Table of Contents

4 sections 6 min read

Your grain spawn is fully colonized, your monotub is clean, yet you are paused at the bulk stage wondering whether to choose manure richness or woody power. This decision shapes colonization speed, flush size and how much attention your grow will demand over the next few weeks.

Compare prices: Walmart · eBay · Target
Prices vary by seller — check live price at each store.
Chot nhanh: xem 3 lua chon dang duoc doc nhieu nhat trong bai — xem bang so sanh

This 2026 guide to best manure substrate for mushroom vs masters mix is for home growers moving from spawn to bulk. We evaluated texture, hydration, nutrient design and workflow fit across 10 options from Out-Grow, NorthSporeMushrooms, MushroomMediaOnline and more, including a helpful comparison in our substrate bag comparison for Myco Labs users.

This article contains affiliate links. If you buy through one of our links, FungiPop may earn a commission at no extra cost to you. Commissions never influence which products we recommend or how we rank them. Read our Affiliate Disclosure for details.

Quick Picks at a Glance

Editor's Pick
SGM LABS 5 LB Coco Mushroom Substrate with Cow Manure, CVG Sterilized Mix for Monotub
SGM LABS

Prime SGM LABS 5 LB Coco Mushroom Substrate with Cow

★ ★ ★ ★ ★
4.6 (100)
$20.99
View on Amazon.com
September 16, 2026

As an Amazon Associate we earn from qualifying purchases. Product prices and availability are accurate as of the date/time indicated.

1
Prime Best Seller

Boomer Shroomer CVG Mushroom Substrate

BoomerShroomer
In Stock
9.8 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
This dry CVG bulk substrate combines coco coir, vermiculite and gypsum to make about 9 lbs of hydrated mix for two monotubs. It is a strong pick for beginners and experienced growers who want simple bucket prep with reliable moisture retention for spawn to bulk transfers.
Pros & Cons

Pros

  • Balanced CVG blend designed specifically for mushroom cultivation
  • Excellent moisture retention with added aeration from vermiculite
  • Large yield covers two monotubs from one bag
  • Easy to store dry mix with long shelf life

Cons

  • Requires boiling water, a 5 gallon bucket and a 24 hour pasteurization wait
  • Bucket and other prep supplies are not included
  • Fixed blend ratio offers less customization for advanced recipes
Detailed Review

The Boomer Shroomer Dry Bulk Substrate is a ready to mix CVG blend of coco coir, vermiculite and gypsum for mushroom cultivation. It is built for hobby mycologists and beginners doing spawn to bulk transfers in monotubs, trays or filter bags.

In use, you simply add 16 cups of boiling water in a 5 gallon bucket and let it pasteurize for 24 hours to reach field capacity. The hydrated mix delivers about 9 lbs of airy, moisture retentive substrate that supports fast colonization and multiple flushes.

The ingredient quality stands out, with coco coir for water holding, vermiculite for aeration and gypsum for pH stability. The dry format keeps everything fresh in storage, lightweight to handle, and less prone to contamination than pre hydrated products.

The main tradeoff is prep time, since you need boiling water, a bucket and a full day wait before use. Growers who want instant ready to use substrate or custom ratios will need to look elsewhere or adjust on their own.

Overall, this is a reliable, beginner friendly bulk substrate that simplifies monotub growing without sacrificing performance. If you want a consistent CVG base for two full tubs, it is an easy recommendation.

Specifications

Brand: Boomer Shroomer, Model: BSBULK001, Type: Dry CVG bulk substrate. Includes 500g coco coir, 500g vermiculite and 100g gypsum.

Hydrated yield is about 9 lbs, enough for two monotubs. Dry weight is 1.15 kg with a 5 gallon prep volume using bucket tek.

How to Use

Add the dry mix to a clean 5 gallon bucket, pour in 16 cups of boiling water, seal and let pasteurize for 24 hours. Check for field capacity where the mix holds moisture without dripping.

Mix with fully colonized grain spawn for spawn to bulk transfer in monotubs, trays or bags. Maintain proper humidity and fresh air exchange for colonization and fruiting.

2
Prime Editor's Pick

SGM LABS 5 LB Coco Mushroom Substrate with Cow

SGM LABS
In Stock
9.8 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
The SGM LABS 5 LB Cow Coco mushroom substrate is a pre-hydrated CVG mix with coco coir, cow manure, vermiculite and gypsum for monotub and grow in bag use. It stands out for fast colonization and strong moisture retention, making it ideal for beginners and bulk hobby growers.
Pros & Cons

Pros

  • Fast colonization reported by beginners and experienced growers
  • Clean performance with strong contamination resistance
  • Holds moisture well without need for rehydration
  • Truly ready to use right out of the bag
  • Works for multiple methods including monotubs and in bag grows

Cons

  • 5 LB size may require multiple bags for large monotubs or bulk runs
  • Pre-hydrated format is heavier and bulkier to store than dry coir bricks
  • Natural manure based mix may have an earthy odor during setup
Detailed Review

The SGM LABS 5 LB Cow Coco Substrate is a pre-hydrated CVG blend made with coco coir, cow manure, vermiculite and gypsum. It is built for first time growers, hobbyists and bulk cultivators who want a ready to use fruiting substrate without mixing their own.

In real world use, it stands out for fast colonization and reliable fruiting performance in monotubs and grow in bag setups. Reviewers consistently note clean runs with strong moisture retention, often reporting no need to mist again after spawning.

The substrate arrives pre-hydrated in a 0.2 micron filter bag that allows gas exchange while limiting contaminants. Each bag includes a production date and batch number sticker, which adds confidence in freshness and small batch quality control.

The main tradeoff is size and format, since larger tubs will need multiple bags and the pre-hydrated weight is bulkier than dry coir bricks. The manure enriched formula can also have a natural earthy smell during setup.

Overall, this is an excellent plug and play substrate for growers who value convenience, consistency and yield. If you want to skip pasteurizing and mixing and get straight to spawning, it is a smart, dependable choice.

Specifications

Brand: SGM LABS, Model Number: 5lbcowcocosubstrate, Item Type: cowcoco, Style: Modern.

Unit Count: 80 Fluid Ounces, Item Weight: 5 pounds, Volume: 6.54 quarts.

Mix: Coco coir, cow manure, vermiculite and gypsum in a pre-hydrated 0.2 micron filter bag for monotub, casing or in bag growing.

How to Use

Use this substrate straight from the bag with no mixing or hydrating required. Simply dump into a clean monotub or spawn your colonized grain directly into the CVG bag.

Maintain proper fresh air exchange and stable temperatures during colonization and fruiting. The pre-hydrated formula is designed to hold moisture, so avoid over misting early on.

For best results, keep your work area clean during transfer and follow standard spawn to substrate ratios. Store unopened bags in a cool, dry place and check the batch date sticker for freshness.

3
Prime Limited Time

Masters Mix Fast Fruiting Pellets 40lb

MushroomMediaOnline
In Stock
9.8 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
This 40-pound Masters Mix blends 50% oak and 50% soy hull pellets to speed colonization and boost yields. It is ideal for hobbyists and small commercial growers raising oysters, shiitake and lion's mane.
Pros & Cons

Pros

  • Proven Masters Mix ratio trusted for fast colonization
  • Versatile across popular gourmet species
  • Uniform pellets for easy hydration and mixing
  • Bulk 40lb size supports repeated grows without frequent reordering

Cons

  • No printed prep instructions in the bag, beginners must research steps
  • Requires pressure sterilization for best results and extra equipment
  • Heavy 40lb bag needs dry storage and can be bulky for small spaces
Detailed Review

This is a 40-pound bag of Masters Mix, a 50/50 blend of oak pellets and soy hull pellets designed as a high nutrition substrate for gourmet mushrooms. It is built for hobbyists and small commercial growers who want faster runs of oysters, shiitake, lion's mane and similar species.

The standout benefit is speed and yield. The soy component adds nitrogen that fuels aggressive mycelium growth, and growers report visible colonization in days with healthy flushes to follow. When properly hydrated and sterilized, it consistently outperforms plain sawdust or straw.

Quality is uniform and clean, with dense hardwood style pellets that break down evenly when water is added. The fine texture packs well into grow bags or buckets and creates an even surface for full colonization. Storage is simple if kept dry, and the bulk size suits repeated batches.

There are a few tradeoffs to know. The bag does not include detailed prep directions, so beginners will need to look up hydration ratios and sterilization steps. You will also need a pressure cooker or sterilizer for best results, and the heavy bag can be awkward to handle and store.

Overall, this is a reliable, high performance substrate for anyone serious about growing gourmet mushrooms at home or on a small farm. If you want faster colonization, bigger harvests and a proven mix without sourcing ingredients separately, it is an excellent pick.

Specifications

Brand: MushroomMediaOnline, Form: Fast fruiting pellets, Blend: 50 percent oak plus 50 percent soy hulls.

Bag Size: 40 pounds, Prep: Hydrate, sterilize and inoculate for grow bags, buckets and containers.

Best For: Oyster mushrooms, shiitake, lion's mane and other wood loving gourmet species for hobby and commercial use.

How to Use

Start by hydrating the pellets with clean water until they expand into loose, even sawdust. Fill mushroom grow bags or buckets, then pressure sterilize to create a clean base for inoculation.

Once cool, add your colonized grain spawn, seal and incubate until fully colonized. Then expose to fresh air, humidity and light to trigger fruiting and harvest.

4
Prime Top Rated

SGM LABS 10 LB Coco Mushroom Substrate CVG

SGM LABS
In Stock
9.7 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
This 10 lb pre-hydrated CVG substrate blends coco coir, cow manure, vermiculite and gypsum and arrives sterilized and ready to use. Its consistent moisture and clean, contamination free performance make it a strong pick for beginners and bulk monotub growers.
Pros & Cons

Pros

  • Perfectly hydrated out of the bag with no prep work required
  • Clean sterilized substrate with strong resistance to contamination
  • Fast colonization reported by beginner and experienced growers
  • Flexible use in monotubs, as casing, or in bag growing
  • Quality CVG plus cow manure for improved nutrition and yields

Cons

  • Spawned grain must be purchased separately to start growing
  • 10 lb size may require multiple bags for large monotubs or bulk runs
  • Sterility depends on careful handling once the bag is opened
Detailed Review

This 10 lb Cow Coco substrate from SGM LABS is a sterilized CVG mix made for mushroom fruiting in monotubs, as casing, or directly in the bag. It is built for first time growers, hobbyists, and bulk cultivators who want a ready to use solution without mixing their own substrate.

The blend combines coco coir, cow manure, vermiculite, and gypsum to supply nutrition, moisture retention, and structure for mycelium growth. In real world use, growers report fast colonization, ideal hydration, and clean runs with no contamination when good sterile technique is followed.

Build quality centers on the pre-hydrated 0.2 micron filter bag that keeps the substrate sterile until you are ready to inoculate. The 10 pound, 7 liter fill provides solid volume for standard tubs while staying manageable to pour, mix, and store.

There are a few limits to plan for, including the need to supply your own spawned grain and maintain sterility after opening. Large scale grows may need multiple bags, and the bag is bulky to handle and store compared to dry compressed bricks.

Overall, this is a reliable, beginner friendly, high yield substrate that removes guesswork from prep and hydration. If you want consistent moisture, clean performance, and flexible growing options, it is an excellent choice for your next run.

Specifications

Brand: SGM LABS, Item Type: Cow Coco CVG Substrate, Weight: 10 pounds

Volume: 7 liters, Unit Count: 160 fluid ounces, Style: Modern

Material Blend: Coco coir, cow manure, vermiculite and gypsum, Bag Filter: 0.2 micron sterilized fruiting bag

Use Methods: Monotub fill, casing layer, or grow in bag, Manufacturer Part Number: 10lbcowcocosubstrate

5
Prime

SGM LABS 5 LB Black Coco Mushroom Substrate

SGM LABS
In Stock
9.6 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
The SGM LABS 5 LB Black Coco Substrate is a pre-hydrated, sterilized CVG mix of coco coir, vermiculite and gypsum for fruiting mushrooms. It is best for beginners, hobbyists and bulk growers who want a ready to use, contamination resistant monotub medium.
Pros & Cons

Pros

  • Proven CVG blend balances moisture retention, aeration and nutrition for strong colonization
  • Truly ready to use with no prep, saving time and eliminating hydration mistakes
  • Sterile packaging supports cleaner grows with less competition from contaminants
  • Flexible application for monotubs, casing layers or in-bag fruiting

Cons

  • Requires separate colonized grain spawn, it is not an all-in-one grow kit
  • 5 pound bag may require multiple units for large bulk monotub runs
  • Sterility depends on proper handling after opening, so clean technique is still essential
Detailed Review

The SGM LABS 5 LB Black Coco Mushroom Substrate is a bulk CVG substrate built for spawned grain to fruit. It suits first time growers, hobbyists and bulk cultivators who want to skip mixing and pasteurizing at home.

Its standout is the classic coco coir, vermiculite and gypsum blend, pre-hydrated to field capacity for fast colonization. The vermiculite holds moisture while gypsum supports structure, which promotes even mycelium runs and fuller flushes.

Design centers on convenience and cleanliness. The substrate arrives sterilized in a 0.2 micron filter bag that limits exposure to contaminants while allowing proper gas exchange for healthy mycelium.

The main limitation is that it is substrate only, so you still need live grain spawn and good sterile technique. Larger monotub builds may also need more than one 5 pound bag for ideal depth.

Overall, this is a practical, time saving base for monotub, casing or grow in bag methods. If you want a clean, ready to pour CVG mix from a dedicated mushroom supplier, this is a solid pick.

Specifications

Brand: SGM LABS, Style: mushroom grow bag, Item Type: bulk mushroom substrate.

Weight: 5 pounds, Volume: 80 fluid ounces, 240 cubic inches, CVG blend of coco coir, vermiculite and gypsum.

Packaging: Pre-hydrated and sterilized 0.2 micron filter bag, UPC: 712198404774, ASIN: B0CR9WXH4J.

How to Use

Use as monotub fill by dumping the ready to use substrate into a clean tub and mixing with colonized grain. No additional hydration or pasteurization is required.

Use as a casing layer over colonized bulk or fruit directly in the bag by adding grain spawn to the CVG bag. Maintain clean hands, tools and fruiting conditions for best results.

6
Prime

Out-Grow Pasteurized Horse Manure Mushroom

Out-Grow
In Stock
9.6 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
This is a 5-pack of 1-pound pasteurized horse manure based bulk substrate from Out-Grow for growing gourmet mushrooms at home. With balanced moisture, pH and filter bags for clean colonization, it is ideal for beginners and hobby growers who want a ready to use mix.
Pros & Cons

Pros

  • Ready to use pasteurized formula saves prep time and lowers contamination risk
  • Split 5 x 1lb packaging is convenient for small batches and keeps unused portions fresh
  • Balanced moisture, pH and added nutrients optimized for mycelium growth
  • Filter patch bags promote healthy gas exchange while helping block contaminants

Cons

  • Natural manure base has an earthy odor that may be noticeable during handling
  • 5 pound total volume may be small for large bulk grows and require multiple packs
  • Best performance comes from fresh use, extended storage can reduce vitality
Detailed Review

Out-Grow Pasteurized Horse Manure Based Mushroom Bulk Substrate is a ready to use growing medium for cultivating gourmet mushrooms at home. It is ideal for beginners, hobby growers and anyone who wants to avoid the hassle of mixing and sterilizing their own substrate.

The mix arrives 100 percent pasteurized to create a clean starting environment for mycelium. It is enriched with vitamins and minerals and pre balanced for moisture and pH, which helps support fast colonization and robust flushes when paired with quality spawn.

Build quality centers on convenience and cleanliness. The substrate comes in five sealed 1 pound bags with built in filter patches that allow fresh gas exchange while helping keep contaminants out, making dosing and small batch grows simple.

There are a few tradeoffs to consider. The natural manure base has an earthy odor that some indoor users may notice during handling and storage. The 5 pound total is great for starter projects but larger bulk grows will need multiple packs, and freshness matters for best performance.

Overall, this is a practical, beginner friendly option for clean and consistent mushroom cultivation. If you want a nutritious, ready to use bulk substrate without prep work, this Out-Grow 5 pack is a smart pick for your home grow setup.

Specifications

Brand: Out-Grow, Form: Pasteurized bulk substrate in bags, Unit Count: Five 1 pound bags, 80 ounces total.

Base Material: Horse manure blend enriched with vitamins and minerals to support mycelium growth.

Packaging: Pre sealed bags with built in filter patches for gas exchange and contamination protection.

Storage: Store in a cool, dry place for up to 4 months. Best used fresh for optimal colonization.

7
Prime

Myco Labs Premium 5 LB Pasteurized Bulk Mushroom

MycoLabs
In Stock
9.6 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
Myco Labs Premium Bulk Mushroom Substrate Mix is a pre-hydrated, pasteurized 5 lb bag built for dung and grain loving mushrooms. With balanced pH, preserved nutrients and ideal field capacity moisture, it is best for beginners and experienced growers using grain spawn.
Pros & Cons

Pros

  • Ready to use with no prep, just add grain spawn
  • Excellent moisture retention held at field capacity
  • pH balanced formula supports fast, healthy colonization
  • Beginner friendly yet effective for experienced growers

Cons

  • Recent switch to vacuum sealed bags reported as wetter than previous filter patch bags
  • Some users noted an off smell and reduced success with newer batches
  • Formulated only for dung and grain loving types, not universal for all mushrooms
Detailed Review

Myco Labs Premium Bulk Mushroom Substrate Mix is a pasteurized, pre-hydrated 5 lb substrate designed for dung and grain loving mushrooms. It is made for home cultivators who want a convenient, ready to use base to mix with grain spawn without measuring or hydrating from scratch.

The standout is the gentle pasteurization process that retains beneficial nutrients and nitrates for mycelium instead of destroying them. Combined with high water retention at field capacity and a calcium enriched pH balance, users report fast colonization and satisfying yields with proper technique.

Each bag comes pre-hydrated and pasteurized in a bulk 5 lb format that is simple to handle and apply. The texture is formulated to stay moist yet airy, giving mycelium the stable, supportive environment it needs to spread evenly.

Performance is not perfect for everyone, as some long term users report recent batches in vacuum sealed packaging feel wetter and have an unusual smell. Those reports mention lower success rates compared to the older filter patch bags, so consistency can vary.

Overall, this is a strong time saving option for beginners and experienced growers focused on dung loving varieties. If you want convenience, balanced nutrition and reliable moisture out of the bag, it is a practical pick when used with good sterile practice.

Specifications

Brand: Myco Labs, Item Type: Substrate Bag, Unit Count: 80 Fluid Ounces.

Item Weight: 5 pounds, Volume: 5 liters, Style: American.

Compatibility: Designed for dung and grain loving mushrooms for use with grain spawn, pre-hydrated and pasteurized for immediate use.

8
Prime

Out-Grow 5lb Pasteurized Horse Manure Mushroom

Out-Grow
In Stock
9.5 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
This 5lb ready to use grow bag from Out-Grow combines pasteurized horse manure, straw, coco coir, vermiculite and worm castings for bulk cultivation. It is ideal for home mycologists who want a rich, pre hydrated monotub substrate without mixing or pasteurizing.
Pros & Cons

Pros

  • Ready to inoculate with no additional hydration or pasteurization needed
  • Diverse ingredient mix designed to improve nutrition, aeration and moisture retention
  • Convenient for beginners and experienced growers using monotubs or bulk methods
  • Stores for months at room temperature for flexible grow timing

Cons

  • 5 quart capacity may require multiple bags for large monotub projects
  • Spawn is not included, so you will need to purchase colonized grain separately
  • Indoor use only and must be stored away from sunlight to maintain quality
Detailed Review

The Out-Grow 5lb Mushroom Grow Bag is a pasteurized bulk substrate built around horse manure and chopped wheat straw, enriched with coco coir, vermiculite, worm castings and gypsum. It is made for home growers who want to skip mixing and pasteurizing and move straight to spawning in a monotub or bulk setup.

The standout benefit is the complete, ready to inoculate formulation that arrives properly hydrated for immediate use. In real world use, the manure and straw base provides rich nutrition and structure, while coir and vermiculite help retain moisture and improve aeration for steady colonization and productive flushes.

Build quality is practical and grower focused, with a clean rectangular 6 x 12 x 6 inch bag that is easy to handle, open and mix with spawn indoors. The materials feel evenly blended and properly moist, not soggy or dry, which helps reduce contamination risk from improper field capacity.

The main limitations are capacity and scope, since one 5lb bag fills about 5 quarts and larger monotubs will need multiple bags plus separate grain spawn. It is also indoor only and needs room temperature storage away from sunlight to preserve sterility and moisture over time.

Overall, this is a convenient, nutrient rich shortcut for growers who value consistency and time savings over DIY prep. If you want a reliable manure based substrate from a specialist brand with long mycology experience, this bag is a strong pick for your next bulk grow.

Specifications

Brand: Out-Grow

Product Type: Pasteurized mushroom grow bag substrate, 5lb bag with 5 quart capacity

Ingredients: Horse manure, chopped wheat straw, coco coir, vermiculite, worm castings, gypsum, spring water

Dimensions: 6 x 12 x 6 inches, rectangular free standing bag format

Intended Use: Indoor bulk cultivation and monotub setups, ready for inoculation with mushroom spawn

How to Use

Store the sealed bag at room temperature away from direct sunlight until you are ready to grow. When ready, open in a clean area and mix evenly with your fully colonized grain spawn according to your chosen spawn to substrate ratio.

Place the mixture into a monotub or bulk container, then incubate in warm, dark conditions until fully colonized. Maintain proper humidity and fresh air exchange during fruiting for best results.

9
Prime

North Spore Boomr Bag 5 lb Sterile Manure-Based

NorthSporeMushrooms
In Stock
9.5 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
The North Spore Boomr Bag is a 5 lb sterile manure-based bulk substrate made with composted horse manure and coco coir. Its mycologist-formulated blend is ideal for growers of dung-loving species using monotubs, filter bags or outdoor beds.
Pros & Cons

Pros

  • Sterile and ready to use with no pasteurization, mixing or hydration required
  • Formulated specifically for dung-loving species to support fast colonization and better yields
  • Works across multiple methods, ideal for beginners and experienced bulk growers
  • Filter patch bag and moisture balanced texture for healthy mycelium growth
  • Made in USA with quality composted manure and coco coir base

Cons

  • Exact supplement blend is proprietary, so you cannot adjust the recipe
  • Requires separate colonized grain spawn, not an all in one grow kit
  • Single 5 lb bag may not be enough for large monotubs or outdoor beds
Detailed Review

The North Spore Boomr Bag is a 5 lb sterile bulk substrate built for dung loving mushroom species. It is made for beginners and experienced growers who want a ready to use base for monotubs, bags and outdoor beds.

The blend combines composted horse manure, coco coir and added supplements to support strong colonization and improved yields. Because it arrives sterile and hydrated to field capacity, you can mix it directly with colonized grain spawn without extra prep.

Built in a filter patch bag, it allows proper gas exchange while helping reduce contamination risk. The texture holds moisture well, and the USA made formula feels consistent, clean and professionally prepared.

The exact supplement blend is proprietary, so precise customization is limited. You will also need separate grain spawn, and larger projects may require multiple bags to fill big tubs or beds.

For growers who want reliable results without pasteurizing manure at home, the Boomr Bag is a practical upgrade. It saves time, simplifies spawn to bulk, and delivers a trusted foundation for productive grows.

Specifications

Brand: North Spore, Style: Sterile substrate in filter patch bag.

Size: 5 pounds, 80 ounce count, 4.75 liters volume.

Material: Composted horse manure, coco coir plus substrate supplements, hydrated to field capacity.

Best for: Monotubs, filter bags, trays, Martha setups and outdoor beds for dung loving species.

Recommended use: Mix 1 colonized grain spawn bag with 2 to 3 Boomr Bags.

How to Use

Mix one fully colonized grain spawn bag with two to three Boomr Bags for reliable colonization. Break up the spawn, blend evenly, then incubate in your monotub, bag or tray.

Maintain proper humidity and fresh air exchange for your chosen setup. For outdoor beds, layer the mix in a shaded spot and keep it moist but not waterlogged.

This substrate is best for dung loving species. If you are new to bulk growing, start with one tub to learn the process before scaling up.

10
Prime

Out-Grow Pasteurized Manure Mushroom Substrate 25

Out-Grow
In Stock
9.5 /10
FungiPop Score
FungiPop Score is calculated from a base score plus a scaling bonus tied to the product's own Amazon star rating (same formula for every product, capped at 9.9/10). It is not influenced by any manufacturer or affiliate relationship. Learn more ›
This is a 25 lb manure-based mushroom substrate from Out-Grow, divided into five 5 lb bags for bulk cultivation. It comes fully pasteurized and pH balanced, making it best for growers who want a nutritious, ready to use substrate without prep work.
Pros & Cons

Pros

  • Arrives pasteurized and pH balanced for immediate use
  • Generous 25 lb bulk quantity split into manageable 5 lb bags
  • Manure based nutrition supports vigorous, healthy mushroom growth
  • Well suited for bulk methods like monotubs and trays

Cons

  • Manure based substrate has a natural earthy odor during handling
  • Bulk 25 lb size requires cool, dry storage space to maintain freshness
  • Beginners with small countertop kits may find the volume more than needed
Detailed Review

The Out-Grow Pasteurized Manure Based Mushroom Substrate is a 25 lb bulk substrate designed for serious mushroom cultivators. It is divided into five sealed 5 lb bags, making it ideal for monotubs, trays and larger bulk grows.

Its biggest advantage is convenience, since it arrives fully pasteurized and pH balanced. That means you can spawn directly without cooking, hydrating or buffering, which saves hours of prep and helps support fast, healthy colonization.

The manure based formula is rich, consistent and properly textured for mycelium growth. The smaller 5 lb bags are easy to store, open as needed and keep unused substrate fresher than a single large bag.

There are a few tradeoffs to consider. The manure base has a natural farm odor, and the full 25 lb quantity needs adequate storage space. Very small scale growers may prefer a smaller starter bag.

Overall, this is a practical, high performance bulk substrate for growers who want reliable nutrition without DIY pasteurization. If you run bulk tubs and value consistency and ease of use, it is an excellent choice.

Specifications

Brand: Out-Grow, Style: Modern, Total Weight: 25 pounds in five 5 pound bags.

Base Material: Pasteurized manure based mushroom substrate, pH balanced and ready to use.

Unit Count: 400 ounces, UPC: 616576242937, Category: Fertilizers and Plant Food.

What to Know Before You Choose Manure or Masters Mix

Manure blends feed dung loving varieties with composted nutrition, while Masters Mix feeds wood loving varieties with oak and soy hulls. Your choice should follow your species first, then your available equipment, time and tolerance for odor, mess and sterilization steps.

Nutrient Source and Species Match

Manure provides nitrogen rich, composted nutrition that dung colonizers love. Options like Pasteurized Horse Manure and Straw Mushroom combine horse manure with straw, vermiculite, worm castings, gypsum and coco coir for a diverse diet, while North Spore ‘Boomr Bag’ Sterile Mushroom Bulk uses composted horse manure plus coco coir and supplements for vigorous colonization in monotubs, bags or outdoor beds.

Masters Mix takes a different path with 50 percent oak and 50 percent soy hull pellets for wood lovers such as oyster, shiitake and lion’s mane. Fast Fruiting Pellets, aka Masters Mix offers that classic ratio in pellet form for rapid mycelium spread and heavy fruiting, which makes it ideal if you follow a routine like our budget friendly oyster grow bag method or grow in supplemented sawdust bags.

Moisture Retention, Aeration and pH Balance

Great bulk substrate holds water without pooling and stays airy enough for mycelium to breathe. Boomer Shroomer Dry Bulk Substrate for Mushroom uses coco coir for water holding, vermiculite for air pockets and gypsum for pH stability, a balanced CVG approach that suits spawn to bulk transfers in trays, tubs or filter bags after proper bucket pasteurization.

Ready to use blends manage this balance for you. Myco Labs Premium Bulk Mushroom Substrate Mix emphasizes field capacity hydration and a calcium mineral blend for a favorable pH, while 5 LBS Black Coco Mushroom Substrate relies on coco coir, vermiculite and gypsum for clean moisture control. If you run a humid fruiting chamber, pair your pick with the airflow ideas in our monotub liner versus Martha tent comparison.

Prep Level: Dry Mix Versus Ready to Use

Your comfort with prep should guide your purchase. Boomer Shroomer Dry Bulk Substrate for Mushroom arrives dry and hydrates with boiling water in a 5 gallon bucket, then rests for pasteurization to reach field capacity. That format stores well, ships light and yields enough hydrated material for two full monotub grows, which suits growers who enjoy hands on preparation.

If you want to open and spawn immediately, choose pre hydrated and pasteurized or sterile bags. 5 LBS Coco Mushroom Substrate with Added Cow arrives pre hydrated in a 0.2 micron filter bag for monotub filling or in bag spawning, and Pasteurized Horse Manure Based Mushroom Bulk comes in five sealed 1 pound bags with filters for gas exchange. These formats reduce measuring and pasteurizing steps and help beginners avoid moisture errors.

Volume, Spawn Ratio and Workflow Fit

Match bag size to your spawn volume and fruiting space. Small tent growers often do well with 5 pound bags like 5 LBS Coco Mushroom Substrate with Added Cow or Pasteurized Horse Manure and Straw Mushroom, while dedicated monotub growers benefit from 10 LBS Coco Mushroom Substrate with Added Cow for deeper substrate depth and stronger second flushes. Larger projects can use Pasteurized Manure Based Mushroom Substrate in 25 pound bulk format with five separate bags.

Pay attention to recommended spawn ratios and vessel compatibility. North Spore ‘Boomr Bag’ Sterile Mushroom Bulk suggests mixing one colonized grain bag with two to three Boomr Bags for reliable colonization, a higher inoculation rate that supports cleaner runs. For shiitake logs or supplemented sawdust blocks, review our low cost shiitake substrate picks to align pellet volume, bag size and sterilization capacity before you order.

Final Thoughts

For wood lovers and high yield oyster or shiitake grows choose Fast Fruiting Pellets, aka Masters Mix, while for dung lovers and low prep monotubs choose North Spore ‘Boomr Bag’ Sterile Mushroom Bulk.

Frequently Asked Questions

Is manure substrate better than Masters Mix for oyster mushrooms?

For most oyster varieties in 2026, Masters Mix is the stronger choice because oysters are wood lovers that respond to oak and soy nutrition. Fast Fruiting Pellets, aka Masters Mix is formulated for that purpose with uniform pellets that hydrate evenly and colonize quickly. Manure can work for some strains, but expect denser growth and larger flushes from a proper wood based supplement.

Do I need to sterilize Masters Mix and pasteurize manure?

Yes, in general Masters Mix benefits from sterilization because soy hulls are highly nutritious and prone to contamination, while many manure and CVG blends perform well with pasteurization that preserves beneficial microbes. Dry products like Boomer Shroomer Dry Bulk Substrate for Mushroom use hot water bucket pasteurization, whereas sterile options like North Spore ‘Boomr Bag’ Sterile Mushroom Bulk arrive ready to inoculate. Always follow the maker directions for your specific product and setup.

Can I use cow manure coco substrate in a monotub?

Yes, cow manure coco blends are popular for monotubs because they combine nutrition with excellent moisture control. Both 5 LBS Coco Mushroom Substrate with Added Cow and 10 LBS Coco Mushroom Substrate with Added Cow are pre hydrated for direct monotub filling or for spawning grain directly in the bag. Keep depth even, maintain gas exchange and avoid over misting to support full colonization and healthy pin sets.

How much bulk substrate do I need per bag of grain spawn?

A common home grow target in 2026 is one part colonized grain to two to three parts bulk substrate by volume. For example, one grain bag pairs well with two to three Boomr Bags, or with five to ten pounds of CVG or manure blend depending on tub size. If you are scaling spawn production, our spawn bag comparison for growers and lion’s mane substrate ideas for Martha tents can help you plan ratios and fruiting space.

Browse more picks in our Substrate, CVG & Bulk Amendments category, or see our related guide on Lions Mane Substrate for Martha Tent: How to Choose 2026.

These picks are not ideal if you are growing a species that fruits directly on grain spawn without a bulk substrate step; check your species and method before buying bulk substrate.