Comparison: Best Potting Soil Worm Castings (Updated | Nov 11th)
If you’ve ever wondered why your neighbor’s plants look impossibly lush while yours struggle, the secret might be hiding right beneath the surface—worm castings. Not all potting soils are created equal, and when it comes to giving your plants a nutrient-packed boost, the quality of worm castings makes all the difference. In this comparison, we’ll dig into the best potting soils enriched with worm castings, breaking down what works, what doesn’t, and which ones are truly worth every penny for healthier, happier plants.
Editor’s Choice
Best for a specific purpose
- Best for pure usa vermicompost: Back to the Roots Organic Worm Castings for Plants
- Best for coco-coir blend: Harris All Purpose Premium Potting Soil Mix with Worm Castings and Other Nutrients
- Best for family-crafted organic: Brut Organic Worm Castings for Plants 5 LB – Natural Nutrients
- Best for bulk organic power: Brut Organic Worm Castings for Plants 30 LB – Natural Nutrients
- Best for vegan moisture boost: Worm Bliss (1 Qt) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants
- Best for vegan bulk bliss: Worm Bliss (8 Qts) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants
- Best for expandable coco mix: WONDER SOIL Organic Potting Soil | Ready to Plant Coco Coir Fully Loaded with Nutrients | 3 LBS Bag Expands to 12 Quarts of Indoor Outdoor Soil for Gardens & Plants | Incl Worm Castings
- Best for vegan gallon boost: Worm Bliss (1 Gallon) – Organic Worm Castings for Plants – OMRI-Listed Earthworm Castings Worm Fertilizer – Worm Castings Organic Fertilizer for Plants
- Best for pure fertilizer castings: Wiggle Worm 100% Pure Organic Worm Castings Fertilizer
- Best for vegan two gallon: Worm Bliss (2 Gallons) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants
Product Comparison: Best Potting Soil Worm Castings
Pure USA Vermicompost
Back to the Roots Organic Worm Castings for Plants, Natural Fertilizer and Soil Enhancer for Gardening, Made in The USA, 5lb
Back to the Roots
- Earth Worm castings from Mother Earth provide the best soil amendment for anything indoors or outdoors, including vegetables, herbs, flowers and houseplants. Pure USA Vermicompost, so there’s no burn or odor.
- Contains beneficial microbes to enhance your soil and protect seedlings from harmful pathogens.
- Develop your garden more sustainably as worm castings reduce the need for fertilizers.
- 100% SATISFACTION GUARANTEE: If you are not satisfied or have any issues with this Organic Worm Castings, just shoot us a note and our dedicacted customer support team will make sure we get you growing or send you a refund/replacement.
- #GROWONEGIVEONE — share a photo of garden with #GrowOneGiveOne and we’ll donate an Organic Gardening Kit + STEM curriculum to an elementary school classroom of your choice!
Coco-Coir Blend
Harris All Purpose Premium Potting Soil Mix with Worm Castings and Other Nutrients, 4 Quarts
HARRIS
- All Purpose Potting Mix – Use indoors and outdoors for container gardening, flower boxes, hanging baskets and more
- Contains Worm Castings – A plant superfood, worm castings provide essential nutrients to plants including iron, sulfur, calcium, nitrogen, phosphorus and potassium
- Fast Drainage – Contains pumice and perlite to promote aeration of roots and fast drainage
- Formulated with Coco Coir – A sustainable resource that helps maintain moisture for vibrant flowers, vegetables and herbs
Family-Crafted Organic
Brut Organic Worm Castings for Plants 5 LB – Natural Nutrients, Fertility Builder, Plant Food for Potting Soil and Garden Soil – Indoor and Outdoor Use
BRUT WORM FARMS
- 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!
Bulk Organic Power
Brut Organic Worm Castings for Plants 30 LB – Natural Nutrients, Fertility Builder, Plant Food for Potting Soil and Garden Soil – Indoor and Outdoor Use
BRUT WORM FARMS
- 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!
Vegan Moisture Boost
Worm Bliss (1 Qt) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants, Vegetables, Flowers, & Potting Soil – Organic Garden Fertilizer Rich in Nutrients
plantonix
- Organic Worm Castings for Garden Soil – Plantonix Worm Bliss is a 100% organic fertilizer and soil amendment that mixes with potting soil for indoor plants and outdoor plants. Worm castings are rich in essential nutrients like nitrogen, phosphorus, and potassium, as well as trace minerals that improve soil conditions for better overall plant mass.
- 100% Vegan & Manure-Free – We raise our worms in a climate controlled facility and feed them a strictly vegan diet. Our earth worm castings for plants are meticulously screened to get rid of any traces of dirt, sand, or rocks, leaving you with nothing but pure worm castings for plants, unlike others who dilute their castings with synthetic ingredients or additives.
- Supports Beneficial Microbial Activity – Using earthworm castings for plants encourages soil microbes that break down organic matter and convert nutrients into forms that plants can easily absorb. These microbes are crucial for increasing nutrient availability and building drought tolerance for a more balanced soil ecosystem.
- Excellent Water Retention – The humus in worm castings improves the soil’s ability to retain moisture, so you can rest assured knowing your plants are staying happy and hydrated. Worm humus for plants reduces the need for frequent watering, so you can save water and promote more sustainable gardening practices.
- Improves Soil Structure & Aeration – Using organic worm castings for plants increases the porosity of the soil, creating a well-oxygenated environment that supports efficient water and nutrient uptake. This makes earth worm castings organic fertilizer an excellent choice for plants, potting soil, potting mixes, garden containers, garden terraces, flowers, garden soil for vegetables, and more.
Vegan Bulk Bliss
Worm Bliss (8 Qts) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants, Vegetables, Flowers, & Potting Soil – Organic Garden Fertilizer Rich in Nutrients
plantonix
- Organic Worm Fertilizer for Plants – Worm castings are a 100% natural soil amendment and garden fertilizer for indoor plants and outdoor plants. Organic earthworm castings are rich in essential nutrients like nitrogen, phosphorus, and potassium, as well as trace minerals that improve soil conditions for better overall plant mass.
- 100% Vegan & Manure-Free – We raise our worms in a climate controlled facility and feed them a strictly vegan diet. The castings are meticulously screened to get rid of any traces of dirt, sand, or rocks, leaving you with nothing but pure worm castings for plants, unlike others who dilute their castings with synthetic ingredients or additives.
- Supports Microbial Activity – Using earthworm castings for plants encourages soil microbes that break down organic matter and convert nutrients into forms that plants can easily absorb. These microbes are crucial for increasing nutrient availability and building drought tolerance for a more balanced soil ecosystem.
- Excellent Water Retention – The humus in worm castings improves the soil’s ability to retain moisture, so you can rest assured knowing your plants are staying happy and hydrated. This reduces the need for frequent watering, so you can save water and promote more sustainable gardening practices.
- Improves Soil Structure & Aeration – Using organic worm castings for plants increases the porosity of the soil, creating a well-oxygenated environment that supports efficient water and nutrient uptake. This makes Worm Bliss an excellent plant fertilizer for potting soil, potting mixes, garden containers, garden terraces, vegetables, flowers, and more.
Expandable Coco Mix
WONDER SOIL Organic Potting Soil | Ready to Plant Coco Coir Fully Loaded with Nutrients | 3 LBS Bag Expands to 12 Quarts of Indoor Outdoor Soil for Gardens & Plants | Incl Worm Castings, Perlite
Wonder Soil
- NUTRIENT RICH & INDOOR/OUTDOOR FAST GERMINATION… Wonder Soil Premium Organic Potting Soil Mix is the only dry compressed coco coir mix with added amendments of worm castings, mycorrhizae, kelp, perlite and more! Grow your plants faster with stronger roots! Peat free, all natural, family and pet safe!
- A LITTLE DOES A LOT… your little BIG bag of compressed indoor potting soil & garden soil for outdoor plants expands to 4 TIMES THE SIZE when mixed with water; easy to carry & saves vital shed space.
- PRE-MIXED & READY TO USE ORGANIC POTTING MIX … Pre-mixed and ready to use organic potting soil and garden soil mix to help make your gardening or hobby growing a breeze. Simply transplant your desired plants into their new container and add our soil mix or pour our soil mix and plant your seeds.
- WATER RETENTION & DRAINAGE… Coco coir has excellent water retention with dependable drainage and aeration in the root zone. Save up to 50% of water, fertilizer, and seed!
- HEAVY DUTY RESEALABLE BAG… Use what you need and save the rest for later! Keeping your planting soil dry and safe!
Vegan Gallon Boost
Worm Bliss (1 Gallon) – Organic Worm Castings for Plants – OMRI-Listed Earthworm Castings Worm Fertilizer – Worm Castings Organic Fertilizer for Plants, Potting Soil, Garden Soil, & Seed Starter Soil
plantonix
- Organic Worm Castings for Garden Soil – Plantonix Worm Bliss is a 100% organic fertilizer and soil amendment that mixes with potting soil for indoor plants and outdoor plants. Worm castings are rich in essential nutrients like nitrogen, phosphorus, and potassium, as well as trace minerals that improve soil conditions for better overall plant mass.
- 100% Vegan & Manure-Free – We raise our worms in a climate controlled facility and feed them a strictly vegan diet. Our earth worm castings for plants are meticulously screened to get rid of any traces of dirt, sand, or rocks, leaving you with nothing but pure worm castings for plants, unlike others who dilute their castings with synthetic ingredients or additives.
- Supports Beneficial Microbial Activity – Using earthworm castings for plants encourages soil microbes that break down organic matter and convert nutrients into forms that plants can easily absorb. These microbes are crucial for increasing nutrient availability and building drought tolerance for a more balanced soil ecosystem.
- Excellent Water Retention – The humus in worm castings improves the soil’s ability to retain moisture, so you can rest assured knowing your plants are staying happy and hydrated. Worm humus for plants reduces the need for frequent watering, so you can save water and promote more sustainable gardening practices.
- Improves Soil Structure & Aeration – Using organic worm castings for plants increases the porosity of the soil, creating a well-oxygenated environment that supports efficient water and nutrient uptake. This makes earth worm castings organic fertilizer an excellent choice for plants, potting soil, potting mixes, garden containers, garden terraces, flowers, garden soil for vegetables, and more.
Pure Fertilizer Castings
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
Wiggle Worm
- 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
Vegan Two Gallon
Worm Bliss (2 Gallons) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants, Vegetables, Flowers, & Potting Soil – Organic Garden Fertilizer Rich in Nutrients
plantonix
- Organic Worm Castings for Garden Soil – Plantonix Worm Bliss is a 100% organic fertilizer and soil amendment that mixes with potting soil for indoor plants and outdoor plants. Worm castings are rich in essential nutrients like nitrogen, phosphorus, and potassium, as well as trace minerals that improve soil conditions for better overall plant mass.
- 100% Vegan & Manure-Free – We raise our worms in a climate controlled facility and feed them a strictly vegan diet. Our earth worm castings for plants are meticulously screened to get rid of any traces of dirt, sand, or rocks, leaving you with nothing but pure worm castings for plants, unlike others who dilute their castings with synthetic ingredients or additives.
- Supports Beneficial Microbial Activity – Using earthworm castings for plants encourages soil microbes that break down organic matter and convert nutrients into forms that plants can easily absorb. These microbes are crucial for increasing nutrient availability and building drought tolerance for a more balanced soil ecosystem.
- Excellent Water Retention – The humus in worm castings improves the soil’s ability to retain moisture, so you can rest assured knowing your plants are staying happy and hydrated. Worm humus for plants reduces the need for frequent watering, so you can save water and promote more sustainable gardening practices.
- Improves Soil Structure & Aeration – Using organic worm castings for plants increases the porosity of the soil, creating a well-oxygenated environment that supports efficient water and nutrient uptake. This makes earth worm castings organic fertilizer an excellent choice for plants, potting soil, potting mixes, garden containers, garden terraces, flowers, garden soil for vegetables, 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 are the key differences between pure worm castings and blended potting mixes?
Pure worm castings, like Back to the Roots or Worm Bliss, provide a concentrated source of nutrients, microbes, and humus without added fillers. Blended mixes, such as Harris All Purpose or Wonder Soil, combine castings with perlite, coco coir, or other amendments to improve drainage and structure. Choose pure castings if you want a high‑nutrient amendment, or a blend if you need a ready‑to‑use soil that balances moisture retention and aeration.
How does the nutrient content of Back to the Roots Organic Worm Castings compare to Brut Organic Worm Castings?
Both products are certified organic and rich in nitrogen, phosphorus, and potassium, but Brut emphasizes a family‑crafted, indoor‑raised formula that is OMRI and CDFA listed, suggesting stricter testing standards. Back to the Roots highlights beneficial microbes and a burn‑free guarantee, making it a solid choice for sensitive indoor plants. Overall, nutrient levels are comparable, with Brut slightly edging ahead on certification and purity claims.
Which product offers the best value for large‑scale gardening projects?
For bulk applications, Brut Organic Worm Castings in the 30 lb bag and Wiggle Worm’s 30‑pound pure castings provide the lowest cost per pound of nutrient‑dense material. Both are OMRI‑listed and designed for outdoor use, delivering high nutrient density without dilution. If you need additional soil structure, Harris All Purpose’s 5‑gal mix offers a good balance of castings and drainage agents at a moderate price.
Are vegan, manure‑free castings like Worm Bliss worth the premium price?
Worm Bliss products are 100 % vegan, screened for dirt and rock particles, and emphasize microbial activity and water retention, which can reduce watering frequency. The premium reflects the controlled production environment and the added convenience of a clean, odor‑free product. Gardeners who prioritize sustainability and consistent quality often find the extra cost justified.
How important is the presence of additional amendments such as perlite, coco coir, or mycorrhizae?
Amendments like perlite and coco coir improve aeration and drainage, preventing root rot in heavier soils, while mycorrhizae enhance nutrient uptake and plant resilience. Products like Harris All Purpose and Wonder Soil include these components, making them ideal for containers or fast‑draining mixes. If you already have well‑draining soil, pure castings may suffice; otherwise, a blended mix can simplify soil preparation.
What should I consider when choosing a size (e.g., 1 qt vs 30 lb) for my garden?
Small containers such as 1 qt or 1 gallon are perfect for indoor houseplants or trial batches, allowing you to test performance without waste. Larger bags (30 lb or 8 qt) are cost‑effective for raised beds, vegetable plots, or commercial growers who need consistent amendment across many plants. Match the package size to the scale of your project and storage space to avoid spoilage.
Do OMRI‑listed castings provide any certification advantage over non‑listed products?
OMRI listing confirms that the product meets organic standards for use in certified organic production, which can be important for growers seeking compliance. It also signals rigorous testing for contaminants and consistent nutrient profiles. While non‑listed castings can still be effective, OMRI certification adds a layer of trust for organic gardeners.
How do water retention and aeration differ among the listed products?
Pure castings like Worm Bliss and Wiggle Worm naturally improve water retention due to high humus content, but they may compact if used alone. Blended mixes that include perlite, pumice, or coco coir—found in Harris All Purpose and Wonder Soil—enhance aeration and prevent waterlogging. Selecting a product depends on whether you prioritize moisture retention (pure castings) or balanced drainage (blended mixes).