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North Spore

North Spore 'Boomr Bag' Sterile Mushroom Bulk Substrate, Manure-Based, 5 lb

  • Based on 1,241 reviews
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Availability: In Stock.
Fulfilled by North Spore Mushroom Company
Arrives Aug 31 – Sep 4
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Size: 1 Pack


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.)

Description

Our best-selling Boomr Bag is a sterile manure-based bulk mushroom substrate formulated by mycologists to maximize your mushroom yield. Boomr bag was developed for growing edible and medicinal dung-loving mushroom species. (If growing hardwood-loving species, use our Wood Lovr sterile substrate instead.) Boomr Bag features a proprietary blend of composted horse manure, coco coir, and several quality substrate supplements. Bags are hydrated to field capacity. Boomr Bag was formulated by expert mycologists in Maine, USA to increase the yield of your grow. The formula has been perfected over the years for dung-loving mushroom species. Boomr Bags are made in a vertically-integrated facility and sterilized in a commercial-grade autoclave. Sterility is verified using biological indicators and temperature sensors. North Spore was launched in 2014 by a mycologist, an organic farmer, and a photojournalist -- three college friends brought together through their shared love of the mycological world. North Spore provides everything one needs to grow mushrooms, from the beginner to the expert. From Spray & Grow Kits to growing chambers, sterile substrates, lab supplies, and more. We also offer medicinals made with the highest quality fruiting body extracts.

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


Number of Packs: 1


Unit Count: 80 Ounce


Manufacturer: North Spore


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: Aug 31 – Sep 4

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.

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Top Amazon Reviews

    • Great product
Size: 1 Pack
Works great. 1st time doing this and it’s been a breeze
Reviewed in the United States on July 29, 2026 by Clifton castle
    • Best pre-pasteurized substrate I've found.
Size: 1 Pack
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. ... show more
Reviewed in the United States on January 21, 2023 by Travis Lee
    • North Spore Rules!!
Size: 1 Pack
Everything from north spore is top notch. This is no exception.
Reviewed in the United States on August 14, 2026 by Noah Reynolds
    • Very disappointed
Size: 1 Pack
Thought this was suppose to be one of the best substrates out there to use. It takes time to grow and I’m using for personal use so I only do a few grow bags at a time. With in 6 months when I went to use I noticed bugs in my substrate. Now I kept indoors, I folded and clipped the bag tight when not in use and it was stored in the original bag, box in a closed cabinet. When I looked further I saw it was infested with gnat bugs and I felt like it was no longer usable for indoor use. It was over the return time so it was a complete waste of money on my end. If you’re using for a large grow at one time then it might be better but not in my case. I already disposed of it and did not take pictures because when I noticed this I just wanted to get it out of the house. ... show more
Reviewed in the United States on October 30, 2024 by Jennifer
    • Wait a few weeks before going to bulk.
Size: 1 Pack
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. ... show more
Reviewed in the United States on June 10, 2025 by Amazon Customer
    • Very Good
Size: 8 Pack
The best substrate I have ever used, good yield and large fruits.
Reviewed in the United States on August 21, 2026 by RODNEY J.
    • quality product
Size: 1 Pack
quality product
Reviewed in the United States on July 27, 2026 by Rick Clute
    • First impressions(and 2nd, and 3rd)
Size: 1 Pack
Review Image by Placeholder
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 ... show more
Reviewed in the United States on May 29, 2025 by Placeholder

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