Comparison: Best Black Gold Organic Earthworm Castings (Updated | Nov 11th)
If you’re on the hunt for the **best black gold organic earthworm castings**, you’re not alone—gardeners everywhere are raving about this natural powerhouse. But with so many options out there, how do you know which one truly delivers? We’ve dug deep—literally—to compare top contenders, evaluating nutrient content, sourcing, and real garden results. Whether you’re growing tomatoes, flowers, or lush greens, the right castings can make all the difference. Let’s break down what sets the best apart and help you choose the ultimate soil booster for a thriving, healthy garden.
- Best for nutrient powerhouse: Uncle Jim’s Worm Farm Black Gold Worm Castings Compost Fertilizer for Garden Soil | Red Wriggler Earthworm Casting Organic Fertilizer for Plants | Nutrient Rich Fertilizer Solutions | 4 lbs
- Best for peat-free organic: Organic Earthworm Castings by The Urban Worm Company – OMRI-Listed Peat-Free Black Gold to Improve Soil Fertility (15 Pounds)
- Best for us-made peat-free: Organic Earthworm Castings by The Urban Worm Company – OMRI-Listed Peat-Free Black Gold to Improve Soil Fertility (30
- Best for bulk garden blend: Black Gold 1490302 8 QT P 8 Quart Earthworm Castings Blend
- Best for family organic premium: Brut Organic Worm Castings for Plants 12 LB – Natural Nutrients
- Best for pure odorless castings: Wiggle Worm 100% Pure Organic Worm Castings – Organic Fertilizer for Houseplants
- Best for large-scale pure: Wiggle Worm 100% Pure Organic Worm Castings Fertilizer
- Best for bulk family organic: Brut Organic Worm Castings for Plants 30 LB – Natural Nutrients
- Best for eco safe fertilizer: Renew Organics 100% Organic Worm Castings (3lbs) – Earthworm Fertilizer & Soil Amendment for Indoor Outdoor Plants Gardens Vegetables – Odorless Non-Burning Pet Safe
- Best for egg-enhanced soil: WIGGLE WORM Castings Plus Worm Egg Material
Product Comparison: Best Black Gold Organic Earthworm Castings
Uncle Jim’s Worm Farm Black Gold Worm Castings Compost Fertilizer for Garden Soil | Red Wriggler Earthworm Casting Organic Fertilizer for Plants | Nutrient Rich Fertilizer Solutions | 4 lbs
- Worm Castings Organic Fertilizer: Our worms are raised in worm beds that are decades old and work all layers of the compost, not just the top few inches, creating a wholly better compost. The worm casting mix is full of nutrients and aerated by the earthworm colony, providing the best possible growing base for plants.
- Black Gold Worm Castings: Using live earthworm castings for gardening and plant growing purposes can benefit any garden or farm soil. The food scraps and waste the worms consume in the compost bin gets digested and transformed into some of the most nutritious earth material that lawns and gardens could grow in: worm castings!
- Organic Worm Castings: The worm castings produced by our worms are 7 times richer in phosphates, 5 times richer in nitrogen, and 11 times richer in potash than average lawn soil. The ample supply of nutrients provided by each worm composter helps your garden to grow healthier plants and this valuable substance is all a result of your trash!
- Composting Worms Help the Earth: By feeding food scraps to compost worms instead of throwing them away, we all help to recycle nutrients and keep less trash in landfills. Using worm castings also reduces the need for harmful earth-destroying chemicals, instead relying on safe, organic compost production.
- Uncle Jim’s Worm Farm: We’ve been in business for over 50 years, using over 40 acres of land, the largest worm farm in the US! We’re a “Down to Earth” company and handle the whole process of growing and farming composting worms for the market from start to finish. All of our worms are proudly raised in the USA. Here at Uncle Jim’s, we really know worms!
Organic Earthworm Castings by The Urban Worm Company – OMRI-Listed Peat-Free Black Gold to Improve Soil Fertility (15 Pounds)
- 100% Natural and Organic: Urban Worm Company Worm Castings are made from carefully sourced, peat-free ingredients, making them an excellent choice for organic gardening.
- Boosts Plant Growth: Worm castings feature plant-available nutrients including nitrogen, phosphorus, and potassium, which help promote healthy plant growth and increase plant yield.
- Improves Soil Health: Worm castings contain lively organisms that help improve soil structure, nutrient cycling, and water retention, making them an excellent amendment for improving soil health.
- Easy to Use: Urban Worm Company Worm Castings are easy to apply to your garden. Simply sprinkle them around your plants or mix them into the soil at the base of your plants.
- Made in the USA: Urban Worm Company Worm Castings are proudly made in the USA using peat-free feedstock.
Organic Earthworm Castings by The Urban Worm Company – OMRI-Listed Peat-Free Black Gold to Improve Soil Fertility (30, Pounds)
- 100% Natural and Organic: Urban Worm Company Worm Castings are made from carefully sourced, peat-free ingredients, making them an excellent choice for organic gardening.
- Boosts Plant Growth: Worm castings are rich in nutrients, including nitrogen, phosphorus, and potassium, which help promote healthy plant growth and increase plant yield.
- Improves Soil Health: Worm castings contain beneficial organisms that help improve soil structure, nutrient cycling, and water retention, making them an excellent amendment for improving soil health.
- Easy to Use: Urban Worm Company Worm Castings are easy to apply to your garden. Simply sprinkle them around your plants or mix them into the soil at the base of your plants.
- Made in the USA: Urban Worm Company Worm Castings are proudly made in the USA using peat-free feedstock.
Black Gold 1490302 8 QT P 8 Quart Earthworm Castings Blend
Brut Organic Worm Castings for Plants 12 LB – Natural Nutrients, Fertility Builder, Plant Food for Potting Soil and Garden Soil – Indoor and Outdoor Use
- SUPERCHARGE YOUR GARDEN: Elevate your plants’ growth with premium organic Brut Worm Castings. Our certified organic formula guarantees optimal nutrition for your indoor and outdoor plants.
- PURE ORGANIC GOODNESS: Made with certified organic ingredients, our worm castings are raised indoors in containers, ensuring unparalleled purity and effectiveness for your plants’ health.
- LUSH & VIBRANT PLANTS: Watch your plants thrive with mineral-rich Brut Worm Castings. Experience lush greenery, vibrant blooms, and bountiful harvests—naturally nourishing your plants from root to leaf.
- BORN FROM FAMILY CARE: As a family-owned business, we take pride in offering the finest organic castings. Every batch is carefully crafted to nurture your plants as if they were our own.
- CERTIFIED ORGANIC: Our castings are OMRI and CDFA listed, representing true organic excellence and bringing the power of nature’s nutrients directly to your plants’ roots. Eco sustainable resorce for your gardening enjoyment!
Wiggle Worm 100% Pure Organic Worm Castings – Organic Fertilizer for Houseplants, Vegetables, and More, 15-Pounds
- Pure Earthworm Castings – WIGGLE WORM Worm Castings is pure castings, not vermicompost, and is one of the only castings products to be recognized as a fertilizer. This is because of our special manufacturing and harvesting process. It’s not uneaten worm bedding with some worm castings, so it’s pure, nutrient-rich, and mineral-dense
- Improves Soil Structure – WIGGLE WORM Pure Worm Castings contain tiny, football-shaped particles to help improve plant soil aeration. Our soil supplement also helps improve the root’s water retention capacity
- Indoor and Outdoor Use – WIGGLE WORM Pure Worm Castings are great for both outdoor and indoor gardens because it’s odorless and non-toxic. Our worm castings are an excellent organic fertilizer for vegetables, flowers, houseplants, and more
- Easy-to-Use – A little goes a long way with WIGGLE WORM, so a handful or half a cup is all you need. Apply our worm castings for gardening into the soil above the root zone three times a year or to the hole during transplant or seeding
- OMRI listed for organic use – The simple fact is that Earthworm Castings were created by nature for the purpose of promoting optimum plant growth and everything required to provide it, is found in them
Wiggle Worm 100% Pure Organic Worm Castings Fertilizer, 30-Pounds – Improves Soil Fertility and Aeration for Houseplants, Vegetables, Gardens, and More – OMRI-Listed and Mineral-Dense
- Pure Earthworm Castings – WIGGLE WORM Worm Castings is pure castings, not vermicompost, and is one of the only castings products to be recognized as a fertilizer. This is because of our special manufacturing and harvesting process. It’s not uneaten worm bedding with some worm castings, so it’s pure, nutrient-rich, and mineral-dense
- Improves Soil Structure – WIGGLE WORM Pure Worm Castings contain tiny, football-shaped particles to help improve plant soil aeration. Our soil supplement also helps improve the root’s water retention capacity
- Indoor and Outdoor Use – WIGGLE WORM Pure Worm Castings are great for both outdoor and indoor gardens because it’s odorless and non-toxic. Our worm castings are an excellent organic fertilizer for vegetables, flowers, houseplants, and more
- Easy-to-Use – A little goes a long way with WIGGLE WORM, so a handful or half a cup is all you need. Apply our worm castings for gardening into the soil above the root zone three times a year or to the hole during transplant or seeding
- OMRI listed for organic use – The simple fact is that Earthworm Castings were created by nature for the purpose of promoting optimum plant growth and everything required to provide it, is found in them
Brut Organic Worm Castings for Plants 30 LB – Natural Nutrients, Fertility Builder, Plant Food for Potting Soil and Garden Soil – Indoor and Outdoor Use
- SUPERCHARGE YOUR GARDEN: Elevate your plants’ growth with premium organic Brut Worm Castings. Our certified organic formula guarantees optimal nutrition for your indoor and outdoor plants.
- PURE ORGANIC GOODNESS: Made with certified organic ingredients, our worm castings are raised indoors in containers, ensuring unparalleled purity and effectiveness for your plants’ health.
- LUSH & VIBRANT PLANTS: Watch your plants thrive with mineral-rich Brut Worm Castings. Experience lush greenery, vibrant blooms, and bountiful harvests—naturally nourishing your plants from root to leaf.
- BORN FROM FAMILY CARE: As a family-owned business, we take pride in offering the finest organic castings. Every batch is carefully crafted to nurture your plants as if they were our own.
- CERTIFIED ORGANIC: Our castings are OMRI and CDFA listed, representing true organic excellence and bringing the power of nature’s nutrients directly to your plants’ roots. Eco sustainable resorce for your gardening enjoyment!
Renew Organics 100% Organic Worm Castings (3lbs) – Earthworm Fertilizer & Soil Amendment for Indoor Outdoor Plants Gardens Vegetables – Odorless Non-Burning Pet Safe
- Enhances Soil Health Naturally: This 100% organic worm castings fertilizer improves soil structure, aeration, and moisture retention, fostering beneficial microbes for long-term garden vitality and reduced watering needs.
- Delivers Essential Nutrients: Packed with plant-available nitrogen, phosphorus, potassium, and trace minerals from earthworm castings, it boosts root development, growth, and yields in vegetables, flowers, and houseplants.
- Safe and Odorless Formula: Non-burning, chemical-free vermicompost is pet-safe, child-safe, and ideal for indoor/outdoor use—perfect for edible crops without any unpleasant smells or risks.
- Versatile Soil Amendment: Mix into potting soil, top-dress beds, or brew compost tea for seed starting, lawns, or container gardening—adaptable to all plant types for sustainable results.
- Eco-Friendly and Sustainable: Sourced through regenerative farming, this pure worm poop fertilizer supports environmental health, promoting a greener planet with every application.
WIGGLE WORM Castings Plus Worm Egg Material, 40-Pounds – Fertilizer for Houseplants, Vegetables, and More – Earthworm Castings to Help Improve Soil Fertility and Aeration
- Product ships in a black-and-white printed bag to lower the cost of the bag
- Wiggle Worm Castings Plus Worm Egg Material is our worm castings mixed with added worm egg material to enhance the microbial activity of your soil while providing aeration and nutrients.
- Wiggle Worm Castings are pure worm castings, not vermicompost containing uneaten worm bedding. It’s one of very few casting products recognized as a fertilizer due to our unique harvesting process.
- Worm egg material is the cocoons the worms lay, and tiny balls of soil mixed with bits of bedding not eaten by our worms. Some debris including small rocks may make it through the sifting process.
- Worm eggs may hatch before or after arrival based on variables in shipping. Potential hatched worms are highly beneficial to your soil structure for soil aeration, nutrient cycling, and more!
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Buying Guide
FAQs
What should I look for when choosing a worm casting fertilizer?
Check if the product is 100% organic and OMRI‑listed, which ensures it meets organic gardening standards. Look for nutrient density, such as higher levels of nitrogen, phosphorus, and potassium, and whether the castings are pure worm poop or mixed with bedding. Also consider the source—US‑made, peat‑free, and sustainably farmed products often have better traceability.
How do the nutrient levels of Uncle Jim’s Black Gold compare to other brands?
Uncle Jim’s advertises castings that are 7× richer in phosphates, 5× richer in nitrogen, and 11× richer in potash than average lawn soil, making it one of the most nutrient‑dense options. Brands like Brut and Wiggle Worm also offer high nutrient content, but they typically highlight purity and OMRI certification rather than specific multiplier claims. If you need a boost in specific macro‑nutrients, Uncle Jim’s may provide the strongest profile.
Is there a benefit to buying larger bags, such as the 30‑lb or 40‑lb options?
Larger bags lower the cost per pound and are ideal for extensive garden beds, raised beds, or multiple containers. They also reduce packaging waste compared with buying several small bags. However, worm castings are potent, so a little goes a long way; be sure you have sufficient storage space to keep the product dry and odorless.
Are there any differences in how the castings are processed that affect plant health?
Wiggle Worm emphasizes a unique harvesting process that yields pure castings without uneaten bedding, which can improve soil aeration and nutrient availability. Urban Worm Company and Brut focus on peat‑free, indoor‑raised castings that are certified organic, providing a clean, contaminant‑free amendment. While all are effective, pure castings may offer slightly better soil structure benefits.
Can I use these worm castings for indoor houseplants as well as outdoor gardens?
Yes, most of the products listed—such as Wiggle Worm, Brut, and Renew Organics—are odorless, non‑toxic, and safe for indoor use. They improve soil texture and moisture retention, which benefits container plants and indoor foliage. Just apply a thin layer at the base of the plant or mix into potting soil to avoid over‑fertilizing.
What added value does a product with worm egg material provide?
Wiggle Worm Castings Plus includes worm egg cocoons, which can hatch into live worms that further enhance soil aeration and microbial activity. This creates a self‑sustaining ecosystem that continuously improves nutrient cycling. The added material may contain small debris, but the overall benefit to soil health can outweigh the minor impurities.
How do I know if a worm casting product is environmentally sustainable?
Look for claims such as “regenerative farming,” “peat‑free,” and “made in the USA” that indicate responsible sourcing. Certifications like OMRI and CDFA also reflect adherence to organic and environmental standards. Brands like Urban Worm Company and Renew Organics specifically mention sustainable practices in their production.
What is the best way to apply worm castings for maximum plant growth?
Mix a handful (about ½ cup) into the top few inches of soil before planting, or sprinkle it around established plants and lightly work it in. For larger applications, blend 1‑2 lb per 100 sq ft of garden bed. Reapply two to three times a year—at planting, mid‑season, and before the final harvest—to maintain nutrient levels.