How To Grow Oyster Mushrooms in Buckets

How To Grow Oyster Mushrooms in Buckets

A quick Google search will show you there is a great deal more to mushroom cultivation than what meets the eye. Amateur growers are bombarded with terms such as “substrate”, “spawn”, and “colonization time.” It is hard to know where to begin your journey. 

What do you need?

A quick Google search will show you there is a great deal more to mushroom cultivation than what meets the eye. Amateur growers are bombarded with terms such as “substrate”, “spawn”, and “colonization time.” It is hard to know where to begin your journey. 

This blog will outline the bucket method of growing mushrooms. This method is fantastic for beginners who have already tried Forij Indoor Grow Kits and would like to take their mushroom cultivation journey to the next level. The Bucket Tek is straightforward and does not require any fancy equipment. To grow several harvests (“flushes”) of the Oyster mushrooms of your choice all you need is:

*You can opt to skip the pasteurisation step by purchasing four to five quantities of Forij Woodworks fruiting blocks per 5 gallon bucket in replace of your wood chips or straw. 

What goes into the bucket? - Substrate and Grain Spawn


Like humans, all species of fungi have preferences for how they nourish themselves. In mycology, the nutrient source for a fungus is referred to as a “substrate”. In nature, Saprophytic basidiomycota species such as Pleurotus (oyster mushrooms) are found growing on decaying hardwood logs. However, oysters are able to colonize an array of different substrates, straw included. 

Please note you can skip this substrate preparation step entirely by purchasing a few quantities of Forij Woodworks fruiting blocks (4-5 per 5-gallon bucket), which contain enriched hardwood sawdust that is already pre-hydrated and sterilized with no contaminants and an indefinite shelf life! If you choose the Woodworks route, move onto the Grain Spawn step. However, if you want to go the classic route, read on.

In this Bucket Tek, we will use either Aspen wood chips or straw, depending on what you have handy. Aspen wood chips can be easily found at pet stores as bedding for rabbits or gerbils. Straw can also be found at your local Home Depot or hardware store. Some folks opt to use a pressure cooker to pasteurize their substrate, however because wood chips and straw are two substrates that are not appealing to any other types of fungi or bacteria in the air besides saprophytes, a “simple” pasteurization using a tote and boiling water left overnight will do. 

Start by prepping the straw or wood chips! If you are using straw, chop up the straw in 2-3’’ segments. The chips / straw need to be soaked in hot water. The goal is to get the temperature to about 70oC for wood chips. Most hot water taps run at about 50oC, so we recommend supplementing the tap water with 50% boiling water. However, if you are pasteurizing straw, which often comes with more contaminants than wood chips, make sure you use only boiling water. Mix the wood chips (or straw) in a large plastic tote (over 13L capacity) or whatever you have, so the water is dispersed throughout. They should be fully submerged. Since wood is less dense than water the chips will float. It may be necessary to set the lid, or another heavy object over the tote to stop the chips from spilling.

Leave your substrate to soak until the water has completely cooled down. If you are using straw, wait 30 minutes to 1.5 hours and use immediately—straw is more contamination prone so it is best to use shortly after pasteurisation to minimise growth of mould or bacteria. If you use wood chips, the substrate will take at least 10 hours, so we would recommend letting it sit overnight. If you use the substrate prior to when it has fully cooled off, you run the risk of killing the mycelium in your grain spawn! 

Next, you will need to drain the excess water. This can be achieved in several different ways, you could drain it in a bathtub or in your yard. You can also expel excess water by squeezing your fist as you go. Whatever works for you.  You want the sawdust to be at “field capacity”, meaning when you squeeze it in your fist a very small stream of water, or just a few drops, is expelled. 

Grain spawn

Grain spawn is created when the fungal roots, called mycelium, spread throughout the grain and consume it. Creating grain spawn is a tricky process involving a laminar flow hood and sterile procedure. For beginners, it is easiest to buy premade Forij spawn. The species we recommend growing in the bucket are oyster (Pleurotus) species: blue, white, golden, and pink. Pink and golden will do better in warm weather. Lion’s mane (Hericium erinaceus) can also be grown with this technique, but it’s mycelium is not as robust as that of the oyster species and takes much longer to grow. We recommend oysters for beginners. 

Prepping the Bucket

In addition to the pasteurised substrate, to get started you need a 5-gallon (13L) bucket with a lid. Do not forget the lid! These can be purchased at most hardware stores. If you are planning on using a bucket that has been sitting around your house, make sure to wipe it down thoroughly with isopropyl alcohol to avoid contamination. We recommend a new bucket if you intend on consuming your mushrooms. 

You will also need a power drill with a ¼”  drill bit, larger if you prefer. ¼’’ seems to be an ideal hole length--just large enough to form robust, sturdy stems to fruit large clusters of mushrooms, while small enough to maintain the humidity within the bucket. There is no science to the number of holes--just make sure you drill on the sides of the bucket and the holes are at least 5cm apart. There is no need to drill any holes on the bottom.  

Loading the Bucket

After wiping the bucket down with isopropanol or disinfectant, use clean gloved hands to begin to layer your substrates. Start by making a layer of wood chips / straw or Woodworks about 5cm thick in the bottom of your bucket. Sprinkle the grain spawn over the layer of hardwood or straw and repeat the process in a lasagne-like pattern until the bucket is full, ending with a layer of wood chips or straw so that no bits of grain spawn are left exposed . Per 5-gallon bucket we recommend you use 2-5lbs of spawn, which is about 5-10% of the substrate. This means that for every 5lb bag of Forij grain spawn, you can produce 1-2 buckets worth of mushrooms. Place the lid on the bucket after filling. Do not touch the spawn directly unless wearing disposable gloves, as it is prone to contamination. 

Colonization and Harvesting

Colonization is the act of mycelium spreading throughout the hardwood substrate, just as it did to colonize grain spawn. This process may take 1-3 weeks depending on species, spawn ratio, and environment. During this time your bucket should be kept in a place away from direct sunlight such as a porch (if it’s not too hot out) or a garage. Either ambient light or darkness is fine, at this stage, but exposure to direct sunlight will hinder growth.

Mushrooms require moisture to grow. If you are in a dry environment, we recommend loosely draping a plastic bag over the bucket and occasionally misting it with water. This will create a more humid microclimate and allow the substrate to maintain its moisture.

Once you see baby mushrooms “pins” begin to appear they grow fast so be sure to check in every day. It is a fascinating process that you do not want to miss! Fruiting can be done indoors, or you can move your bucket to a shady spot, away from any strong wind outside. Using a spray bottle, mist your bucket at least twice daily, to keep the mushrooms moist. If conditions are too dry the pins may die. 

Once the caps flatten it is time to harvest! Cut off the entire cluster at once, either with a knife or by twisting and pulling. Continue to mist your bucket after harvesting as the second flush is on the way. You may get up to 4 flushes if you take good care of your fruiting environment .

Keep an eye out for mold growth or foul smells. If there is no growth after 3 weeks and your bucket smells rotten, you have encountered contamination. This can be caused by several environmental factors. Mycology can be tricky, don’t despair. Just throw the bucket out and try again! We promise you it’ll be all worth it when you see beautiful clusters of oysters fruiting out of bucket holes. 

You will be eager to eat your fresh gourmet mushrooms, but do not forget to cook them thoroughly! And if you are a visual learner be sure to check out the video made by our friends at Fresh Cap Mushrooms. 

Get growing what you need minus the bucket here!