Remove the block from the shipping box as soon as possible. Then, unfold the top of the bag, making room for air space. It's also important to check and confirm that the filter patch is not obstructed. This will help the organism breathe and continue to thrive until you are ready to grow your fruiting block!

Chestnut mushrooms are slow-growing and richly colored, with firm texture and nutty flavor. While they can be grown outdoors, they require a bit more patience and care than faster-fruiting species.

How to initiate fruiting outdoors:

• Wait for color change: Allow the block to begin turning orange within the bag before initiating fruiting. This is a sign the mycelium is mature and ready.
• Cold shock: Place the unopened bag in the refrigerator for about 8 hours before introducing it to the outdoor environment. This cold shock can help trigger pinning.
• Pick a shady spot: Find a well-ventilated area with indirect light—beneath trees or along a north-facing wall works well.
• Bury the block: Remove the plastic bag entirely from your block. Bury the block completely, adding about 1" of soil or mulch on top.
• Maintain moisture: Mist regularly around the block to maintain high humidity. Be consistent—chestnuts are slow to pin and require steady conditions.

Temperature & humidity:

• Chestnuts prefer cooler temperatures (ideally 55–65°F), so they’re better suited to spring and fall grows in most regions.
• Avoid overly hot or dry conditions, which can stall growth.
• These mushrooms are more sensitive to environmental shifts, so try to protect them from wind, sun, and dramatic temperature swings.

Special considerations:

• Fruiting may take several weeks—be patient and keep humidity high during the wait.
• The block may produce a single large flush rather than multiple smaller ones.
• Pigment from the caps can stain lighter-colored mushrooms or surfaces if placed nearby.

Harvesting:

• Harvest chestnuts before the veil breaks—this means the caps will still be rounded or cupped.
• Delaying harvest can shorten shelf life and cause mushrooms to lose their firm texture.
• Use a clean knife or gentle twist to remove clusters without damaging the block.

Chestnuts reward patience with a beautiful and satisfying harvest—rich in color, flavor, and texture.

• Primordia -  The earliest recognizable stage of fruitbody development. Also known as “baby mushrooms” or “mushroom pins.”
• Fruitbody - A fully grown mushroom, the reproductive structure of the organism in which the spores are produced.
• CO2 sensitivity - When CO2 levels are too high, yields will decrease, stems will become long and stringy, caps will be small, and/or growth will halt.

If you don't plan to use immediately, you can refrigerate your block for up to 6 months.

"5 of the Best Chestnut Mushroom Recipes"

For those who enjoy the distinct nutty flavor of chestnut mushrooms, we recommend frying them up with butter and garlic or adding them to your favorite creamy soup or pasta dish. As with other mushrooms, chestnut mushrooms require thorough cooking. However, given their lower moisture content, they do not require “sweating” in the pan.

If you’re going to consume home-grown mushrooms, make sure to cook your fresh mushrooms thoroughly with heat. If it is your first time eating this species, it is best to start with a small amount to check for allergies, even if cooked.

Mushrooms grow spores as they develop. This is a natural means of reproduction. This is when people with allergies or compromised immune systems may want to consider putting fruiting mushroom kits outdoors or in a well-ventilated area. Spores in mushrooms sometimes cause respiratory irritation. In rare cases, spores may also cause irritation for some non-allergic or non-immunocompromised mushroom growers. If you are one of them, it is recommended to reduce the overall spore load by harvesting mushrooms while they are still in their younger growth stages.