‘Boomr Bag’ (5 lb) Manure-Based Sterile Mushroom Bulk Substrate | Maximum Yield Formula | Made in USA | Grow Dung-Loving Mushrooms | North Spore
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This item is eligible for return within 30 days of receipt
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Availability:
In Stock.
Arrives
Mar 31 – Apr 2
Features
- INCREASE YOUR YIELD: Our best-selling Boomr Bag is a sterile manure-based bulk mushroom substrate formulated by mycologists to increase the yield of your grow.
- PREMIUM MANURE BLEND: It features a proprietary blend of composted horse manure, coco coir, and several quality substrate supplements (although we keep the exact blend a secret!)
- TRUSTED BY GROWERS: Over several years, Boomr Bag has been perfected for dung-loving mushroom species and is widely-trusted by mushroom growers. Note: Substrate is hydrated to field capacity.
- FOR EVERY TYPE OF GROWER: Use Boomr Bag in monotubs, filter bags, and outdoor beds. Or, grow mushrooms from the bag or tray in a humidity-controlled grow room or Martha set up.
- SPAWN TO BULK RATIO: We recommended mixing 1 colonized grain spawn bag with 2-3 Boomr Bags. (Higher inoculation rates may improve your success.)
- STORAGE: Boomr Bags should be stored at room temperature out of direct sunlight. No refrigeration is necessary. They can also be stored for several months before use.
- BEST PRACTICES: We recommend clean hands, latex or nitrile gloves, and sterile technique when using Boomr Bag to reduce the introduction of contaminants. It is also best practice to wait a minimum of 1 week after arrival before using sterile substrates to ensure they were not compromised during transit.
Brand: North Spore
Style: Sterile substrate
Item Weight: 5 Pounds
UPC:
Global Trade Identification Number: 31
Brand Name: North Spore
UPC: 851555008931
Global Trade Identification Number: 31
Manufacturer: North Spore
Unit Count: 80.0 Ounce
Style Name: Sterile substrate
Item Weight: 5 Pounds
Volume: 4.75 Liters
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Mar 31 – Apr 2
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Good stuff all I use
Reviewed in the United States on February 11, 2026 by Nick
I switched to boomr bags after being unsatisfied with other pre-pasteurized substrates and mixing and sterilizing my own. It's not cheap, but the end result is superior. Keep bag for at least a week before using to check for contam. North Spore will replace for free any contaminated bags if you contact them. I've never seen a contaminated bag even after over 20 orders, but I have had to get north spore to replace a grain bag which they did hassle-free. Just take a pic of the contaminated and the lot number sticker on bag and email them. For anyone saying this substrate doesn't work for manure lovers, I'd say you just don't know how to grow mushrooms. A lot of people contaminate batches themselves without realizing it. The bag may come too wet or dry. Too dry, just spray with distilled water during mixing with spawn in sterilized room. Too wet (you can tell if water separates from substrate and you can see liquid in bag) let it dry out by spraying breather patch with alcohol and unfolding bag a little and let sit a few days. Always spray breather port with alcohol before handling or moving it from box. Airborne bacteria can get pulled into bag from patch.
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Reviewed in the United States on January 21, 2023 by Travis Lee
I got some chonky mushrooms with my Boomr Bag. If you're a newbie, just know that you have to germinate your spores in an agar plate, or BRF jar first.
Reviewed in the United States on December 14, 2025 by Chris
Original order was for 2 dung lovers bags, waited a few weeks and saw that one was contaminated. Contacted North Spore directly with my Amazon order # and they immediately sent me a replacement. Great customer service response and communication. Ordered 3 more dung lovers bags due to my needs and currently waiting to see if they along with the replacement crop up with contamination. Great response from North Spore otherwise.
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Reviewed in the United States on June 10, 2025 by Amazon Customer
Always had luck in the past, good and clean. This time it was awful
Reviewed in the United States on February 24, 2026 by james moxley james moxley
This sat for weeks before use, no issues with leaks or any kind of bad stuff growing in it. Moisture content was perfect even after sitting so long. I added this to two separate bags of mycelium that was growing in other substrate bags, allowed a few days to mix and colonize a bit more, then dumped into growing trays that had lids and air vents. Mycelium fully colonized within a week, thick white carpet of fuzz was gorgeous and happy. Moisture content stayed perfect throughout growing cycle. Absolutely no sign of contamination or mold or anything bad even after several months. Would recommend and buy again
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Reviewed in the United States on October 24, 2023 by Svz
North spore does not disappoint! Great products. I keep ordering. Never any issues.
Reviewed in the United States on October 10, 2025 by Christina H
This is the 2nd manure based substrate I've tried, the 1st I've had good results from. When I opened the box, comparatively, it looked like mulch. I actually thought they sent wood lovers by mistake lol I'm no expert, but again compared to my trusted brand, this one looks like it's at least 50% coco cior and the other brand looked like it was only 5%. It probably helps with aeration, and it didn't take as long to break up. Oh, and there was a rock over an inch long.... Will overlook that(minus a star tho) and update with how it performs.. I hope their equipment is OK after that went through lol An update.. 2 things. 1. It was extremely hydrated to the point that I had to carefully take the lid off early with something nearby to pour the water in before giant droplets started raining down.. Minus another star. 2. The cleanup was.. Less gross with less poo lol Will give 1 more try with a different one I'm more familiar with just bc of the easy clean up to see if there's a noticeable difference in quality. I do not recommend for things vulnerable to wet spots. Update: They must read these, the next batch was significantly darker lol. I mean, yay for this time(I hope, still too early), but it also tells me the product isn't consistent. Unless I see 3 nice tasty flushes this time, I'll stick to the other comparatively priced one. Final update: Did not see 3 flushes out of something I've seen have more. Still not a high enough poo to coco coir ratio methinks. I'm not an expert, but I'm not sure why their kits have coco coir to put on top of this, it seems to have enough lol
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Reviewed in the United States on May 29, 2025 by Placeholder Placeholder