How to Grow Morel Mushrooms Outdoors

I describe here how I prepared beds that were 16 square feet total to grow morel mushrooms outdoors using morel sawdust spawn from North Spore. OK, let’s be real, I didn’t really make them that large, but this was the basic recipe I followed. This protocol was based on the methods described in Organic Mushroom Farming and Mycoremediation by Tradd Cotter (2014)*. Even though this article doesn’t include a morel mushroom slurry recipe, you can absolutely combine the methods described for preparing the beds with making a morel slurry. Also know that I have prepared the morel mushroom beds this year (2022), but only time will tell if they will fruit. Make adjustments as needed. Nothing ever goes completely as planned. Just do the best you can!

Time of Year To Grow Morel Mushrooms Outdoors

In Organic Mushroom Farming and Mycoremediation, Cotter (2014) recommends preparing your morel beds in the spring at the time that morels fruit and thus sporulate. I constructed my morel beds in late spring June 8-9, well past the time of most morels fruiting. I am uncertain if this will affect my results, but that was when I was ready and did not want to miss out on giving it a try this year!

The Basic Anatomy of a Morel Mushroom Bed

According to Cotter (2014), morel beds have three layers and can have two different configurations. The first option is, one being the most shallow layer and three being the deepest layer:

1. Spawned Layer
2. Nonnutritive Layer
3. Nutritive Layer

OR

1. Nonnutritive Layer
2. Spawned Layer
3. Nutritive Layer

The reason for this layout is that morels produce survival structures called sclerotia in the nonnutritive soil (Cotter 2014). They then send out filaments called hyphae to locate and send nutrients back to the nonnutritive layer. The nutrients are then stored in the sclerotia, which will generate fruiting bodies with the right time and conditions. If you just put morel spawn on top of a nutritive layer, without an adjacent nonnutritive layer present, it will likely feel too safe and comfy to produce sclerotia. Now the odds of the morel ever producing fruiting bodies in that location greatly decreases. I chose the first configuration, knowing the morel spawn would have to work harder to reach the nutrients. Whichever order of layers you choose, make sure you do Not mix the nutritive and nonnutritive layers!

Materials You Will Need to Grow Morel Mushrooms Outdoors

(Based on Cotter’s [2014] recommendations):

• Newspaper or Packing Paper. Ideally for two 2-foot by 8-foot layers (one at the base of and one on top of the nutritive layer).
• Fresh or dried sawdust. Soak your sawdust overnight and drain it. Try to obtain sawdust that is from the host species for your morel strain. Obtain roughly 8 cubic feet for the 2-foot by 8-foot bed you will prepare.
• pH testing tool, either testing strips or pH meter. You can try either, though a pH meter is generally more accurate.
• Garden lime to raise pH and aluminum sulfate to lower pH. If you know the baseline pH of your soil to be more acidic, you can omit the aluminum sulfate.
• Wheat bran or soy meal (5 pounds total). You can obtain these from a farm supply store. I bought wheat bran at my local grocery store. Ideally I’d go organic, because it is part of the substrate that will feed and become the morels.
• Hydrated limestone, 1 pound.
• Dried coconut coir, 3.8 cubic feet.
• Sand. You’ll want it to be extra fine sand, 50 pounds.
• Spawn. Home-grown morel spore slurry or purchased sawdust morel spawn (know a 5-lb. package can be spread up to 200 square feet). I did plots with both, just preparing a slurry from a portion of my purchased sawdust spawn (more on this in a future blog post). Usually you would prepare a slurry from a morel specimen you collected in the field. I couldn’t find a wild morel, so here we are!
• Optional but useful materials:
  • Chicken or poultry wire. For –you guessed it, keeping out them critters. ‘Cause who needs them mucking up your hard work!
  • Logs or untreated lumber to make a frame around your bed. Some people like to frame their work.

Constructing Your Beds to Grow Morel Mushrooms Outdoors

First, Cotter (2014) says to pick a shaded area to make your bed(s). Think of areas that morels would like, like next to a stream, a place with ideally sandy, loamy, and well-drained soil. Also consider habitats that have the host trees morels tend to associate with, like tulip poplar, ash, cottonwood, or spruce. Certainly consider if there are any particular hosts associated with your morel species.

As mentioned, this tutorial is for 16 square footage of bed. So you can go as simple as 2 feet wide and 8 feet long, and 8 to 10 inches deep. I would split that square footage into multiple beds, and space them out a few to several feet. This will diversify the microenvironments of the soil and surrounding trees, increasing your chances for success. I dug my beds in the woods, without considering how dense the forest soil would be with tree roots. Needless to say, my beds were definitely not 16 square feet in total, but I tried my best!

Remember how I said you want newspaper/packing paper for two layers worth of 16 square feet? The first layer goes on the base of your bed, and make sure it is wet. Honestly, I skipped this step as my beds were so dense with roots poking through. If you have a tool to trim the roots, it would be easier to line the bottom of your bed!

Fill Your Morel Bed with Nutritive Medium (i.e., food for morels!)

Now we’re starting to get to the more fun stuff, our fungal food for our morel spawn. We want to try to use sawdust (or wood chips) that matches the host species of the morel we are cultivating. The spawn I used to grow morel mushrooms outdoors is a burn morel species from New England (a rare find in New England). North Spore says it was harvested from a burnt pitch pine forest. I figured it would be interesting to try various sawdust substrates since I wasn’t 100% clear on the original host. First I decided to get some apple wood substrate for growing morel mushrooms. I got a bundle of Gravenstein apple tree cuttings off the Internet for $5.00.

Mulching My Own Substrate and Purchasing The Rest

After hauling home the apple wood, I let the apple tree cuttings dry out in the sun for about four to six weeks. I decided to buy a small electric Wen wood chipper (not sponsored). Most of the cuttings would fit as long as they were 1.5 inches in diameter or less. It took me several hours to do this but was far easier than manually chopping them into bits. I’m not a lumberjack, after all. Starting off, this bundle of cuttings was four feet long and a couple feet thick. After mulching, it filled a 13 gallon trash bag plus one cubic square foot in my mulching bag. So I got roughly 2-2.5 cubic feet of apple mulch from my efforts.

Then I went a less effortful route. I bought one bag of hemlock mulch (2 cu. ft) and two bags of pine mulch (2 cu. ft each). Honestly, I don’t know how organically sourced the store-bought mulches were (I don’t recommend buying mulch that might have dyes in it). However, I figured they were relatively non-toxically sourced (let’s hope?). Safer sources of sawdust to grow morel mushrooms outdoors may be your local sawmill. You may also obtain chip mixes from roadside crews pruning under power lines (keeping tree host species in mind). Anyhow, onto the completion of this nutritive medium business!

(**Note: I only had about 8 cu. ft of sawdust/mulch, so I was probably short a few cu. ft for the ideal 16 cu. ft.)

Preparing the Sawdust for Your Morel Beds

Soaking Your Sawdust and Adjusting the pH

In preparation of the nutritive medium to grow morel mushrooms outdoors, Cotter (2014) recommends soaking the sawdust overnight to hydrate it. You can then squeeze out a small bit of water to test the pH, with a target pH of 7 and 8. Then you can add garden lime to alkalize or aluminum sulfate to acidify your sawdust. However, I did not do the overnight soak, and just soaked my sawdust the day of. You see, I knew I was going to haul all of this heavy material deep into the woods by myself. But hey, you do you!

When soaking your sawdust, use the cleanest accessible water to you. Avoid using chlorinated water. If using a garden hose, run the water for 5-10 seconds to let any leached chemicals from the hose to clear out first. Be sure to soak your sawdust but don’t waterlog it. Then I drained any excess water that pooled at the bottom of my mixing tub.

Adding Your Morel Mushroom Nutritive Substrate

Once your sawdust is nice and soaked and is in the proper pH range (7-8), mix about 10 percent wheat bran or soy meal by volume into your sawdust (Cotter 2014). Next, fill your morel bed six to eight inches deep with nutritive medium. Leave one to two inches of space for the nonnutritive layer. Then level your sawdust mixture with a rake and tamp (or stomp on) this layer. This is an important step because morels need a tightly packed growing medium. These morels are all business, no fluff!

Adding Lime onto the Nutritive Layer to Serve as a pH Buffer

Now that you’ve tamped out your beds, Cotter (2014) says to evenly sprinkle pelletized lime 1 cup per 16 square feet on top of your nutritive layer. This will serve as a slow-release pH buffer; the bed will acidify some as the growing morel mycelia (or fungal tissue) feed on the nutritive layer. Additionally, the morels will appreciate the extra calcium to make sclerotia. Then water the bed well to wet the nutritive medium. Once again, level and tamp. Place one layer of wet newspaper to provide a barrier from the nonnutritive layer that we add next.

Prepare the Nonnutritive Layer

Here we mix the sand and coconut coir in a 1:1 ratio in a tub (Cotter 2014). Make enough to cover the nutritive layer 1 to 2 inches deep. Water the soil so it drips a few drops of water when squeezing a fistful of the mixture. Then adjust by adding more sand and coco if too wet or add more water. Test the moisture by squeezing the soil with your fists. Next, test the pH of the soil, getting it between 7 and 8. If the soil is acidic, mix lime (1 cup) into the mixture. Cotter (2014) says to squeeze the sand mixture until the pH remains stable at 7-8 for at least an hour. However, I didn’t wait an hour, as time didn’t allow for that. After adjusting the pH, empty the excess water. Now it is ready to go on top of the nutritive layer.

When adding the nonnutritive soil, use a ruler to check that the soil is 1 to 2 inches deep (Cotter 2014). Flatten this soil over the newspaper barrier. Add as much as necessary to create a layer 1-2 inches deep. You can use a broom or rake handle to press small indentations into the soil. The bumpy surface will support your morel spawn. I didn’t do much of this myself as the nonnutritive layer already packed out somewhat bumpy. The morel mycelia are less likely to dry out with all the comfy little soil pockets. Since this is a burn morel spawn that I used (which fruits after forest fires), I coated this layer with hardwood ashes. I just took whatever ashes I could get from my parents’ fireplace. I consider the ashes optional and experimental.

Inoculate Your Morel Beds

Now it’s time to inoculate! To grow morel mushrooms outdoors, distribute 1/4 cup of your spawn per square foot of bed over the nonnutritive layer (Cotter 2014). Then cover the bed with leaves or straw (ideally pesticide-free) 1 to 2 inches deep. This provides shade and moisture protection in its early stages of growth. This is the part where you can protect your beds from critters with chicken wire, etc.

Here is a hunk of morel spawn! Definitely break this hunk into smaller bits. A little goes a long way here:

The source of my spawn to grow morel mushrooms outdoors –North Spore! This is spawn for a black morel species.:

Water Your Growing Morels

Next, make sure to water your beds well immediately after inoculating them. For the next two months, water your morel beds to keep them moist but not soggy (Cotter 2014). I have watered my beds once a week, especially if it didn’t rain that week. Decrease watering to once a month from late summer through mid-autumn (August through October in the Northern Hemisphere; December through February in the Southern Hemisphere). According to Cotter (2014), during this period, morel mycelium can grow one inch/day. That’s kind of intense, huh?

Here are two of my morel beds, covered with leaves and watered.:

Flood and Freeze Your Morels

In autumn, when a winter freeze is supposed to hit your area, slowly flood (saturate) the bed the night before the freeze (Cotter 2014). This means the temperature is dropping to 32°F (0°C) or below. This flooding triggers the morels to feed on beneficial bacteria important for fruiting.

Spring Thaw and Fruiting Stage

During the spring thaw, sclerotia that grew in the nonnutritive layer swell with water and start to develop young morel tissues (Cotter 2014). Now is the time to watch your bed and local soil temperatures. Morels usually fruit when soil temperatures are 48 to 56°F (9-13°C).

*Mid-August 2022 Update:

In Cotter’s (2014) chapter Morel Cultivation: Research Update in Organic Mushroom Farming and Mycoremediation, a man who shared his secrets with him would see sclerotia appear in midwinter. He would check for them under the leaf litter and see numerous, small, cinnamon-colored, stone-like bumps in his morel beds. He does not mention how big these clusters of sclerotia became, or how small they were at first. About nine weeks after I inoculated my beds with morel spawn, I have started to see cinnamon-colored little bumps. They varied in color from yellowish-brown, to reddish-brown to dark brown (see photo below). The bumps were extremely small, no larger than one or two millimeters in diameter. I did not expect to see anything noteworthy this early. These were in areas where the leaves didn’t thoroughly cover the beds. Here is a visual of what I saw:

Stay tuned for more updates!

If you’ve read this far, you deserve a June 2023 update, right? This year, I did not appear to get any fruiting in my morel beds. Womp, womp. Does this mean it was a fail? Not necessarily, because I’ve read that it can take two years for morel beds to fruit.

**SAFETY DISCLAIMER: Do not ever eat morels raw. Eat a small amount of cooked morels and see how your body responds to them before eating larger quantities. Some people have a dietary sensitivity to mushrooms they don’t generally eat. If foraging for wild morels, be sure to discern them from false morels, which are toxic. Do your research and be safe!

*Full Reference: Cotter, T. (2014). Organic Mushroom Farming and Mycoremediation: Simple to Advanced and Experimental Techniques for Indoor and Outdoor Cultivation. (1st ed.). Chelsea Green Publishing.