Harvesting Mushroom Spores: A Step-By-Step Guide

Mushrooms are a fascinating family of fungi, with some species being edible and flavourful, while others are vibrant and impressive to look at. Growing mushrooms from spores is fairly involved and requires some equipment and knowledge of biology and science. The most common method for harvesting spores from mushrooms is making a spore print. To do this, you'll need a mature mushroom with gills, a piece of paper, and a glass container. After cutting off the stem, place the mushroom gill-side down onto the paper and cover it with the glass container. Leave it overnight, and by the next day, the spores will have dropped from the cap onto the paper. This simple method allows anyone to try growing mushrooms at home, but keep in mind that it requires patience and attention to detail to be successful.

Choosing the right mushroom

Maturity and Readiness to Release Spores

Select a mature mushroom that is ready to release its spores. Look for a mushroom with gills that are moist and apparent. Avoid mushrooms with brown spots, mushy areas, or dry gills, as they may be less likely to produce spores.

Edibility and Safety

If you plan to consume the mushrooms, choose a variety that is known to be safe and edible. It is generally safer to buy mushrooms from a store or grow edible varieties from spores, as consuming wild mushrooms can be dangerous.

Mushroom Variety and Substrate Compatibility

Different mushrooms prefer different growing media or substrates. Common substrates include wood, manure, grain, and straw. For example, oyster mushrooms thrive in straw, while portobellos favour manure. Research the specific requirements of the mushroom variety you choose to determine the appropriate substrate and growing conditions.

Spore Availability and Ease of Collection

Not all mushrooms release spores in a manner that is easy to collect. Gill mushrooms, such as button mushrooms, are the easiest from which to harvest spores due to the ribbed structure beneath their caps, which houses the spores. However, with experimentation, spores from all types of mushrooms can be harvested.

Mycelium Health

A thriving mycelium network is crucial for successful mushroom cultivation. When harvesting mushrooms, inflict as little damage as possible on the mycelium. Gently twist the mushrooms at the base of their stems to detach them.

Remember, choosing the right mushroom variety, understanding its unique requirements, and paying attention to the details of the cultivation process will increase your chances of a fruitful harvest.

Preparing the mushroom

Once you have selected a suitable mushroom, place it gill-side down onto a piece of sterilised wax paper or aluminium foil. If you want to be as sterile as possible, use heat-sterilised tweezers to touch the cap. If you want to keep the stem attached, cut a hole in an index card, place it over a bowl, and insert the stem into the hole so the cap rests on the paper. If you are removing the stem, place the cap spore-side down. Do not press down on the mushroom as you may crush it.

If your mushroom has pores instead of gills, you can still extract the spores following this method. Put the cap pore-side down, as the pores will often face the same direction as the gills. You can add a drop of water to the top of the mushroom to keep it moist and encourage spore release, but be careful not to soak the mushroom or you may ruin the spores.

Preparing the surface

To prepare the surface for spore printing, you will need a few simple materials:

• Paper: Choose a piece of paper that is large enough to accommodate the mushroom cap. While any type of paper can be used, wax paper or aluminium foil is commonly recommended. Wax paper provides a smooth surface that can easily be sterilised with rubbing alcohol, preventing bacterial contamination. Aluminium foil can also be used and sterilised by holding it over a flame.
• Colours: Mushroom spores come in a variety of colours, most commonly white and black. To ensure the spores are visible, it is recommended to use white and black paper side by side. This way, regardless of the spore colour, they will show up in contrast to the paper.
• Container: A glass container or bowl that can be inverted over the mushroom is necessary to prevent the spores from drying out and contain their spread.
• Mushroom: Select a mature mushroom with visible gills or pores, ensuring it is firm and not mushy. Check that the gills are moist as dry gills may indicate old age and reduced ability to release spores.

Once you have gathered your materials, follow these steps to prepare the surface:

• Sterilise the paper: If using wax paper, wipe it down with 70% rubbing alcohol. For aluminium foil, hold it over a flame to sterilise. This step is crucial to prevent bacterial growth that may interfere with your spore print.
• Wear protective gear: To maintain a sterile environment, consider wearing gloves. If using aluminium foil, heat-proof gloves are recommended.
• Prepare the mushroom: Remove the stem from the mushroom, ensuring you have access to the gills or pores. If there is a partial veil obstructing the gills, gently remove it. Check that the gills are moist and the mushroom is in good condition.
• Set up the surface: Place the mushroom cap, gill-side down, onto the centre of the paper. If using aluminium foil, you may need to create a small indentation to ensure the mushroom stays in place. Ensure the mushroom is not pressed down too firmly to avoid crushing it.
• Add moisture: To encourage spore release, add a single drop of water to the top of the mushroom cap. Be careful to not soak the mushroom, as this can damage the spores. Use sterilised water if maintaining a pure culture is important.
• Cover the mushroom: Place the glass container or bowl over the mushroom to create a humid environment. This will prevent the mushroom from drying out and help contain the spores.

By following these steps, you will have successfully prepared the surface for harvesting mushroom spores through spore printing. With patience, you will soon see the spores drop onto the paper, creating an intricate pattern that is nature's marvel.

Extracting the spores

Selecting the Mushroom

Begin by choosing a mature mushroom specimen with apparent gills. It is recommended to select edible mushrooms, readily available at local grocers. Ensure the mushroom is healthy, firm, and not mushy or wet. Check that the gills are moist, as dry gills are less likely to release spores.

Preparing the Surface

Place two pieces of paper, one white and one black, side by side. Sterilize the surface using wax paper or aluminium foil wiped down with 70% rubbing alcohol or held over a flame. This step prevents bacterial contamination. If desired, wear heat-proof gloves for added protection.

Positioning the Mushroom

Remove the stem from the mushroom, being careful not to damage the gills. If you wish to keep the stem attached, cut a hole in an index card, place it over a bowl, and insert the stem through the hole so the cap rests on the paper. Gently flip the mushroom so that the gills face down, and place it onto the prepared surface. If your mushroom has pores instead of gills, ensure the pore side is down.

Encouraging Spore Release

Add a single drop of water to the top of the mushroom cap to keep it moist and encourage spore release. Be careful not to soak the mushroom, as this may damage the spores. If using water, ensure it is sterilized by boiling and cooling, or pressure cooking at 15 psi for 15 minutes. Alternatively, you can use a sterile syringe to drop a mixture of spores and water onto a microscope slide for a clearer view.

Observing the Spore Print

After a few hours, carefully lift the mushroom to reveal the spore print on the paper. Spores typically resemble dirt or dust and vary in colour, including brown, black, white, red, and yellow shades. If desired, leave the mushroom in place for a longer period to collect more spores.

Storing the spores

Once you have harvested the spores, you can store the spore prints for a while as you work out the ins and outs of cultivation. The prints can be made on paper or glass slides. If you have used paper, you can fold the prints and store them carefully. If you have used a glass slide, you can wash the slide with soapy water or put it in a pressure cooker on a dry cycle at 15 psi for 15 minutes.

If you are storing spores in a syringe, make sure that the syringe is sterile. Sterile syringes can be purchased online from a vendor.

If you are storing spores in a solution, you can mix the spores with water and squirt them around your yard and planter beds where composted material is.

If you are storing spores in a grain spawn, you can mix the grain spawn with a substrate once the grain spawn is colonized and free of contamination.

If you are storing spores in agar, you can skip the grain step and isolate growth through multiple agar steps.

Frequently asked questions