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Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer
Blueberry-specific fertilizer with ammonium sulfate for acid-loving plants. Lowers pH, provides ammonium nitrogen. Rates & tips from Old Cobblers Farm.
Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer
Wicked Growth Blueberry Mix is a conventional granular fertilizer that combines the balanced 10-10-10 base formula (Urea, Diammonium Phosphate, Potassium Chloride, Silicon Dioxide) with Ammonium Sulfate (21-0-0) to create a blueberry-optimized blend. The addition of ammonium sulfate shifts both the nitrogen form and the soil chemistry in exactly the direction blueberries need.
Blueberries are members of the Ericaceae family and have evolved in naturally acidic forest soils. Their root systems lack the root hairs that most plants use for nutrient absorption — instead, they rely on mycorrhizal fungi that function best in acidic conditions. When soil pH rises above 5.5, these mycorrhizal associations weaken, and critical micronutrients like iron and manganese become chemically unavailable, leading to chlorosis (yellowing between leaf veins), stunted growth, and poor fruiting.
The ammonium sulfate in this blend addresses this through two mechanisms: the ammonium nitrogen (NH4+) acidifies the soil as it undergoes nitrification (conversion to nitrate by soil bacteria releases hydrogen ions), and the sulfate sulfur provides additional acidifying potential. Together, they help maintain the pH 4.5-5.5 range where blueberries perform best. Unlike urea-based nitrogen (which blueberries can use but which does not acidify soil as effectively), ammonium sulfate is the gold-standard nitrogen source for Vaccinium species.
NPK
10-10-10
Type
Non-Organic
Derived From
Urea, Diammonium Phosphate (DAP), Potassium Chloride (Muriate of Potash), Silicon Dioxide, enhanced with Ammonium Sulfate (21-0-0) for acid-loving plant nutrition. The ammonium sulfate provides 24% sulfur as sulfate.
Best For
Blueberries|Cranberries|Lingonberries|Huckleberries|Azaleas|Rhododendrons|Camellias|Hydrangeas (blue)
Brand
Wicked Growth
NPK Breakdown
N
10
Provides 10% nitrogen from urea, diammonium phosphate, and ammonium sulfate. The ammonium sulfate component delivers nitrogen in the ammonium form (NH4+) that blueberry roots absorb directly, and provides 24% sulfur that gradually acidifies the soil toward the low pH range blueberries demand.
P
10
Delivers 10% phosphorus from diammonium phosphate (DAP) to support root development, flower bud formation, and fruit set in blueberry bushes.
K
10
Supplies 10% potassium from muriate of potash to improve berry size, sweetness, firmness, disease resistance, and winter hardiness.
What Is It ?
Blueberry Mix Fertilizer is a high-performance conventional blend built on the proven 10-10-10 base formula and enhanced with ammonium sulfate specifically for the unique nutritional demands of blueberry bushes and other acid-loving plants. Blueberries have two critical requirements that most general-purpose fertilizers fail to address: they strongly prefer ammonium-form nitrogen over nitrate nitrogen, and they need acidic soil conditions (pH 4.5-5.5) to access essential micronutrients like iron and manganese. This enhanced formula solves both problems in a single application. The ammonium sulfate component delivers nitrogen as ammonium ions (NH4+) that blueberry roots absorb directly without the conversion step that nitrate nitrogen requires, while the sulfate component provides sulfur that gradually lowers soil pH toward the acidic range blueberries thrive in. Combined with the balanced NPK nutrition from the 10-10-10 base — phosphorus for root development and flower bud formation, potassium for berry quality and winter hardiness — this formula delivers complete, targeted nutrition for productive blueberry bushes. Old Cobblers Farm™ Wicked Growth Blueberry Mix is the conventional grower's solution for maximum berry production from established and newly planted bushes alike.
When To Apply ?
For established blueberry bushes (3+ years), apply 1-2 cups per bush scattered evenly from 6 inches from the stem to the drip line in early spring when buds begin to swell. A second application immediately after harvest (typically July-August) fuels the new shoot growth that will produce next year's fruit buds. For newly planted bushes in their first year, use half rates (0.5 cup) and wait 4-6 weeks after planting before the first application to allow roots to establish. For commercial operations, apply 300-500 lbs per acre split between spring and post-harvest applications. Always water in thoroughly after application — ammonium sulfate can cause surface burn if left dry near stems or on mulch. If blueberries show signs of iron chlorosis (yellowing between green veins), the acidifying effect of this fertilizer will help make iron more available over time.
How to Apply ?
1.
Soil pH Test
Test soil pH before applying — target 4.5–5.5 for blueberries. If pH is above 5.5, add sulfur amendments before fertilizing.
2.
Measure Rate
Measure fertilizer based on bush size and age. Larger, mature bushes need more than young plantings.
3.
Ring Application
Spread evenly in a ring around the bush base, starting 6 inches from the stem out to the drip line.
4.
Avoid Stem Contact
Do not pile fertilizer against stems or crowns. Blueberry roots are shallow and sensitive to burn.
5.
Water In
Water thoroughly after application to move nutrients into the shallow root zone.
6.
Timing
Apply first dose in early spring at bud break, second application after harvest ends to support next year's buds.
7
Ring Application
Spread evenly in a ring around the bush base, starting 6 inches from the stem out to the drip line.
How To Store
Wear gloves and eye protection during handling. Avoid inhaling dust during application. Store in a cool, dry location in a sealed container — ammonium sulfate is hygroscopic and will clump if exposed to humidity. Keep away from lime, urea, and alkaline materials. Keep away from water sources, ponds, and storm drains. Safe around pets and children once watered into soil.
FAQs
1.
Is 10-10-10 fertilizer good for blueberries?
Yes, 10-10-10 can be used on blueberries as part of a comprehensive care program. The balanced nitrogen supports bush growth and leaf development, phosphorus promotes root health and flower bud formation, and potassium improves berry quality and winter hardiness. However, blueberries also require acidic soil (pH 4.5–5.5) for optimal nutrient uptake, so pairing a balanced fertilizer with soil acidifiers like elemental sulfur or ammonium sulfate is important. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer 10-10-10 is formulated specifically for blueberry bushes, delivering the complete nutrition they need for productive harvests.
2.
What is the best fertilizer for blueberry bushes?
The best blueberry fertilizer provides balanced NPK nutrition while supporting the acidic soil conditions blueberries require. A 10-10-10 formula delivers equal parts nitrogen for bush growth, phosphorus for root development and flower formation, and potassium for berry size, flavor, and disease resistance. For established bushes, pairing this with ammonium sulfate or elemental sulfur helps maintain the low pH blueberries need. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer 10-10-10 is designed to support healthy growth and abundant berry production in both newly planted and established blueberry bushes.
3.
When should I fertilize blueberry bushes?
Fertilize blueberries in early spring before new growth begins, typically late March to early April. A second application can be made after harvest in mid-summer to support flower bud formation for next year's crop. Avoid fertilizing in late fall or winter when bushes are dormant. For newly planted blueberries, wait 4–6 weeks after planting before the first application and use a reduced rate. Always water thoroughly after applying fertilizer. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer 10-10-10 provides the seasonal nutrition blueberries need for consistent annual production.
4.
What NPK ratio is best for blueberries?
Blueberries respond well to balanced NPK ratios like 10-10-10, which supports all aspects of bush growth — foliage, roots, and fruit. Some growers prefer higher-nitrogen formulas using ammonium-based nitrogen sources (like ammonium sulfate) that also help maintain acidic soil conditions. The ideal approach depends on your soil test results. If soil pH and phosphorus are adequate, a nitrogen-focused formula may be best. If the soil needs comprehensive nutrition, a balanced 10-10-10 is the practical choice. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer is optimized specifically for blueberry nutrition.
5.
How much fertilizer do blueberry bushes need?
For established blueberry bushes, apply 1–2 cups of 10-10-10 fertilizer per bush, spreading evenly around the drip line. Young bushes (1–2 years) need only ½–1 cup. Lightly incorporate the fertilizer into the top inch of soil and water thoroughly. Avoid placing fertilizer directly against the trunk. Blueberry feeder roots are shallow and extend beyond the branch tips, so broadcast the fertilizer over this entire area. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer 10-10-10 is easy to measure and apply for consistent blueberry nutrition.
6.
Do blueberries need acidic soil?
Yes, blueberries require acidic soil with a pH between 4.5 and 5.5 for optimal growth and nutrient uptake. In alkaline or neutral soils, blueberries cannot efficiently absorb iron, manganese, and other essential nutrients, leading to yellowing leaves (chlorosis), poor growth, and reduced fruit production. Test your soil pH before planting and amend with elemental sulfur or aluminum sulfate if needed. Maintaining acidity is an ongoing process. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer works best when soil pH is within the proper range — consider pairing it with Wicked Growth Ammonium Sulfate 21-0-0 for pH maintenance.
7
Can I use blueberry fertilizer on other acid-loving plants?
Yes, blueberry fertilizer works well on other acid-loving plants including azaleas, rhododendrons, gardenias, hydrangeas, hollies, mountain laurels, and raspberries. These plants share similar nutritional needs and preference for acidic soil conditions. The balanced 10-10-10 NPK ratio supports growth, root health, and flowering across all acid-loving species. Old Cobblers Farm™ Wicked Growth Blueberry Mix Fertilizer 10-10-10 is versatile enough for mixed acid-loving plantings while providing the specific nutrition blueberries demand for top production.