May 21, 2016

HIGH MOUNTAIN COMPOST                           

How to Use our Mushroom Growing Compost and KITS

Basically these kit instructions detail each step towards successful mushroom growing. Most of it’s just common sense, like sterilizing your hands before handling the compost, to prevent contamination.  The kit includes everything you need except spore solution. No casing is required.



When your kit arrives, the box will include the growing chamber (plastic tub), two bags of rye berry grain substrate, and a 10-lb bag of compost. Because each kit is used with only one bag of rye grain substrate at a time, you’ll want to store the second bag of rye berries and the 10-lb bag of compost in a refrigerator or other cool dark place for later use.

PREPARE Cleanliness is the key to success. Sterilize your hands/arms with 70% alcohol before touching anything. Prepare a work area off the floor by spraying with 70% alcohol solution, wiping and letting it dry. (If you want to use the empty growing chamber to hold the rye berry substrate bag while it colonizes, you must also clean the chamber with a 70% alcohol solution and let it dry.)

DO NOT use any bags of grain that appear unhealthy or that you think might be contaminated. Smell through the patch; if the grain smells slightly sweet and has a malt aroma, it should be good to use.  A contaminated bag will ruin the compost – and it’s the compost that produces the mass mushrooms, not the grain. So if a bag of grain is questionable, don’t risk using it!

(Note: Occasionally, but rarely, a rye grain bag will not work. Please do not ask us for replacement bags; there are no replacements on these kits, so be cautious of bags of grain that may be unhealthy.)

INJECT & COLONIZE – We assume you already have spore solution on hand when your kit arrives. Begin by wiping off a small area of the pre-sterilized rye grain bag with alcohol. Select a spot below the filter patch, but NOT ON the filter patch.

Poke the needle through the bag of rye berries, and inject 3 to 5 cc’s of spore solution into the bag of grain. Don’t inject more than 5 cc’s per bag or it may be too wet and could develop wet spot bacteria or other unwanted nasties.

After you squirt the spore solution into the bag, tape over the hole.  Give the bag a good shake to distribute the spore solution throughout the grain.

Lay the bag flat, with the grain evenly distributed, and incubate in a dark place at a temperature from 70°F to 80°F.   75 degrees is ideal, while lower temperatures around 70 degrees or below, will drastically slow down colonization, and sometimes prevent germination.

In about 4 to 7 days, you will see healthy white mushroom mycelia growing on the grain.

When the bag of grain is about 40% – 50% colonized, gently shake it to break up the colonizing grain a little to help speed colonization.  Do not squish the rye berries; just gently break them up and distribute them around the bag.  (This step is not strictly necessary, but it can help distribute the mycelia more evenly.)  Give it a few more days and the bag should be 100% colonized.

From the start of incubation to full colonization usually takes an average of 10 – 16 days.


MIX WITH COMPOST – With the bag of rye berries fully colonized, prepare to mix the colonized grain with the HMC compost, using good clean sterile procedures such as described.  This is very important! It’s we humans that usually introduce contamination.

Be sure your hands and arms are cleaned really well with 70% alcohol.  Wear a facemask and don’t breathe on the compost — lots of germs come from our breath.  Wear freshly laundered clothes, and avoid any contact with animals (i.e., pets) or furniture used by pets, before and during the process.

Be sure to wipe down the growing chamber inside and outside, and all surfaces including the grain bag, with 70% alcohol so it’s sterile from germs, dirt, contaminants, etc., that may have been picked up in transit. Remember to let the chamber dry completely before adding compost. Even if you’ve used the empty chamber to hold the rye berries during colonization, clean it again for this step.

Next, you’ll mix the healthy bag of colonized grain with 10 lbs. of compost:

When you’re ready to put all your compost in the chamber box, be sure to clean your hands before handling any of the bags. Put on hospital-type rubber/latex gloves and mist with alcohol, allow to dry.

Remember, you never know what germs are on the outside of these bags before the actual day of use, so try not to touch the outside of the compost bag to the inside of your now-sterile growing chamber.

After dumping the bag of compost into the chamber, clean your hands again with alcohol.  Then open your bag of colonized grain and add it to the compost.  Clean your hands again with alcohol 70%.

Thoroughly mix the colonized grain and compost together.  It is best to break up the grain into BB-size pieces.  More small pieces of colonized grain mean more inoculation sites on the compost, which in turn will help the compost colonize faster and more thoroughly.

Try to level out the surface of the compost so it’s rather even.  Small valleys in the top layer may cause some areas of the surface to fruit faster than others.  Most mushroom mycelia colonize this compost very quickly.

Within 4 to 5 days, your compost should be looking whitish with mycelia. Over the next few days the compost in the chamber will turn into one big, solid, caked mass of mycelium.


PIN & FRUIT — When the compost is fully colonized, you can initiate pinning and fruiting. This is the actual mushroom growth stage. Simply provide a light cycle of 12 hours on/12 hours off, and the mycelia will start pinning and fruiting within 5 – 12 days.  You will soon be harvesting mushrooms (almost there!)  Pick the mushrooms as they fully mature and spores begin to drop. Maintain the 12 on/12 off light cycle, and you should typically see three or more good flushes before the compost is spent. Flushes are usually about 7 – 10 days apart.


Temperature — It is recommended that you keep temperatures between 70° F – 80° F for best results. Lower temps will slow down the colonization process, but will also reduce chances of contamination.

Some strains have fruited on this compost in temperatures as low as 45° F, so these are only guidelines, based on best practices.  Temperature drops of about 10 degrees are not necessary, but they do improve pinning.

Also, we DO NOT recommend using heating pads under these kits.  Even on low setting, they generate too much heat to the bottom.  When colonizing spores in the rye berry bags, try to maintain them at a constant 75°F to 80°F.  At lower temperatures, the spore solution may take longer to colonize.

Light — It is recommended to keep everything in the dark until the compost is fully colonized. While recent scientific reports say that dung-loving mushrooms will tend to give healthier flushes throughout the life cycle if kept in the dark, the downside to this is they may start fruiting too early, thus giving uneven flushes of mushrooms.

For optimal results, we recommend keeping the compost stored in the dark until it is at least 80-70% colonized, or approximately 2 – 3 weeks from when you mixed the grain into the compost. Then give it a 12 on/12 off light cycle.  Normal light from a window across the room is good enough.

Note: If you see your compost colonizing along rapidly and you see a few spots here and there that are not fully colonized, even though it’s been 3 weeks, that’s okay; go ahead and initiate the light cycle.


Humidity — Humidifiers are not needed if using the High Mountain compost inside the supplied chamber.  This compost generates enough humidity that it creates a mini rain forest inside the chamber.  If you see that more than an inch of water has collected in the bottom, remove the tape over the drilled hole that is at the bottom, on the end, to drain the excess liquid off. Replace the tape afterwards.  You may see a lot of condensation and sometimes even small puddles of water on the surface.  This is normal, and the mushrooms will absorb this on the first flush. Sometimes you will also see a yellowing color of the water.  That is a normal indication of the compost metabolizing, basically giving off a waste product from the mycelia.

Air Exchange — Do Not Fan.  These kits come with pre-drilled holes for air exchange.  We have experimented extensively, and these holes work fine for proper air exchange throughout the process.

Colonization — Your kit includes two bags of rye berry grain. Only one bag of healthy colonized grain is needed, but more can be used. Using one bag of grain, the 10 lbs. of compost takes about 10-15 days to become fully colonized, with times varying according to the speed of the strain, temperature, etc.   We’ve even seen these kits flush 3 to 5 times before – although that is exceptional.  Other colonized grain substrates such as brown rice/vermiculite, birdseed, wheat grain etc., also may be used with these kits; you don’t have to use the rye berries we include. Any good healthy colonized spawn will work, so long as it is uncontaminated. Simply verify that the odor is sweet and slightly malt (like old beer).

Contamination — As with ANY substrate involved with mushroom growing, rye berry grain can contaminate this compost with green mold (Trichoderma) or other form of bacteria.  No mushroom substrate is perfect.  All are susceptible to contamination. We have found rye berries are more resistant to contamination than all other grain substrates we have tried.

The strain of mushroom being grown is also a factor in contamination since some strains are more resistant to contamination than others. For example, some strains will grow around green mold just fine, and continue to fruit for short periods of time; others will not.  Most of the time it’s we humans that contaminate our own growing project.

Again, when your kit arrives you should take note that the compost is not green or contaminated.  If it turns green later on, after you started working with it, it is because you or something in your house has caused contamination.  Therefore, keep everything away from pets, and elevate your kit off the floor because this is where most contaminates are.  Always, always, wipe your hands/arms down with 70% alcohol before each step.

Using these directions, you should soon see successful results from your efforts. Enjoy the fruits of your labors, and thank you for using High Mountain Compost Kits!



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