared to 6-0-16 provides more vigorous foliage growth, while the high potassium (16%) strengthens plants against environmental stress. It is commonly used for lawn maintenance, fruit tree care, and agricultural crops where phosphorus is not needed but nitrogen and potassium are. Old Cobblers Farm™ Wicked Growth 8-0-16 Fertilizer delivers targeted nutrition for healthy, resilient plants without contributing to phosphorus buildup in the soil.
2.
What is the difference between 6-0-16 and 8-0-16 fertilizer?
Both are zero-phosphorus formulas with high potassium, but 8-0-16 provides more nitrogen (8% vs 6%). Choose 8-0-16 when plants need stronger vegetative growth support — for example, actively growing lawns, fruit trees during canopy development, or crops in their vegetative stage. Choose 6-0-16 when you want minimal nitrogen input with maximum potassium, such as for stress conditioning or fall hardening. Both are excellent choices for established plantings in phosphorus-rich soils. Old Cobblers Farm™ Wicked Growth offers both options so you can match the formula to your specific growing conditions.
3.
Is 8-0-16 good for apple trees?
Yes, 8-0-16 is an excellent choice for apple trees, particularly mature trees in soils with adequate phosphorus. The nitrogen promotes healthy leaf growth and canopy density, which drives photosynthesis and fruit production. The high potassium directly improves fruit size, sweetness, color, and storage quality. Apply 1–2 pounds per inch of trunk diameter in early spring before bud break, spreading evenly under the drip line. Old Cobblers Farm™ Wicked Growth Apple Tree Fertilizer uses this same 8-0-16 ratio, delivering the targeted nutrition apple trees need for healthier growth and bigger, sweeter harvests.
4.
Can I use zero-phosphorus fertilizer on vegetables?
Yes, zero-phosphorus fertilizers like 8-0-16 work well on established vegetable gardens where soil tests show phosphorus levels are already adequate or high. Many gardens that have received regular fertilization or compost applications for several years accumulate excess phosphorus. In these situations, continuing to add phosphorus can actually inhibit nutrient uptake. Switching to a zero-phosphorus formula keeps your soil balanced and your plants healthier. Old Cobblers Farm™ Wicked Growth 8-0-16 Fertilizer provides the nitrogen and potassium vegetables need without adding unnecessary phosphorus.
5.
When should I use a high potassium fertilizer?
Use high potassium fertilizers when plants are fruiting, under environmental stress, or heading into dormancy. Potassium improves fruit quality, strengthens cell walls, regulates water within the plant, and enhances disease and cold resistance. It is especially valuable during mid-to-late season when crops are setting and ripening fruit, and in fall when lawns and perennials need to build winter hardiness. Soil tests showing low potassium levels are another clear signal. Old Cobblers Farm™ Wicked Growth 8-0-16 Fertilizer delivers a strong dose of potassium (16%) to support plant strength exactly when it matters most.
6.
Does 8-0-16 fertilizer work on lawns?
Yes, 8-0-16 is an effective lawn fertilizer for established turf in phosphorus-adequate soils. The 8% nitrogen promotes thick, green grass, while the 16% potassium strengthens root systems and improves tolerance to drought, heat, cold, and traffic. It is especially well-suited for summer and fall applications when lawns need resilience more than rapid growth. Many municipalities restrict phosphorus use in lawn fertilizers due to water quality concerns, making zero-phosphorus formulas like 8-0-16 both practical and environmentally responsible. Old Cobblers Farm™ Wicked Growth 8-0-16 Fertilizer keeps lawns strong and green without excess phosphorus.
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How much potassium do fruit trees need?
Fruit trees generally need 0.5–1.5 pounds of actual potassium (K₂O) per tree per year, depending on size and crop load. Trees under heavy fruit production require more potassium because each fruit removes significant amounts during development. Signs of potassium deficiency include leaf edge browning, small fruit, poor color development, and reduced winter hardiness. Soil testing is the best way to determine exact needs. With 16% potassium, 8-0-16 fertilizer provides a concentrated dose per application. Old Cobblers Farm™ Wicked Growth 8-0-16 Fertilizer delivers the potassium fruit trees need for bigger, sweeter, and longer-storing harvests.