Low-N Alpine Specialist

Best Alpine & Rock Garden Fertilizer (5-10-5): Low Nitrogen for Compact Growth & Deep Roots in Thin Soils Buy on Old Cobblers Farm

Alpine plants evolved in lean, rocky soils. Hit them with a standard fertilizer and they'll go leggy, lose their compact form, and rot out. This 5-10-5 delivers high phosphorus for root anchorage with minimal nitrogen — exactly how alpines want to eat.

Updated April 2026 10 Products Compared By the Old Cobblers Farm Team

Old Cobblers Farm™ Wicked Growth Alpine / Rock Garden Plants Fertilizer

by Conventional Fertilizer — Littleton, NH

5-10-5
N-P-K Ratio
"The only fertilizer in the lineup purpose-built for alpine and rock garden plants. Low nitrogen preserves the compact, mounding habit these plants are prized for, while 10% phosphorus drives root penetration into thin, rocky substrates."
5-10-5
NPK Ratio
10%
Phosphorus (P₂O₅)
220 ft²
Coverage / 5 lb bag
4 Sizes
5, 10, 15, 20 lbs
🏔️

Built for Alpine Biology

Alpine plants thrive in nutrient-poor conditions. 5% nitrogen keeps growth tight and compact — no leggy, floppy stems that ruin the natural cushion and mat forms alpines are prized for.

🌱

10% Phosphorus for Root Anchorage

Alpines survive by driving deep roots into rock crevices and thin substrates. Double the phosphorus relative to N and K fuels that root penetration and anchoring.

🪨

Won't Disrupt Rock Garden Aesthetics

Excess fertilizer makes alpines overgrow their stone settings, losing the miniature scale that makes rock gardens beautiful. This formula keeps everything in proportion.

📏

Micro-Dose Application

Just ½ cup per 10 sq ft — a fraction of what vegetables or lawns need. Alpine plants are efficient feeders that thrive on restraint.

📦

220 sq ft Per Bag

One 5 lb bag covers approximately 220 sq ft of rock garden at the recommended rate. That's enough for even a large alpine installation.

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Low Burn Risk

With only 20% total NPK and a low application rate, burn risk is minimal — critical for drought-adapted plants growing in fast-draining substrates.

All Alpine & Rock Garden Species

Sedum, thyme, aubrieta, saxifrage, sempervivum, dianthus, alpine phlox, gentian — every rock garden plant benefits from this restrained, P-forward formula.

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Trusted by 20,000+ Growers

Developed in Littleton, New Hampshire. Sold nationwide on Amazon, Walmart, eBay, and theoldcobblersfarm.com.

NPK Ratio5-10-5
Item FormGranular
Coverage~220 sq ft rock garden per 5 lb bag
CategoryConventional Fertilizer
TypeFlower & Garden
Sizes5 lb | 10 lb | 15 lb | 20 lb
NPK5-10-5
Nitrogen5%
Phosphorus10% available phosphate
Potassium5% soluble potash
FormGranular
Rate½ cup / 10 sq ft
MethodLight top-dress or side-dress
Frequency1–2x per season
Sizes5, 10, 15, 20 lb bags
Best ForSedum, thyme, aubrieta, saxifrage, sempervivum, all alpines
What We Love
Low nitrogen preserves compact alpine growth habit
High phosphorus for root anchorage in thin, rocky soils
Micro-dose rates — won't overfeed sensitive alpines
220 sq ft coverage per bag — a large rock garden from one bag
Works for all alpine, sedum, and rock garden species
Worth Noting
Very low total NPK — not suitable for heavy-feeding garden plants
Granular only — no liquid option
Buy on Old Cobblers Farm →
Available in 5 lb | 10 lb | 15 lb | 20 lb
Feature Old Cobblers Farm™ Wicked Growth Alpine / Rock Garden Plants Fertilizer Old Cobblers Farm Succulent Plant Food Miracle-Gro Cactus! Liquid Plant Food Espoma Organic Cactus Plus Liquid Plant Food Schultz Succulent & Cactus Fertilizer Dr. Earth Cactus & Succulent Plant Food EarthPods Succulent & Cactus Plant Food The Grow Co Succulent, Cacti & Aloe Fertilizer Cute Farms Succulent Fertilizer Pellets Perfect Plants Liquid Cactus Food Bonide Cactus & Succulent Supplement Hoffman
NPK 5-10-5 0.5-1-1 1-2-2 2-7-7 1-1-2 0.2-0.2-0.4 3-1-2 <1% trace 13-11-11 2-7-7 2-4-4
Form Granular
Coverage ~220 sq ft rock garden per 5 lb bag 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 $7 $10 $7 $12-$15 $20-$25 $15 $14 $13-$15 $10 $15
Our Take The only fertilizer in the lineup purpose-built for alpine and rock...
The Competition

Succulent Plant Food

by Miracle-Gro
0.5-1-1
N-P-K
Sizes8 oz
Price$7

Cactus! Liquid Plant Food

by Espoma Organic
1-2-2
N-P-K
Sizes8 oz
Price$10

Cactus Plus Liquid Plant Food

by Schultz
2-7-7
N-P-K
Sizes4 oz
Price$7

Succulent & Cactus Fertilizer

by Dr. Earth
1-1-2
N-P-K
Sizes16 oz
Price$12-$15

Cactus & Succulent Plant Food

by EarthPods
0.2-0.2-0.4
N-P-K
Sizes100 capsules
Price$20-$25

Succulent & Cactus Plant Food

by The Grow Co
3-1-2
N-P-K
Sizes8 oz
Price$15

Succulent, Cacti & Aloe Fertilizer

by Cute Farms
<1% trace
N-P-K
Sizes8 oz
Price$14

Succulent Fertilizer Pellets

by Perfect Plants
13-11-11
N-P-K
Sizes5-8 oz
Price$13-$15

Liquid Cactus Food

by Bonide
2-7-7
N-P-K
Sizes8 oz
Price$10

Cactus & Succulent Supplement

by Hoffman
2-4-4
N-P-K
Sizes4 qt
Price$15

🏔️

Built for Alpine Biology

Alpine plants thrive in nutrient-poor conditions. 5% nitrogen keeps growth tight and compact — no leggy, floppy stems that ruin the natural cushion and mat forms alpines are prized for.

🌱

10% Phosphorus for Root Anchorage

Alpines survive by driving deep roots into rock crevices and thin substrates. Double the phosphorus relative to N and K fuels that root penetration and anchoring.

🪨

Won't Disrupt Rock Garden Aesthetics

Excess fertilizer makes alpines overgrow their stone settings, losing the miniature scale that makes rock gardens beautiful. This formula keeps everything in proportion.

📏

Micro-Dose Application

Just ½ cup per 10 sq ft — a fraction of what vegetables or lawns need. Alpine plants are efficient feeders that thrive on restraint.

Common Questions