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

Updated April 2026 By the Old Cobblers Farm Team

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

by Wicked Growth — 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.

💧

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.

🇺🇸

Trusted by 20,000+ Growers

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

NPK Ratio5-10-5
Derived FromUrea, Diammonium Phosphate, Muriate of Potash, Silicon Dioxide
Item FormGranular
Release SpeedModerate-release
Application Rate½ cup / 10 sq ft | ¼–1 cup / plant cluster
MethodLight top-dress or side-dress around plant clusters
Frequency1–2x per season (spring + mid-summer)
Sizes5 lb | 10 lb | 15 lb | 20 lb
SupportsSedum, thyme, aubrieta, saxifrage, sempervivum, dianthus, armeria, alpine phlox, gentian, edelweiss, hens-and-chicks
SetupsRock gardens, alpine beds, crevice gardens, scree beds, stone walls, troughs
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 Succulent Plant Food Cactus! Liquid Plant Food Cactus Plus Liquid Plant Food Succulent & Cactus Fertilizer Cactus & Succulent Plant Food Succulent & Cactus Plant Food Succulent, Cacti & Aloe Fertilizer Succulent Fertilizer Pellets Liquid Cactus Food Cactus & Succulent Supplement
NPK 5-10-5 0.5-1-1 1-2-2002 2-7-2007 1-1-2002 0.2-0.2-0.4 3-1-2002 <1% trace 13-11-11 2-7-2007 2-4-2004
Phosphorus 10.0% 1.0% 2.0% 7.0% 1.0% 0.2% 1.0% 0.0% 11.0% 7.0% 4.0%
Potassium 5.0% 1.0% 2.0% 7.0% 2.0% 0.4% 2.0% 0.0% 11.0% 7.0% 4.0%
Form Granular
Sizes 5 lb | 10 lb | 15 lb | 20 lb 8 oz 8 oz 4 oz 16 oz 100 capsules 8 oz 8 oz 5-8 oz 8 oz 4 qt
Release Speed Moderate-release
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
1-2-2002
N-P-K
Sizes8 oz
Price$10

Cactus Plus Liquid Plant Food

by Schultz
2-7-2007
N-P-K
Sizes4 oz
Price$7

Succulent & Cactus Fertilizer

by Dr. Earth
1-1-2002
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
3-1-2002
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
2-7-2007
N-P-K
Sizes8 oz
Price$10

Cactus & Succulent Supplement

by Hoffman
2-4-2004
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