Before You Buy FAQ

This page is designed to answer FAQs about the product before you purchase. If you have troubleshooting questions after purchase, please visit our troubleshooting FAQ.

  • Mycology is the branch of biology concerned with the study of fungi.
  • Mycologists are people who study or work with fungi.
  • Mushrooms are the fruiting body of a fungus.
  • Fungi are not actually plants. They don’t photosynthesize, they don’t process carbon dioxide. Fungi breathe air and let off carbon dioxide – just like people!
  • Mycelium is the vegetative part of a fungus. It’s basically like the “root system” before a mushroom grows. When growing mushrooms, you want a nice strong spread of mycelium first. Mushrooms grow when the mycelium has colonized (spread) around a substrate, digested nutrients, and starts to move into a reproductive stage. 
  • A spore is a single-celled reproductive unit of a mushroom. These are kind of like seeds. Mushrooms generally drop spores once they’re fully mature, and those spores germinate together and under the right conditions will grow mycelium and more mushrooms.
  • Liquid culture is basically a clone of a mushroom – it’s early stage mycelium, ready to inject into a grow medium and immediately start spreading. Liquid culture is usually made from the best performing mushrooms, to continue their genetic spread. 
  • Fruiting or fruits in the context of mushroom growing is referring to the actual mushroom bodies, rather than the mycelium.
  • Substrate is a combination of grain and soil which provide nutrients to help mycelium grow.
  • A varietal is what specific variation of mushroom you’re growing – think of it like “strains” in cannabis. Different varietals could be Penis Envy, Albino Burma, or Steel Magnolia, for example.

Our Shrüm Grow Bag & Genetics are designed and optimized for cubensis mushrooms. These are popularly known as magic mushrooms. We sell our products for novelty and research – we do not advise consumption. Consuming the end product could result in psychedelic hallucinations and experiences.

Our products are shipped in plain, unmarked packages of brown or white. There is nothing on the outside of the box to indicate what is inside. Our shipping label says in small print that it is from “Advanced Mycology”. We ship via USPS for small orders. Larger orders may be shipped via FedEx.

With exception of new releases, which may have a notification of a “date to ship”…

Our facility should ship product within 1-2 business days (not including weekends). We ship via USPS ground, not expedited shipping. You will receive an email update with your tracking number (and also one with your order number – if you didn’t receive one check your Junk folder). It can take USPS up to 24 hours to update that after receiving the package. If we are having significant delays at our facility for any reason we will send an email. You can also email inquiring about the status of your package at

You can order liquid culture (which is much better than using spores) directly from us on products marked “LC”. We also have some partners with approved genetics you can use, you can learn more on our Genetics page. We do not guarantee any results if you use a different brand or spores, and our ability to troubleshoot or replace failures will be limited.

Growing mushrooms is generally hard, time consuming, labor intensive & expensive. 

When using traditional methods like tubs and grain jars and all the related items you need to get started, the investment is high but the possibility of failure is even higher. 

You shouldn’t have to be an automotive engineer to drive a car, or a computer scientist to use a computer! You shouldn’t have to be a mycologist to grow mushrooms.

Our team here at Shrum spent nearly 2 years developing our Shrüm All-in-One Grow Bag before releasing to market in June of 2022, and we’ve been perfecting our bags ever since. We have spent our time since launch improving the nutrient blends, the physical bag itself, our instructions and your expectations. 

You don’t need tubs, tents, or a dedicated grow space. You don’t need special lights, special temperature or humidity sensors, or a clean room. You can grow mushrooms in your own home – in a closet, on a coffee table, on a bookshelf. 

We wanted to make an affordable and radically simple solution for you to safely and simply grow your own mushrooms.

There are 5 key things about our grow bags:

  • Our filter strips
  • Our substrate blend
  • Our patent-pending microwave tech
  • Our shelf life
  • Our genetics guarantee

Let’s dive into each one:

Our Filter Strips!

The radical new tech featured in our product (and unique in the market) is our filter strips. Mushrooms are just like us – they breathe air, and give off CO2! Our filter strips are 0.2 micron equivalent, and they allow air to enter and C02 to leave. Your mushrooms can breathe and grow right inside the bag – safely until harvest! 

There are other grow bags out there – but they all have a problem. The mushrooms can’t breathe. A bag with only a filter patch at the top doesn’t properly let go of C02 or let in fresh oxygen. In order to fruit, you need to cut their bag open. 

Ideally for them, you’d move their block of colonized substrate into a tub or tent (that’s no longer simple – that requires more equipment and very careful clean work!). Or you cut the bag open and hope your harvest arrives before the mold does. Either way – the moment you cut that bag open before any mushrooms have grown: you risk your entire harvest. 

Our Substrate Blend!

Your substrate is the medium your mycelium grows in that provides all the nutrition to develop mushrooms that thrive.

Our bag contains: millet, coco coir, vermiculite, gypsum, worm castings, crushed oyster shells and water. We recently added MycoBoost to the mix as well, for faster and better performance! Our ingredients are carefully sourced and prepared to maximize bio-availability. 

We’ve tested dozens of combinations of substrate to bring the best results to our customers. We spent nearly 2 years doing this before launch, and continue to perfect it since launching in June 2022. We have a lot of experience with this!

One of the big keys is we don’t use manure in our substrate – in the interest of a consumer product, we wanted to make sure we produce a substrate that can sustain our mushrooms and NOT stink up your home!

Our Patent-Pending Microwave Tech!

Our bags come fully sterilized and vacuum sealed, which means they’re ready to go when you purchase them, but as we did research on bags we discovered that microwaving bags was improving their success, their yields, and the environment for the mycelium! This completely optional step helps your peace of mind too!

Just take your bag out of the vacuum seal bag first. Microwave for ninety seconds. Don’t go longer – it could pop! Wait for it to cool down (it can be warm but not hot when you inoculate. We recommend waiting an hour to be sure). 

Then inoculate your genetics! 

Don’t have a microwave? Skip it! 

Shelf Life!

Mycology products fail for the same reason other fresh food gets ruined: bacteria and mold.

Spores of mold and endospores of bacteria can survive the extreme heat of sterilization and pasteurization. Growing mushrooms is a race against time from the point of sterilization, to inoculate your mycelium and let the colony develop before competing mold and bacteria colonies develop to claim your nutrient rich environment as their territory.

Mycology is a war, and we must win; we do not want to grow bacteria and mold – mushrooms will not grow in areas colonized by bacteria and mold.

We’ve developed a sterilization technique that solves this problem. We also vacuum seal our bags immediately after sterilization. The absence of oxygen inhibits bacteria and mold, preserving the grow bag in the same state it was in immediately after sterilization. Our microwave tech with this step really solidifies this further. 

Between our sterilization, our vacuum sealing (which also preserves needed moisture) and our microwave step, our bags MAY have a practically unlimited shelf-life. We guarantee our grow bags for a year from production, but as of February 2024 we have grow bags that are 2 years old and are still free from contamination and are growing mushrooms!

Our genetics guarantee!

Use our preferred Artisan Mushroom Genetics offered by Shrüm with our Grow Bags to ensure a guaranteed success experience! Our preferred genetics are designed to grow in these bags – and if you experience a failure, we troubleshoot to make sure you followed our directions and then replace the product! 

Your bag comes to you completed sterilized and vacuum sealed, which means it’s ready to go as soon as you take it out of the vacuum sealed packaging. However, we have a (patent pending) process to be even more careful and maximize performance. 

You can microwave your grow bag!

No – you don’t have to. You can skip this step. But we find that the extra step can improve our already high success rate, and maximize the environment for the mycelium! 

  • You take your bag out of the vacuum seal bag first.
  • Microwave for ninety seconds.  Don’t go longer – it could pop!
  • Wait for it to cool down (it can be warm but not hot when you inoculate. We recommend waiting an hour to be sure). 
  • Then inoculate your genetics just like normal! 

Don’t have a microwave? Skip it! 

This is not a cost-efficient option for bulk growers. Our focus is on simplicity, not yield, and for a large-scale bulk grow we still recommend using grain bags & tubs. Reach out to if you would like to buy bulk quantities of our preferred liquid culture.

  • You control what you grow, no questions about quality.
  • You do so in the privacy and comfort (and safety) of your own home.
  • You get to experience the entire process from scratch.
  • You can get multiple harvests from a single bag.
  • It’s really amazing to do!

Our Shrüm V3 Mini bag (which weighs 12 ounces) is the fastest product on the market! It can fruit in as little as 4 weeks! We usually see fruiting in 4-6 weeks.

Our Shrüm V2 grow bag is 1.8 lbs and typically fruits in 6-10 weeks.

Please note, there are multiple factors that can influence grow time, most importantly the genetics you choose and the temperatures you grow at. Colder temperatures can stall mushrooms. Some varietals do grow slower than others.

We do not recommend spores with our grow bags, but if you decide to use spores, please note grow times will be roughly 2 weeks more.


Our Shrüm Grow Bags are vacuum sealed to preserve moisture & freshness.

We guarantee our grow bags free of contaminants for up to a year after sterilization (if they’ve been kept vacuum sealed and unused). If you buy our product and find any indications of contamination or an unpleasant smell upon opening the vacuum seal, please contact us for a replacement.

Our preferred genetics are live liquid culture. They should never be frozen or heated. With refrigeration, they’ll work great for a year. At room temperature, they’re good for about three months.

We have some information in our Troubleshooting FAQ about how to spot when genetics have gone bad.

Harvest size can depend on many factors including genetics & environment (a drier climate may dry out the bag a little and yield slightly less – mushrooms are 90% water!).

Our Shrüm V3 Mini bag yields an average of 5-10 grams of dry fruit in a first harvest. We have seen as much as 18 grams from a single bag (multiple harvests).

Our Shrüm V2 grow bag yields an average of 10-20 grams of dry fruit in a first harvest. We have seen as much as 35 grams from a single bag (multiple harvests).

Our grow bags contain millet, substrate and water. 

Our genetics are liquid cultures which contain very early stage mycelium, which is not illegal in any state or federally. There is no psilocybin in liquid culture.

Please note: the product that you may grow may have different legal status depending on your location. 

We sell our products for novelty and research – do not consume. Consuming the end product could result in psychedelic hallucinations and experiences.

We designed this product to be radically simple. We include an instruction booklet which contains all directions for growing, including ideal environment recommendations. 

We recommend growing at temperatures in the mid-70s. They grow best between 70-80 degrees – much cooler and they’ll stall out, much warmer and bacteria might outpace them.

Do not use special grow lamps. Mushrooms do not photosynthesize and do not need light. They will grow in the direction of light, but indirect and non-intense light from above will help grow mushrooms straight up.

Humidity is great! The bag comes hydrated and you don’t need to hydrate it, but super dry environments can dry it out a bit, so if you have a humidifier it doesn’t hurt to have it nearby.

Airflow is a key part of fruiting though! If you place your grow bag in a closet, it needs movement and fresh air regularly to make sure the CO2 is moving out of the bag, and air inside. During the fruiting stage, we highly recommend keeping the bag somewhere in the open or near a fan, where air can freely flow around it.

We do not do refunds, however we will happily troubleshoot and replace a problem product if the fault was ours. We are committed to standing by our product and will do everything we can to make sure your experience with us is positive.

If you open your grow bag to find mold or contamination prior to inoculation, or an unpleasant odor, please contact us at for immediate replacement. 

If you have a store that had a batch with contamination issues, no vacuum seal or the vacuum seal is swollen, please contact us at for replacement.

Note: we do not require you return product in order to have it replaced. You can simply send us photos of the problem and we’ll send out replacements.

If your bag has been inoculated and fails to perform, we can replace it under certain circumstances. 

If your bag fails to produce any mushrooms in a reasonable amount of time using our grow bag and our liquid culture, following all of our directions and troubleshooting for obvious issues that did not originate with us, we will replace both products. 

If your bag fails using another company’s genetics, we will troubleshoot for issues and provide what support we can, which may include replacement (with our genetics) depending on our existing knowledge of the other brands. We can offer significant discounts to try again with our grow bag and our culture if we can’t replace it. 

We cannot replace a bag which you have opened. Do not add water, do not inoculate a second syringe, do not open the bag before harvesting for any reason, as it voids our ability to replace it. 

We also have a Troubleshooting FAQ for customers after purchase, which you can find at this link.

We are happy to assist you! Email with your inquiry and we’ll get back to you quickly with our wholesale portal and answers to your questions!