XL Magic Mushroom Grow Kit

Enough shrooms for more than enough trips

These XL shroom grow kits yield large quantities of mushrooms that you can use yourself. Please keep in mind that due to the bigger boxes the mycelium will need about 5 weeks to grow its first flush. The 2100cc set gets you up to 800 grams of shrooms! 10 to 15 grams is recommended per trip, which means that you will have plenty left over.

Important to know

Keep the cardboard boxes the grow kits came in with the bags or make a picture of the sticker on the outside. This contains the batch number. This number is important and counts as a receipt for our supplier if anything goes wrong with the box. They will need it to be able to send a replacement. Without the batch number we will be unable to replace or refund the box. This counts only for boxes that have no growth after the 5 weeks mark. Boxes that have arrived broken during shipping will be replaced. Boxes sent anywhere outside of Europe will not be replaced due to the longer shipping time. This is at your own risk.

What is in an XL grow kit?

All our grow kits are all-in-one sets. This means that they contain everything you need to grow magic mushrooms: substrate and growing bags. You can also grow a wide variety of mushrooms, some of which have different care needs. For example, the Cambodian XL is less sensitive to infection, which poses less of a risk of a failed harvest than other species.

The purchase and sale of magic mushrooms is prohibited in the Netherlands, but grow sets are entirely legal to buy. Growing at home is also allowed. Do you have questions? Feel free to contact us.

Check here the manual

Which strains are available in XL?

Our XL range is built around Psilocybe cubensis, the most widely cultivated psilocybin mushroom species. Each strain has its own character, effects profile and difficulty level. The strain finder walks you through a few targeted questions and gives you a concrete recommendation.

What Is an XL Grow Kit?

A grow kit is a ready-to-use cultivation set for psilocybin mushrooms. The mycelium, the white fungal network that produces the fruiting bodies, has already been fully colonised into the substrate before the kit reaches you. Your job is to provide the right conditions: warmth, humidity and fresh air. The kit does the rest.

An XL kit is defined by its volume. While small kits typically contain 250 to 500cc of colonised substrate, and medium kits land around 1200cc, XL kits start at 2100cc and some go considerably beyond that. More volume means more mycelium, and more mycelium means heavier, more abundant flushes. That is the essential difference.

A larger block also has more inherent resilience. If conditions slip slightly, a well-colonised XL block will recover more readily than a smaller one. At the same time, more substrate is more potential food for unwanted moulds and bacteria, so hygiene becomes correspondingly more important. XL kits reward experience and attention to detail.

XL vs Medium and Small: When to Choose What

This is the question we hear most often, and the honest answer depends on your situation.

A small grow kit is the right starting point for a first-time grower. Lower stakes if something goes wrong, less substrate to manage, lower cost. A failed first attempt with a small kit is an inexpensive lesson. A successful one gives you exactly the knowledge you need to scale up.

A medium kit is the most versatile option. Big enough for meaningful harvests, manageable enough for someone who has grown once or twice. For most people, medium is the natural next step after small.

The XL kit is for growers who know what they are doing and want to maximise what they harvest per cycle. A well-managed medium kit can yield three to five grams of dried mushrooms per flush. A well-managed XL kit running the same strain under the same conditions can produce two to three times that. Per flush, across multiple flushes, the difference adds up significantly.

There is also a practical angle: anyone who grows regularly and wants to store harvests for personal use over a longer period will find that one good XL cycle provides more than enough. That changes the cost calculation compared to running multiple smaller kits sequentially.

How an XL Grow Kit Works in Practice

The process mirrors smaller kits but demands a little more precision at each step.

Store the kit in the refrigerator, sealed, if you are not starting immediately. Once you are ready, remove the lid from the tray, fill the tray with clean water and allow the mycelium to soak for five to twelve hours. Drain the water. Place the tray inside the included grow bag or a clean humidity tent. Mist the inside of the bag twice daily to maintain high humidity, but never spray directly onto the mycelium surface itself.

Pins typically appear within five to fourteen days of the first soak, depending on strain and ambient temperature. The ideal cultivation temperature is 23 to 26 degrees Celsius. Temperatures below 20 degrees slow growth substantially. Temperatures above 28 degrees increase contamination risk.

Harvest when the veils beneath the caps are still intact or just beginning to tear. At this point the mushrooms contain the highest concentration of active compounds and spore release is still minimal. After the first flush, soak the block again to trigger a second flush, and repeat for a third or fourth if the block remains uncontaminated and productive. XL kits routinely deliver three solid flushes before the mycelium is exhausted.

Hygiene: the Single Most Important Variable

Fifteen years of grower questions have produced a clear pattern. Most failed grows share one cause. Not a defective kit. Not a difficult strain. Not an error in technique. Insufficient attention to hygiene.

Green or black patches on your substrate are contamination. Once they appear, the kit is done. There is no rescue protocol. This is why: always work with clean hands or disposable gloves. Work in a clean space, away from open windows or fans that move air around. Mist the bag interior, not the block directly. Never open the bag longer than necessary.

With an XL kit, the stakes are higher on both sides. A successful XL kit is very rewarding. A contaminated one is a larger loss. The margin for casual hygiene is smaller. Take it seriously from day one, not after the first problem appears.

Storage and Optimal Growing Conditions

An unopened XL kit stores well in the refrigerator at 2 to 4 degrees Celsius, kept in its original sealed packaging. Under these conditions the mycelium remains viable for several months. Open the kit only when you are ready to begin, because once the first soak starts, the process should continue without interruption.

Once growing, the kit needs daily attention for at least the first two weeks: checking for pins, misting the bag, monitoring for contamination. It is not demanding in terms of time, perhaps five minutes twice a day, but it requires consistency.

For drying the harvest, a food dehydrator set below 35 degrees Celsius is the most reliable method. Air drying on paper works but takes longer and carries more mould risk in humid conditions. Properly dried mushrooms store in an airtight glass jar, in a cool, dark place, for up to twelve months without significant quality loss. Vacuum containers extend this further for those who want maximum shelf life.

Legal Status of Magic Mushroom Grow Kits

In the Netherlands, grow kits for psilocybin mushrooms are legal to purchase and possess. The Opium Act prohibits dried and fresh mushrooms, but the cultivation of mushrooms for personal use occupies a legal grey area that is not prosecuted in practice. We sell the kits; how you use them is your responsibility.

The situation differs in other EU countries. Belgium, Germany and France have stricter frameworks. Importing psilocybin-containing mushrooms or cultivation materials is illegal in some countries. If you live outside the Netherlands, check the legislation in your country before ordering. We deliver across Europe, but the recipient carries responsibility for compliance with local rules.

Why Avalon for Your XL Grow Kit?

We have been working with mushroom growers at all experience levels since 2009. That track record has given us a precise picture of where quality differences show up most clearly: mycelium density, substrate moisture balance and the consistency of contamination-free production. The XL kits in our range are selected on all three of these points.

We do not stock kits we would not use ourselves. If a batch does not meet our standards, it does not go on sale. That sounds basic. In practice, it means our return rate from contaminated kits is considerably lower than industry average, because we catch problems before they reach customers.

Our full range covers over 1500 products, including a well-stocked section of growing aids: thermometers, hygrometers, drying racks, spore materials and more. Everything you need for a successful grow is available in one place. For growing techniques, strain profiles and troubleshooting, our blog has you covered.

Drying and Storing Your Harvest

A good harvest starts at picking, but quality is determined by drying. Fresh mushrooms are approximately 90 percent water. If you do not dry them quickly and thoroughly, degradation begins within hours of harvest. A food dehydrator set below 35 degrees Celsius is the most reliable method. Higher temperatures damage psilocybin and psilocin, the active compounds you are specifically trying to preserve.

No dehydrator? The next best option is a fan at room temperature combined with silica strips to keep ambient humidity low. Spread the mushrooms on a rack or sheet of paper and allow at least 24 hours for full drying. They are ready when they snap and crumble like crackers, not when they bend. Flexible mushrooms still contain too much moisture and will mould in the jar.

Store in an airtight glass jar in a cool, dark place. Adding a small silica strip inside the jar provides an extra layer of protection against residual moisture. Properly dried and stored, good mushrooms hold their quality for up to a year, sometimes longer, without meaningful potency loss.

Common Mistakes With XL Grow Kits

Not soaking long enough at the start is a classic error. The soak rehydrates the outer surface of the mycelium block, which dries slightly during transport and storage. Cutting it short leaves the outer layer too dry, slowing the first flush or reducing its weight. Keep to the full five to twelve hours.

Over-misting is the opposite mistake. Some growers assume more humidity is always better and mist five times a day instead of two. That leads to water pooling on the substrate surface, increasing the risk of bacterial contamination. Twice daily into the bag interior, not onto the block itself, is correct and sufficient.

Harvesting too early is tempting but wasteful. Underdeveloped mushrooms contain fewer active compounds per gram than fully matured ones picked just before the veil breaks. Wait until the cap has fully expanded but the membrane beneath it is still intact. That timing gives the best ratio of weight to potency.

Rushing the second flush is another common misstep. Give the block a full soak of eight to twelve hours after the first harvest before expecting pins to appear again. Patience between flushes pays back in consistent, productive cycles.

Pairing XL Kits With Growing Accessories

A good XL kit is a strong foundation, but the right growing accessories make the difference between an average and an excellent grow. A thermometer and hygrometer are the two most practical additions. Without measuring, you are guessing. With measuring, you are managing.

A max-min thermometer tells you whether the growing space cools too much overnight. You might assume the room stays warm enough, but during early morning hours or in winter, temperatures can drop several degrees from what you expect. That slows growth substantially.

A digital hygrometer gives you real-time humidity data. The optimal range for Psilocybe cubensis is 85 to 95 percent relative humidity. Below 80 percent, the substrate surface dries too quickly and pins stall. Above 95 percent without adequate air exchange, bacterial contamination risk rises.

Responsible Use of Psilocybin Mushrooms

Mushrooms from an XL grow kit are for personal use. The quantities a well-managed XL kit produces are substantial. That warrants conscious handling of what you grow.

Psilocybin mushrooms are not a casual product. Experiences can be intense even at modest doses. Set (mindset) and setting (environment) influence the experience at least as much as dose does. Users consistently report the best outcomes in a familiar environment, with people they trust nearby, and without other substances in their system.

Dosing: a widely used reference point for dried cubensis is 1 to 2 grams for a mild experience, 2 to 3.5 grams for a moderate one. Higher doses are not for inexperienced users. Start low, build knowledge and never escalate too fast.

This product is not appropriate for people under 18, pregnant women, or anyone with a personal or family history of psychosis or serious psychiatric conditions. Do not combine psilocybin with lithium or MAO inhibitors; these combinations carry genuine risks.

FAQ About XL Grow Kits

How much do XL grow kits yield?

Yields vary by strain, conditions and number of flushes. A well-maintained XL kit typically produces 200 to 400 grams of fresh mushrooms per flush, and three or four flushes are achievable with good care. Fresh mushrooms are approximately 90% water, so 300 grams fresh is roughly 30 grams dried.

Are XL kits suitable for beginners?

We recommend beginners start with a small or medium kit. Not because XL is impossible for first-timers, but because a first grow always involves learning. The cost of a failed XL kit is higher, and the margin for errors is slightly smaller. One successful medium kit harvest is all the experience you need to handle XL confidently.

How long before the first mushrooms appear?

Typically five to fourteen days after the first soak, depending on strain and temperature. At the ideal 23 to 26 degrees, faster-growing strains like B+ can pin within a week. Slower strains like McKennaii may take closer to two weeks. Lower temperatures push everything toward the longer end of that range.

Can I store an XL kit in the fridge?

Yes. Sealed in its original packaging at 2 to 4 degrees Celsius, an XL kit remains viable for several months. Once you open it and begin the first soak, there is no putting it back. Commit to the process from that point on.

What should I do if I see green patches on my kit?

Green patches are Trichoderma, an aggressive mould that colonises substrate quickly and cannot be reversed. Bag the kit in a sealed bin liner and dispose of it. Clean and ventilate the growing area thoroughly. Before starting a new kit, review where hygiene may have been compromised.

How many flushes does an XL kit produce?

Typically two to four, with the first flush being the largest. Yields decrease gradually with each subsequent flush as the mycelium depletes its nutrients. Third and fourth flushes are still productive enough to be worth pursuing, particularly with high-yielding strains.

Is it legal to own a grow kit in the Netherlands?

Yes. Psilocybin mushroom grow kits are legal to buy and possess in the Netherlands. Dutch law prohibits dried mushrooms, not grow kits or the cultivation of mushrooms for personal use. Check the law in your own country if you are ordering from outside the Netherlands.

Which XL grow kit gives the highest yield?

B+, Golden Teacher and Colombian are consistently among the highest-yielding strains. They colonise robustly, flush heavily and tolerate minor fluctuations in temperature and humidity. McKennaii and Thai produce excellent results too, but reward more precise conditions. If maximising quantity per cycle is the goal, B+ or Golden Teacher are the most reliable choices.

Looking for more detailed grow guides, strain comparisons or dosing information? Our blog covers all of these topics with practical, experience-based content. If you have a specific question about a strain or an issue with your grow kit, our customer support team gives real answers based on fifteen years of working with growers at every level. We stock the full range of grow kit sizes, from small to medium to XL, along with spore materials, liquid cultures and all the accessories needed for a complete grow setup. Everything in one place, selected on quality, shipped with care.

We also carry the full range of complementary grow kit types: 100% Mycelium Kits for the fastest possible colonisation start, Copelandia Hawaiian Grow Kits for a completely different species profile, and Royale Flush Grow Kits for growers who want exceptional flush weights as their primary goal. The full picture of what we offer is on the main mushroom grow kits page.