Comparison: Best Espoma Earthworm Castings (Updated | Nov 11th)
After digging deep (literally), we compared the top Espoma earthworm casting products to see which boosts soil health, plant growth, and garden happiness the most. Spoiler: not all castings are created equal. Let’s break down the best picks so you can grow with confidence—no guesswork needed.
Editor’s Choice
Espoma Organic Earthworm Castings – 4 qt. Bag. 100% Pure with no fillers. Safe
Pure Organic Castings
Best for a specific purpose
- Best for pure organic castings: Espoma Organic Earthworm Castings – 4 qt. Bag. 100% Pure with no fillers. Safe
- Best for potting mix blend: Espoma EC4 Earthworm Castings Potting Mix
- Best for vegan soil booster: Worm Bliss (1 Qt) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants
- Best for compaction reducing: Earth Science – Earthworm Castings – Premium Plant Fertilizer for Indoor & Outdoor Plants – Soil Enhancer for Vegetable Gardens 12lb
- Best for egg-infused castings: WIGGLE WORM Castings Plus Worm Egg Material
- Best for vegan bulk boost: Worm Bliss (8 Qts) – Organic Worm Castings for Plants & Gardening – OMRI-Listed Earthworm Castings for Plants
- Best for odorless eco 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 compact soil enhancer: Earth Science Earthworm Castings – 3 lb—Premium Plant Fertilizer for Indoor & Outdoor Plants – Soil Enhancer for Vegetable Gardens
- Best for humic yield boost: NatureGrow Earth Worm Castings – 1lb Organic Fertilizer with Humic Acid – Pure Worm Castings for Gardening
- Best for vegan gallon power: Worm Bliss (1 Gallon) – Organic Worm Castings for Plants – OMRI-Listed Earthworm Castings Worm Fertilizer – Worm Castings Organic Fertilizer for Plants
Product Comparison: Best Espoma Earthworm Castings
Pure Organic Castings
Espoma Organic Earthworm Castings – 4 qt. Bag. 100% Pure with no fillers. Safe, Non-Toxic Organic Fertilizer and Soil Conditioner. Produces Vigorous Plant Growth While improving Soil Structure.
Espoma
- FOR USE ON: Use Espoma Organic Earthworm Casting on all indoor & outdoor plants including vegetables, trees, shrubs, flowers, & houseplants.
- CONTAINS: Espoma Organic Earthworm Castings are 100% pure with no additives or fillers. Environmentally Safe – No sludges or toxic ingredients
- WHEN / HOW TO USE: Add Earthworm Castings every two months to plants that are actively growing. Apply a ¼ to ½ inch layer to the soil surface. Earthworm Castings can also be used to make fertilizer tea. Ready to use and requires no mixing
- FOR ORGANIC GARDENING: Earthworm Castings are approved for organic gardening; It is a registered Organic Input Material meeting all requirements for organic production
- MADE IN THE USA: Product of the Espoma Company. The leader in natural organics since 1929.
Potting Mix Blend
Espoma EC4 Earthworm Castings Potting Mix, 4-Qt. – Quantity 1212
Espoma
Vegan Soil Booster
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.
Compaction Reducing
Earth Science – Earthworm Castings – Premium Plant Fertilizer for Indoor & Outdoor Plants – Soil Enhancer for Vegetable Gardens 12lb
Earth Science
- Improve Soil Quality: Help improve the quality of your soil with Earth Science Premium Earthworm Castings! These castings are an excellent source of nutrients for plants and help to restore and condition your soil by adding a very pure source of organic matter, feeding the microbes that make soil rich, healthy, and productive, Earthworm Castings also increase water retention. Our Earthworm Castings are 100% vermicompost and do not contain any fillers.
- Reduce Soil Compaction: Worm castings help form soil aggregates which help alleviate compaction and soil crusting. Earthworm Castings also help reduce soil erosion by absorbing and retaining water.
- Better Growth: Earthworm Castings encourage plant growth by feeding and growing plants naturally. This natural fertilizer and soil improver is an excellent option for gardeners who want to keep their gardens as natural as possible.
- Natural Deterrent: Earth Science Earthworm Castings are a natural deterrent for any critters that may find their way into your gorgeous garden. Home produce and flower gardeners will delight in the results from this nutrient-rich soil enhancer.
- Compost Use: Earthworm Castings can be utilized in compost piles and used to make liquid plant food.
Egg-Infused Castings
WIGGLE WORM Castings Plus Worm Egg Material, 40-Pounds – Fertilizer for Houseplants, Vegetables, and More – Earthworm Castings to Help Improve Soil Fertility and Aeration
Wiggle Worm
- 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!
Vegan Bulk Boost
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.
Odorless Eco Fertilizer
Renew Organics 100% Organic Worm Castings (3lbs) – Earthworm Fertilizer & Soil Amendment for Indoor Outdoor Plants Gardens Vegetables – Odorless Non-Burning Pet Safe
Renew Organics
- 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.
Compact Soil Enhancer
Earth Science Earthworm Castings – 3 lb—Premium Plant Fertilizer for Indoor & Outdoor Plants – Soil Enhancer for Vegetable Gardens
Earth Science
- Improve Soil Quality: Help improve the quality of your soil with Earth Science Premium Earthworm Castings! These castings are an excellent source of nutrients for plants and help to restore and condition your soil by adding a very pure source of organic matter, feeding the microbes that make soil rich, healthy, and productive, Earthworm Castings also increase water retention. Our Earthworm Castings are 100% vermicompost and do not contain any fillers.
- Reduce Soil Compaction: Worm castings help form soil aggregates which help alleviate compaction and soil crusting. Earthworm Castings also help reduce soil erosion by absorbing and retaining water.
- Better Growth: Earthworm Castings encourage plant growth by feeding and growing plants naturally. This natural fertilizer and soil improver is an excellent option for gardeners who want to keep their gardens as natural as possible.
- Natural Deterrent: Earth Science Earthworm Castings are a natural deterrent for any critters that may find their way into your gorgeous garden. Home produce and flower gardeners will delight in the results from this nutrient-rich soil enhancer.
- Compost Use: Earthworm Castings can be utilized in compost piles and used to make liquid plant food.
Humic Yield Boost
NatureGrow Earth Worm Castings – 1lb Organic Fertilizer with Humic Acid – Pure Worm Castings for Gardening
NatureGrow
- ORGANIC FERTILIZER & SOIL BUILDER – The two-in-one earth casting contains healthy growth microbes.
- HIGHER YIELD & QUALITY – Organic worm castings increase the yield and quality of vegetable plants.
- VERSATILE – Worm castings for indoor plants feature humic acid for soil pH balance.
- COMPOST-FREE – Organic solutions worm castings are not fed on compost and are suitable for plants.
- NO CHEMICALS – We use no chemicals in the feed, resulting in earthworm castings organic fertilizer.
Vegan Gallon Power
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.
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 key factors should I consider when choosing an earthworm casting product?
Look for purity (100% castings vs. blends with fillers), the size of the package that matches your garden scale, and any certifications such as OMRI‑listed for organic use. Also compare nutrient content, water‑retention benefits, and whether the product includes added worm eggs or other microbial boosters.
How does Espoma Organic Earthworm Castings differ from Espoma EC4 Potting Mix?
Espoma Organic Earthworm Castings are a pure, filler‑free amendment meant to be layered onto soil, while EC4 is a pre‑mixed potting blend that already contains the castings plus peat, perlite, and other components. The Castings provide a concentrated source of nutrients and microbes, whereas EC4 offers a ready‑to‑use growing medium that saves you the step of mixing.
Is Worm Bliss more valuable than the larger Earth Science castings for indoor plants?
Worm Bliss emphasizes a vegan, manure‑free process and includes thorough screening for sand and rock, which can be appealing for indoor growers seeking a clean product. Earth Science castings, however, are sold in larger bulk sizes and focus on soil structure and water retention, making them cost‑effective for larger garden beds. Choose based on whether you prioritize purity and indoor safety or bulk volume and overall soil health.
What are the benefits of products that contain worm egg material, like Wiggle Worm Castings Plus?
Worm egg material adds live cocoons that can hatch into beneficial worms, enhancing aeration, nutrient cycling, and long‑term soil fertility. This can lead to a more active microbial ecosystem compared to pure castings alone, but the presence of small debris means you may see a few particles in the soil.
How do the nutrient profiles of Renew Organics and NatureGrow castings compare?
Both are 100% organic and rich in nitrogen, phosphorus, and potassium, but Renew Organics highlights a higher concentration of trace minerals and a focus on odorless, pet‑safe formulation. NatureGrow adds humic acid for pH balance, which can be beneficial for plants that need a more stable soil environment.
Is there a price advantage to buying larger quantities, such as the 40‑lb Wiggle Worm bag versus smaller 1‑qt options?
Bulk bags like the 40‑lb Wiggle Worm offer a lower cost per pound and are ideal for extensive garden projects, while smaller quart containers are convenient for indoor gardeners or those testing the product. The trade‑off is handling and storage; large bags require more space and may be harder to pour accurately.
Do any of these castings act as natural pest deterrents?
Earth Science castings mention a natural deterrent effect against critters, likely due to the strong scent and microbial activity that can discourage pests. While most castings improve overall plant health, only a few, like Earth Science, specifically market this added benefit.
Can I use these earthworm castings to make liquid fertilizer or compost tea?
Yes, most pure casting products—Espoma, Worm Bliss, Renew Organics, and Earth Science—are suitable for steeping in water to create a nutrient‑rich tea that can be applied as a foliar spray or soil drench. Follow the manufacturer’s recommended dilution rates to avoid over‑fertilizing and to maintain microbial balance.