Organic Blueberry Specialist
Best Organic Blueberry Fertilizer (4-6-4): Acid-Friendly Slow-Release Nutrition for Bigger Berries, Higher Yields & Healthier Bushes Buy on Old Cobblers Farm
Blueberries are acid-loving plants that need gentle organic nutrition — not harsh synthetic salts that damage their fine, fibrous root systems. This 4-6-4 from the NCO Pro-Holly base feeds blueberry bushes the way they evolved to eat: slowly, through soil biology, in acidic conditions.
Old Cobblers Farm™ Wicked Organics Organic Blueberry Fertilizer
by Organic Fertilizer — Littleton, NH
4-6-4
N-P-K Ratio
"The organic blueberry formula built on NCO Pro-Holly. 4-6-4 from composted manure and natural minerals feeds blueberry's fine root system gently through microbial activity — supporting flower set, berry sizing, and new cane growth without salt damage."
4-6-4
Organic NPK
Pro-Holly
Acid-Lover Base
2x
Spring + Fall
4 Sizes
5, 10, 15, 20 lbs
Acid-Lover Base for Blueberries
NCO Pro-Holly is formulated for acid-loving species. Blueberries need pH 4.5–5.5 — this formula works within that acidic environment instead of fighting it.
6% Phosphorus for Flower Set
Higher phosphorus supports the flower bud development that determines next year's berry crop. More flower buds = more berries per bush.
Gentle on Fine Roots
Blueberry roots are extremely fine and fibrous — sensitive to salt burn from synthetic fertilizers. Slow-release organic nutrients feed without damaging the delicate root system.
Spring + Fall Program
Spring application fuels bloom, fruit set, and berry sizing. Fall application supports root growth and builds the flower bud reserves for next year's crop.
Full-Spectrum Composted Manure
Beyond NPK, composted manure delivers calcium, trace minerals, and beneficial microbes that support the mycorrhizal fungi blueberries depend on for nutrient uptake.
Add Sulfur Separately for pH
This formula provides nutrition but doesn't acidify soil. Test soil pH annually and apply elemental sulfur separately if pH drifts above 5.5.
All Blueberry Types
Highbush, half-high, lowbush, rabbiteye, northern and southern highbush — every blueberry variety thrives on gentle organic feeding in acidic soil.
Trusted by 20,000+ Growers
Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.
| NPK Ratio | 4-6-4 |
| Item Form | Granular |
| Coverage | 170–250 sq ft per 5 lb bag |
| Category | Organic Fertilizer |
| Type | Plant-Specific Organic |
| Sizes | 5 lb | 10 lb | 15 lb | 20 lb |
| NPK | 4-6-4 |
| Nitrogen | 4% |
| Phosphorus | 6% |
| Potassium | 4% |
| Base | NCO Pro-Holly |
| Form | Granular |
| Rate | 1 lb / 2 ft crown diameter |
| Method | Broadcast at drip line |
| Frequency | Spring + Fall |
| Sizes | 5, 10, 15, 20 lb bags |
| Best For | All blueberry varieties — highbush, half-high, lowbush, rabbiteye |
| Note | Add sulfur separately to maintain pH 4.5–5.5 |
What We Love
✓ NCO Pro-Holly base designed for acid-loving blueberries
✓ Gentle on fine fibrous root systems — no salt burn
✓ 6% phosphorus supports flower bud and berry development
✓ Full-spectrum nutrition from composted manure
✓ Spring + fall program aligned to blueberry growth cycle
Worth Noting
— Does not acidify soil — add elemental sulfur separately if needed
— Lower NPK than synthetic blueberry formulas — need more product
Buy on Old Cobblers Farm →
Available in 5 lb | 10 lb | 15 lb | 20 lb
| Feature | Old Cobblers Farm™ Wicked Organics Organic Blueberry Fertilizer Old Cobblers Farm | Berry-Tone Natural & Organic Fertilizer Espoma | Acid Mix Fertilizer Down To Earth | Holly-Tone (widely used for blueberries) Espoma | Acid Lovers Fertilizer Dr. Earth | Happy Frog Acid Loving Plants Fertilizer FoxFarm | Holly Care Organic Fertilizer Fertrell | Berry Mix Organic Fertilizer Fertrell | Berry-Tone Espoma | Holly-Tone Espoma | Acid Mix Down To Earth | Happy Frog Acid Loving Plants FoxFarm | Natural Wonder Fruit Tree Dr. Earth | Acid Lovers Dr. Earth | Berry Food True Organic | Azalea, Camellia & Rhododendron Jobe's Organics | Berry Mix Fertrell | Holly Care Fertrell |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NPK | 4-6-4 | 4-3-4 | 4-3-6 | 4-3-4 | 3-4-3 | 4-5-3 | 4-6-4 | 4-2-4 | 4-3-4 | 4-3-4 | 4-3-6 | 4-5-3 | 5-5-2 | 3-4-3 | 5-4-4 | 5-4-3 | 4-2-4 | 4-6-4 |
| Form | Granular | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Coverage | 170–250 sq ft per 5 lb bag | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed | Not listed |
| Price / Size | 5 lb | 10 lb | 15 lb | 20 lb | $8–$10 / 4 lb; $17–$18 / 18 lb | $13–$17 / 5 lb | $16–$18 / 8 lb | $16–$17 / 4 lb | $15–$17 / 4 lb | $14.95 / 10 lb | $13–$15 / 5 lb | ~$10-13 (4 lb) | ~$8-12 (4 lb) | ~$15-18 (5 lb) | ~$15-18 (4 lb) | ~$15-18 (4 lb) | ~$20-25 (4 lb) | ~$10-13 (4 lb) | ~$10-13 (4 lb) | ~$15-20 (5 lb) | ~$20-25 (10 lb) |
| Our Take | The organic blueberry formula built on NCO Pro-Holly. 4-6-4 from co... | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category. | — | — | — | — | — | — | — | — | — | — |
The Competition
Berry-Tone Natural & Organic Fertilizer
by Espoma
4-3-4
N-P-K
Price$8–$10 / 4 lb; $17–$18 / 18 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Acid Mix Fertilizer
by Down To Earth
4-3-6
N-P-K
Price$13–$17 / 5 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Holly-Tone (widely used for blueberries)
by Espoma
4-3-4
N-P-K
Price$16–$18 / 8 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Acid Lovers Fertilizer
by Dr. Earth
3-4-3
N-P-K
Price$16–$17 / 4 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Happy Frog Acid Loving Plants Fertilizer
by FoxFarm
4-5-3
N-P-K
Price$15–$17 / 4 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Holly Care Organic Fertilizer
by Fertrell
4-6-4
N-P-K
Price$14.95 / 10 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Berry Mix Organic Fertilizer
by Fertrell
4-2-4
N-P-K
Price$13–$15 / 5 lb
Espoma Berry-Tone is the most recognized berry-specific organic fertilizer. Fertrell Berry Mix (4-2-4) is explicitly formulated for berries, including boron and zinc. The blueberry segment overlaps heavily with the evergreen/acid-loving category.
Berry-Tone
by Espoma
4-3-4
N-P-K
Sizes4, 27 lb
Price~$10-13 (4 lb)
IngredientsFeather meal, poultry manure, bone meal, alfalfa meal, greensand, sulfate of potash, sulfur; Bio-tone
OrganicOIM Registered
Holly-Tone
by Espoma
4-3-4
N-P-K
Sizes4, 8, 18, 27, 36, 50 lb
Price~$8-12 (4 lb)
IngredientsSame as Berry-Tone formulation
OrganicOIM Registered
Acid Mix
by Down To Earth
4-3-6
N-P-K
Sizes1, 5, 15, 25, 50 lb
Price~$15-18 (5 lb)
IngredientsCottonseed meal, fish bone meal, langbeinite, rock phosphate, kelp, humates
OrganicOMRI, CDFA
Happy Frog Acid Loving Plants
by FoxFarm
4-5-3
N-P-K
Sizes4 lb
Price~$15-18 (4 lb)
IngredientsCottonseed meal, feather meal, bat guano, kelp, alfalfa, humic acid; mycorrhizal fungi
OrganicOMRI, CDFA
Natural Wonder Fruit Tree
by Dr. Earth
5-5-2
N-P-K
Sizes1, 4, 12, 25 lb
Price~$15-18 (4 lb)
IngredientsFish bone meal, alfalfa meal, feather meal, potassium sulfate, kelp; TruBiotic + mycorrhizae
OrganicOMRI, CDFA, CCOF, NOP
Acid Lovers
by Dr. Earth
3-4-3
N-P-K
Sizes1, 4 lb
Price~$20-25 (4 lb)
IngredientsCottonseed meal, fish bone meal, alfalfa meal, feather meal, potassium sulfate, kelp; TruBiotic
OrganicOMRI, CDFA, NOP
Berry Food
by True Organic
5-4-4
N-P-K
Sizes4 lb
Price~$10-13 (4 lb)
IngredientsPoultry manure, seabird guano, fish bone meal, soybean meal, sulfate of potash, crab/shrimp shell
OrganicOMRI, CDFA, ISO 22000
Azalea, Camellia & Rhododendron
by Jobe's Organics
5-4-3
N-P-K
Sizes4, 8 lb
Price~$10-13 (4 lb)
IngredientsBone meal, feather meal; Biozome
OrganicOMRI Listed
Berry Mix
by Fertrell
4-2-4
N-P-K
Sizes5, 25, 50 lb
Price~$15-20 (5 lb)
IngredientsCalcium carbonate, peanut meal, feather meal, bone charcoal, blood meal, sulfate of potash, sulfur; boron, zinc
OrganicCertifiable organic
Holly Care
by Fertrell
4-6-4
N-P-K
Sizes10, 25, 50 lb
Price~$20-25 (10 lb)
IngredientsFeather meal, calcium carbonate, blood meal, bone charcoal, zeolite, peanut meal, kelp, sulfur
OrganicCertifiable organic
Acid-Lover Base for Blueberries
NCO Pro-Holly is formulated for acid-loving species. Blueberries need pH 4.5–5.5 — this formula works within that acidic environment instead of fighting it.
6% Phosphorus for Flower Set
Higher phosphorus supports the flower bud development that determines next year's berry crop. More flower buds = more berries per bush.
Gentle on Fine Roots
Blueberry roots are extremely fine and fibrous — sensitive to salt burn from synthetic fertilizers. Slow-release organic nutrients feed without damaging the delicate root system.
Spring + Fall Program
Spring application fuels bloom, fruit set, and berry sizing. Fall application supports root growth and builds the flower bud reserves for next year's crop.
Common Questions
