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Black Pearl King Oyster Mushroom Grain Spawn Bag

Black Pearl King Oyster Mushroom Grain Spawn Bag

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Our Black Pearl King Oyster (Pleurotus ostreatus x eryngii) Mushroom Spawn Bag is made from a high-yielding G1 master culture strain, specially designed to yield thick, dense, and delicious mushrooms with ease. The spawn comes ready to mix with substrate, meaning there’s no need to faff around inoculating and colonising your own grain; you can get straight to the fun part! The ease of use makes it perfect for both hobbyists and small-scale commercial growers.

With our specifically selected high-yielding genetics, you can expect large harvests of up to 350g of mushrooms per kg of substrate.

🍄 Lab tested, high-quality living grain spawn, perfect for inoculating substrates

🌱 Compatible with a range of substrates and growing methods

🧬 Specially selected strains optimised for high yield, nutrient density, and flavour

🗓️ Harvest mushrooms typically within 3 to 4 weeks

🛡️ Guaranteed to produce mushrooms or we’ll replace your spawn free of charge

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Description

THE HASSLE FREE, READY TO SPAWN SOLUTION TO GROWING BLACK PEARL KING OYSTER MUSHROOMS AT HOME

Black Pearl King Oyster mushrooms has roots in East Asian cultivation, where Oyster and King Oyster varieties have been grown and cooked for generations. It is a relatively modern cross, but it carries the same practical appeal that made its parent varieties staples in home kitchens. 

Nutritionally, it offers the same general profile associated with Oyster and King Oyster mushrooms. It provides fibre and beta glucans (1), which some research suggests may support normal immune function as part of a balanced diet. It also contains B vitamins and minerals that contribute to everyday nutritional needs (2)

Unlike thinner oyster types, Black Pearl King Oyster mushrooms develop a dense stem and broad cap with a firm bite. When you slice it thick and cook it slowly, the texture becomes layered and almost scallop like. If you score the stem and sear it in a hot pan with a little oil, it browns deeply and keeps its structure. It does not collapse into softness unless you overcook it.

Growing your own Black Pearl King Oyster mushroom at home has never been easier with our Black Pearl King Oyster Grain Spawn. Whether you’re a seasoned grower or a complete beginner, our spawn takes the guesswork out of mushroom cultivation and turns it into a fun, straightforward process. Say goodbye to complex setups and hello to thick, dense, and luscious clusters of mushrooms, ready to be cooked, extracted or made into a tea.  

Our grain spawn comes with everything you need in one convenient package: a pre-colonised bag of Black Pearl King Oyster Grain Spawn that is ready to go right out of the box - no need for messy inoculations or waiting periods.  

Simply follow our easy step-by-step guide, and watch your mushrooms grow! With minimal effort and space required, you’ll be harvesting beautiful, delicious Black Pearl King Oyster mushrooms in as little as three weeks. 

THE BENEFITS

  • Lab-tested, high-quality living grain spawn, perfect for inoculating substrates
  • Compatible with a range of substrates and growing methods
  • Specially selected strains optimised for high yield, nutrient density, and flavour
  • Harvest mushrooms quickly within 3 weeks
  • Guaranteed to produce mushrooms or we’ll replace your spawn free of charge
  • Save money by growing your own mushrooms at home
  • Little space required to grow & is discreet with no smells
  • Black Pearl King Oyster is packed with bioactive compounds like beta-glucans

HOW TO USE 

The process is simple:

Inoculation: Mix the grain spawn with the substrate at a roughly 6:1 ratio, depending on the specific substrate you’re using. We recommend hardwood sawdust or Masters Mix (50/50 hardwood and soy hulls) for Black Pearl King Oysters.

Top or Side Fruiting: You can cut a small “X” in the side or cut the top of the bag. Unlike regular oysters, these can fruit beautifully from the top to develop their signature thick, meaty stems. Make sure to spray at least twice a day to keep the cut area moist.

Humidity-Controlled Chamber: Finally, you can place the fruiting block in a chamber such as a MonoTub or Martha tent for optimal growth, as this will help maintain the consistent humidity levels these mushrooms prefer.

Gone are the days of having to trawl through decade-old forum posts to figure out the fascinating but often confusing science that is growing mushrooms. Our step-by-step, easy-to-follow guide ensures a successful harvest, eliminating guesswork and making the whole process a breeze.

GROWING CONDITIONS

Substrate: Hardwood or 50/50 blend of hardwood and soy hulls (Masters Mix) hydrated to around 60%.  

Temperature:

  • Colonisation: Around 25°C (77°F) for optimal mycelium growth.     
  • Fruiting: 13–17°C to encourage primordia formation.  

Humidity: High humidity (over 80%) is essential for healthy, large fruits. Use misting, humidifiers, or a fruiting chamber to maintain humidity.  

Light:

  • Colonisation: Complete darkness is preferred for rapid colonisation.    
  • Fruiting: Indirect sunlight or ambient light is sufficient.  

Fresh Air Exchange (FAE): Proper ventilation is necessary to provide the growing mushrooms with fresh air and prevent the buildup of carbon dioxide, which can inhibit growth.    

Sterility: Maintaining a clean and sterile environment is paramount to prevent contamination from other fungi or bacteria, which can compete with the mycelium and hinder its growth. 

INGREDIENTS  

Great mushrooms begin with great spawn. That is why we only use our 100% natural and organic grain in our spawn. We only use high-quality, natural ingredients for our products, specifically selected to support the optimal growth of Black Pearl King Oyster mushrooms. 

Our optimally hydrated millet and milo blend is ideal for spawn production because it colonises quickly and resists contamination better than many other grains, including Rye. We first soak and then cook our grain, carefully hydrating it to around 50% water content before sterilising the bags in a computer-controlled steam autoclave for 2 hours at 121°C. 

This is then inoculated with our own Black Pearl King Oyster liquid culture, the substrate providing the perfect nutrient rich environment for mycelium, promoting rapid colonisation, large yields and minimal risk of contamination.  

WHAT’S INCLUDED 

  • 1.5kg Black Pearl King Oyster Mushroom Grain Spawn Bag

WE DO NOT INCLUDE  

Physical copy of the growing guide: You can find our online step-by-step mushroom growing guide here, as well as some of our own tips and tricks for optimising your grow. We highly recommend reading it before purchasing! 

STORAGE 

Please aim to use your Black Pearl King Oyster Mushroom Grain Spawn Bag soon after receiving it. If you are not using right away, store the bag in the fridge. Stored this way, your spawn should last at least 3 months. 

  • EASY TO USE

  • MASSIVE YIELDS

  • SET & FORGET

  • SAVE MONEY

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What people are saying

  • INJECT BAG

  • WAIT 4-6 WEEKS

  • HARVEST MUSHROOMS

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MARTIAN MUSHROOMS

  • Can grow multiple mushrooms
  • QC lab tested for contaminants
  • Easy to use with help from our mycologists
  • Lifetime guarantee protected
  • High yielding millet and milo substrate blend
  • Rapid colonisation times
  • Simple set & forget growing
  • Fun step by step guided process

GENERIC GROW KITS

  • Only grows a few species
  • Untested for contamination
  • Difficult to use without any on hand help
  • Not protected if something goes wrong
  • Lower yielding substrate
  • Slow colonising weak genetics
  • Lots of steps to get mushrooms
  • Frustrating to use with long process

FAQ

DOES THIS COME WITH SPORES OR CULTURE SYRINGE?

There is NO spore or culture syringe included with the Blank Grain Spawn Bag. It is non-inoculated to allow you to inject the species of your choice. Liquid cultures for gourmet varieties are available here.

HOW MANY SYRINGES DO I NEED?

You only need 5ml of spore or liquid culture solution per bag, so one syringe can inoculate 2 bags. We don’t recommend using more than 5ml per bag, because too much liquid can throw off the moisture content within the bag. 

You can store any unused solution in the fridge for future use. Stored that way, they’ll keep for many months. 

HOW IS THIS GRAIN BAG USED?

Fortunately, it’s really easy to use, you just need to follow our guides by clicking here.

HOW DO I STORE THIS GROW KIT?

Ideally do not store your grow kit and inoculate right away, if you are not using right away keep your kit in the fridge.

WHAT MUSHROOMS CAN BE GROWN WITH THIS KIT?

Our Martian Mushrooms kits are designed with versatility in mind and can support the growth of various edible and ornamental mushroom species. Some popular types of mushrooms that can be grown with our kits include Oyster mushrooms, Shiitake mushrooms, Lion’s Mane, Reishi, Chaga, Turkey Tail and many others that are legal and safe for cultivation at home.

It’s important to note that while our kits can technically support the growth of various types of mushrooms, we strongly advise against and do not condone the use of our kits for the cultivation of mushrooms that are illegal to grow in your country. This is due to the legal restrictions in many regions, including the UK where we are based, it is illegal to cultivate certain species of mushrooms.

At Martian Mushrooms, we are committed to promoting responsible and legal use of our products. We reserve the right to refuse service to anyone suspected of intending to use our products for illegal purposes. Always check and comply with your local laws and regulations regarding the cultivation and possession of mushrooms. Any customer service requests regarding the cultivation of illegal species will be ignored. 

CAN I GROW MULTIPLE TYPES OF MUSHROOMS WITH THE SAME KIT?

We dont recommend growing more than one type of mushroom per kit. Growing multiple types of mushrooms may result in poor flushes.

WHERE DOES THIS PRODUCT SHIP TO?

Please refer to our delivery details 

HOW LONG DOES IT TAKE TO GROW?

It will depend on a few different factors, mainly temperature. But it will range from about 4-8 weeks. 

FAQ

Our pre-colonised Black Pearl King Oyster Mushroom Grain Spawn Bag doesn't include spores or liquid culture, as it is already pre-colonised with Black Pearl Oyster King mycelium and ready to spawn with substrate. 

Fortunately, it’s really easy to use; you just need to follow our guides by clicking here.

WE DO NOT INCLUDE  

Physical copy of the growing guide: You can find our online step-by-step mushroom growing guide here, as well as some of our own tips and tricks for optimising your grow. We highly recommend reading it before purchasing!

Please aim to use your Black Pearl King Oyster Mushroom Grain Spawn Bag soon after receiving it. If you are not using right away, store the bag in the fridge. Stored this way, your spawn should last at least 3 months.

Please refer to delivery details.

Black Pearl King Oyster mushrooms typically take about 2 to 3 weeks to start fruiting from a fully colonised block, provided the conditions are optimal. This timeframe depends on maintaining the right environment, including high humidity (85-95%), temperatures around 13-17°C, and a careful balance of air exchange. Once pins appear, they usually take7 to 10 days to develop into full-sized fruiting bodies, with their signature marbled dark caps expanding and their thick, meaty stems thickening as they reach maturity.

Biological products, by their very nature, can be unpredictable and sometimes things don’t go as planned. Growing mushrooms is always a battle against contamination, and sometimes it wins.

When things go wrong, don’t worry. We offer replacements for contaminated kits or substrates as our guarantee

Ensure the humidity is high by misting once or twice daily or using a humidity chamber. Make sure there's enough airflow by providing proper ventilation. Keep the temperature between 13-17°C (55-63°F), and place the kit in indirect light. If the substrate looks dry, mist more often or soak it briefly and let it drain. Sometimes, it just takes more time, so be patient. You can also try cutting a small “X” in the side of the bag for side fruiting. Check for any contamination, like mold. If you still need help, contact our support team!

Black Pearl King Oyster mushrooms are very sensitive to high CO2 levels. If there isn’t enough FAE, they may not fruit at all or produce long, thin stems with small caps. 

Ensure your setup has proper humidity, regular misting, and enough airflow to reduce CO2 buildup. Adjusting these factors should encourage fruiting.

Yields can vary substantially based on the genetics of the mushrooms you’re growing, environmental conditions and amount of substrate you are using. Typically, you can expect to grow 750g+ fresh mushrooms over several flushes from a 1.5kg spawn bag.

If we did not answer any of your questions above, then contact us here. We are always happy to help and look forward to hearing from you.