How to Grow Fee's Polypore (Fomitopsis feei)
How to Grow Fee's Polypore (Fomitopsis feei)
Fee's Polypore (Fomitopsis feei (Fomitopsis feei)) is grown by inoculating sterilized cracked corn grain spawn with liquid culture, colonizing that grain at 82–86°F, then transferring it into a supplemented hardwood sawdust mushroom substrate block for continued colonization and a fruiting attempt. Fomitopsis feei (Fomitopsis feei) has never been reliably fruited in home mushroom cultivation — your block will very likely colonize fully, but whether it pins depends on environmental variables that remain undocumented for this species, so every grow you complete advances the collective knowledge of Fomitopsis feei (Fomitopsis feei) cultivation.
Fee's Polypore (Fomitopsis feei): Indoor Sawdust Block Method
Fee's Polypore Equipment — Indoor Sawdust Block
| Item | Spec / Notes |
|---|---|
| Liquid culture syringe | Fomitopsis feei liquid culture — 10–12 cc per 3 lb grain bag, 20–25 cc per 5 lb grain bag. |
| Cracked corn | 1 lb dry per standard batch; whole oats or rye berries acceptable substitute. |
| Pressure cooker / canner | Must hold 15 PSI; digital gauge preferred. |
| Mushroom grow bags with filter patch | 0.2 micron filter — Medium 0.2 micron grow bags; large bags for substrate blocks. |
| Hardwood sawdust pellets | Oak, maple, or beech; 4 lbs per 5 lb substrate block (fuel pellets from hardware store work well). |
| Wheat bran or rice bran | ¾ lb per 5 lb block; available at feed stores or brewing supply shops. |
| Corn meal | ¼ cup per 5 lb block. |
| Gypsum | 2 tbsp per 5 lb block; available at garden centers. |
| Hydrated lime | 1 tbsp per 5 lb block; raises pH; available at garden centers. |
| Isopropyl alcohol (70%) | For sterilizing injection ports and work surfaces. |
| Still-air box or flow hood | For inoculation and grain-to-substrate transfer. |
| Seedling heat mat with thermostat | For maintaining 82–86°F colonization temperature. |
| Hygrometer and humidity source | For fruiting attempt: target 85–95% RH. |
| Spray bottle | For surface misting during fruiting attempt. |
| Sharp knife | For harvesting bracket fruiting bodies if pinning occurs. |
- 1 lb dry cracked corn (or whole oats / rye berries as substitute)
- Water for soaking and simmering
- Mushroom grow bags with 0.2 micron filter patch
- Pressure cooker capable of holding 15 PSI
Scale-up: 3 lb grain → 3 grow bags | 5 lb grain → 5 grow bags
Rinse the cracked corn, then submerge it in cold water and soak for 12–18 hours at room temperature. After soaking, drain the corn and simmer it in fresh water for 15–20 minutes, until kernels just begin to split — stop before they burst open. Drain and spread on a clean surface for 15–20 minutes, or until the surface feels dry to the touch with no standing water visible. Load the surface-dry grain into grow bags, leaving 3–4 inches of headspace, and seal each bag. Place the sealed bags in your pressure cooker and sterilize at 15 PSI for 90 minutes. After sterilization, remove bags and allow them to cool completely to room temperature — this takes 8–12 hours; never inoculate warm grain.
- Fomitopsis feei liquid culture syringe — 10–12 cc per 3 lb bag or 20–25 cc per 5 lb bag (higher volume compensates for this species' slow colonization rate)
- Alcohol lamp or lighter for flame-sterilizing needle
- 70% isopropyl alcohol wipes
- Still-air box or flow hood
Shake your Fomitopsis feei (Fomitopsis feei) liquid culture syringe vigorously for 30 seconds to evenly suspend the mycelium. Flame-sterilize the needle until red-hot, let it cool for 5 seconds, then wipe the injection port with an isopropyl alcohol wipe. Working inside your still-air box or flow hood, inject the liquid culture through the filter patch or self-healing injection port directly into the cooled grain. Distribute the LC volume evenly across the bag by injecting at two or three points if possible. Seal the injection point with micropore tape if using a filter patch. Out-Grow carries Fomitopsis feei (Fomitopsis feei) liquid culture ready to inject: Fee's Polypore Liquid Culture.
- Seedling heat mat with thermostat set to 82–86°F
- Dark location or cardboard to block light during colonization
Place inoculated grain bags on the heat mat in a dark location — darkness measurably improves mycelial density in Fomitopsis feei (Fomitopsis feei). Maintain 82–86°F consistently; below 75°F, growth slows dramatically and the contamination window expands. Shake bags gently once white mycelium is visible on 20–30% of the grain to distribute growth points evenly. Expect grain jars to reach full colonization in 21–28 days at optimal temperature — significantly longer than oyster or shiitake mushroom spawn. Out-Grow also carries sterilized grain spawn bags ready to inoculate if you want to skip Steps 1–3: Sterilized Grain Spawn Bags.
- 4 lbs hardwood sawdust pellets (oak, maple, or beech — rehydrate fuel pellets before use)
- ¾ lb wheat bran or rice bran
- ¼ cup corn meal
- 2 tbsp gypsum
- 1 tbsp hydrated lime
- Approximately 5½ cups water (add gradually to reach field capacity)
- Large mushroom grow bags with 0.2 micron filter patch
Scale-up: 3 blocks — multiply all amounts by 3 | 5 blocks — multiply all amounts by 5
If using hardwood fuel pellets, rehydrate them first by adding water and allowing them to break down into sawdust — this takes about 15 minutes. Combine the rehydrated sawdust with bran, corn meal, gypsum, and lime in a large mixing container. Add water gradually, mixing as you go, until the mushroom substrate reaches field capacity: a firm squeeze should produce 1–2 drops of water, not a stream. Load the mixed mushroom substrate into grow bags, filling to about 5–6 lbs total, and seal. Sterilize at 15 PSI for 150 minutes (2.5 hours) — the additional sterilization time compared to grain is required because Fomitopsis feei (Fomitopsis feei) colonizes slowly and competes poorly with contaminants. Cool completely before proceeding — at least 8 hours. Out-Grow also carries ready-to-inoculate hardwood substrate bags: Wood-Based Inoculate and Wait Mushroom Substrate.
- Fully colonized Fomitopsis feei grain spawn bags (use within 1–2 weeks of full colonization for maximum vigor)
- Cooled sterilized substrate bags
- Still-air box or flow hood
- 70% isopropyl alcohol for surface sanitation
- Spawn rate: 15–20% by weight — approximately ¾–1 lb colonized grain spawn per 5 lb substrate block
Scale-up: 3 blocks require 3 grain bags of spawn | 5 blocks require 5 grain bags of spawn
Before opening the grain bag, squeeze and knead it thoroughly until the grain separates completely into individual kernels — no clumped masses. Sanitize all surfaces and your hands with 70% isopropyl alcohol. Working inside your still-air box or flow hood, open both the grain bag and the substrate bag. Scatter the broken grain spawn evenly across the top surface of the substrate before mixing — this prevents pockets of grain concentrating in one area. Mix thoroughly until no isolated clusters of grain remain visible against the substrate. Seal the bag. Never inoculate warm mushroom substrate — if the substrate is above room temperature, wait until fully cool.
- Heat mat with thermostat set to 82–86°F
- Dark location or cardboard covering to block light
Place spawned substrate blocks on the heat mat in a dark location. Maintain 82–86°F — this is the peer-reviewed optimal temperature range for Fomitopsis feei (Fomitopsis feei) mycelium. Below 75°F, mycelial growth stalls sharply. Do not introduce fresh air exchange (FAE) during colonization — sealed bags self-regulate humidity and the high CO₂ environment supports mycelial growth at this stage. Expect 45–90 days for a 5 lb Fomitopsis feei (Fomitopsis feei) block to fully colonize — this is 2–3 times longer than oyster or shiitake mushroom blocks, and is normal for polypore species. After the surface appears 100% white, wait an additional 7–10 days to allow mycelium to consolidate throughout the interior of the block.
- Fruiting chamber or humidity tent capable of 85–95% RH
- Hygrometer to confirm RH at the block surface
- Temperature drop capacity: target 68–72°F (down from 82–86°F colonization temp)
- Light source: 12 hours of indirect light daily (try blue-spectrum LED)
- Fresh air exchange: 4–6 air exchanges per hour
- Spray bottle for misting
Remove the block from its bag or cut a fruiting hole in the top surface. Drop the temperature to 68–72°F and introduce fresh air exchange — oxygen levels closer to ambient appear necessary for polypore pinning. Maintain 85–95% RH at the block surface; if your room humidity reads 90% but pins do not develop within 4 weeks, tent the block with a clear plastic bag vented at the bottom and mist the interior 2–3 times daily to create a microclimate above 95% RH. Provide 12 hours of indirect light daily. Fomitopsis feei (Fomitopsis feei) pins have not been documented in controlled cultivation — if visible primordia (small white knobs or bumps) develop on the block surface, maintain all conditions without disruption. If no pins appear after 4–6 weeks of consistent fruiting conditions, proceed to the troubleshooting section below for next steps specific to Fomitopsis feei (Fomitopsis feei).
- Sharp, clean knife
- 70% isopropyl alcohol wipe for knife blade
Harvest Fomitopsis feei (Fomitopsis feei) bracket fruiting bodies when the margin of the bracket has stopped expanding and the pore surface on the underside is fully formed but still white — harvest before any white powder (spore accumulation) appears around the grow area. Cut the bracket at its base with a clean knife; do not twist or pull, as the attachment point on polypore fruiting bodies is significant and pulling risks tearing the substrate. Leave 1–⅛ inch of the base attached rather than cutting flush to the surface. After harvest, mist the cut site heavily and resume fruiting conditions. Rest the block for 10–14 days at 80%+ RH with reduced FAE before a second flush attempt. Mist the block surface daily rather than dunking — fully waterlogging a polypore mushroom substrate block risks structural breakdown. Discard the block if mycelium yellows, the block shrinks significantly, or a sour smell develops.
Fee's Polypore (Fomitopsis feei) Troubleshooting
Common Problems Growing Fomitopsis feei — Contamination and Colonization Failures
The most frequent contamination threat across all stages of Fomitopsis feei (Fomitopsis feei) mushroom cultivation is Trichoderma green mold. Because Fomitopsis feei (Fomitopsis feei) mycelium colonizes slowly — grain spawn takes 21–28 days and sawdust mushroom substrate blocks can take 45–90 days — the window for competing contaminants is long. Trichoderma appears as bright green powdery patches that spread concentrically and produce a sour smell; it spreads faster than Fomitopsis feei (Fomitopsis feei) white mycelium and must be isolated immediately when spotted. Bacterial wet spot (gray-brown slimy patches with a rotten odor, most often at the bottom of grain containers) indicates insufficient sterilization or grain that was too wet when loaded. Aspergillus black mold appearing near filter patches signals pre-sterilization contamination or cracked container walls. Any green or black contamination in a grain bag warrants immediate discarding — the risk of contaminating adjacent bags outweighs any benefit of attempting to salvage. For cobweb mold on the mushroom substrate surface — a wispy, translucent gray growth spreading much faster than Fee's Polypore mycelium — a direct spray of 3% hydrogen peroxide can halt spread while leaving Fomitopsis feei (Fomitopsis feei) mycelium intact.
Colonization stalls at 30–50% surface coverage are the second most common problem in Fomitopsis feei (Fomitopsis feei) mushroom cultivation. The cause is almost always temperature drop — Fomitopsis feei (Fomitopsis feei) requires 82–86°F throughout the entire colonization period, and ambient room temperature drops below 75°F will halt progress. If colonization stalls with no visible contamination, increase temperature immediately using a seedling heat mat with a thermostat. Other causes include insufficient spawn rate (use 15–20% by weight minimum — higher than the 10–12% typical for oyster mushroom spawn due to this species' slow growth), mushroom substrate moisture content below 50% (inject 20–30 cc of sterile water into stalled areas using a syringe if the substrate feels crumbly), and aged grain spawn used more than 2 weeks after full colonization. If liquid culture shows no visible mycelial growth in grain after 7–10 days, test a small amount on an agar plate to confirm the liquid culture syringe is viable before committing more grain to another attempt.
The most challenging scenario specific to Fomitopsis feei (Fomitopsis feei) cultivation is a fully colonized block that does not pin after 4–6 weeks of standard fruiting conditions. This is not a technique failure — it reflects the current state of documentation for this experimental species. Fomitopsis feei (Fomitopsis feei) has not been reliably fruited in home mushroom cultivation, and individual wild-collected isolates may require environmental cues — specific light wavelength, seasonal temperature cycling, soil microbes, or tree-compound signals — that are absent in sterile indoor cultivation. If standard fruiting conditions (68–72°F, 85–95% RH, 12-hour light cycle, 4–6 air exchanges per hour) produce no pins after 6 weeks, try a temperature shock: place the block in a 50–55°F environment for 48 hours, then return it to 68–72°F. Try blue-spectrum LED lighting if you have been using standard white light. Consider transitioning the block outdoors by burying it in a shaded garden bed or wood chip mulch — wild environmental conditions may provide the missing fruiting trigger. Photograph your setup and document your parameters; negative results for Fomitopsis feei (Fomitopsis feei) cultivation are genuine contributions to the community's understanding of this species. Fruiting is not reliably documented for home cultivation, and every documented attempt — successful or not — helps narrow what conditions matter.
How to Grow Fomitopsis feei
Questions and Answers About Fomitopsis feei Cultivation
Q. Can Fomitopsis feei be fruited indoors?
A. As of 2026, no peer-reviewed or hobbyist sources document reliable indoor fruiting of Fomitopsis feei (Fomitopsis feei). Mushroom cultivation of Fee's Polypore is well-established through the mycelial stage — liquid culture to grain spawn to sawdust mushroom substrate colonization — but pinning conditions for this species remain undocumented. The closest reference point is Fomitopsis pinicola, a related polypore with documented indoor fruiting using supplemented sawdust mushroom substrate blocks, temperature drops, and high humidity. Applying similar fruiting protocols to Fomitopsis feei (Fomitopsis feei) is a reasonable experimental approach, but cultivators should set expectations accordingly: colonization is the reliable outcome; fruiting bodies are not guaranteed.
Q. How long does Fomitopsis feei grain spawn take to colonize?
A. At optimal colonization temperature of 82–86°F in darkness, a quart-sized grain spawn container inoculated with Fomitopsis feei (Fomitopsis feei) liquid culture typically reaches full colonization in 21–28 days. Sawdust mushroom substrate blocks take considerably longer — 45–90 days at optimal temperature. This is 2–3 times the colonization time of gourmet species like oyster mushroom grain spawn. Temperature is the most critical variable: dropping below 75°F will significantly slow mycelial growth and extend the contamination window, the primary threat to successful Fomitopsis feei (Fomitopsis feei) mushroom cultivation.
Q. What does healthy Fomitopsis feei mycelium look like vs contamination?
A. Healthy Fomitopsis feei (Fomitopsis feei) mycelium is white, dense, and cottony, with a radiating growth pattern from inoculation points and no sectoring or irregular color variation. The liquid culture syringe should show white mycelial particles suspended in the liquid after shaking. Contamination signatures are distinct: Trichoderma green mold appears as bright green powdery patches — unmistakable against white Fomitopsis feei (Fomitopsis feei) mycelium — and spreads concentrically with a sour smell. Bacterial wet spot looks gray-brown, slimy, and translucent with a rotten odor, typically pooling at container bottoms. Aspergillus presents as black or dark gray powdery colonies near air-exchange filters. Cobweb mold is wispy and translucent — far thinner and faster-growing than Fee's Polypore mycelium. If liquid culture appears yellowed or shows no visible particles after shaking, test viability on an agar plate before using it to inoculate grain spawn.
Q. Why won't my Fomitopsis feei block pin after full colonization?
A. Non-pinning on a fully colonized Fee's Polypore block is the most common outcome in current home mushroom cultivation attempts, and it is not necessarily a technique error. Fomitopsis feei (Fomitopsis feei) fruiting requirements are undocumented — this species may need specific environmental signals (light wavelength, microbial signals from soil or wood, seasonal temperature cycling) that sterile indoor mushroom cultivation cannot replicate. After confirming standard fruiting conditions (68–72°F, 85–95% RH, 12-hour indirect light cycle, 4–6 fresh air exchanges per hour) have been maintained for 4–6 weeks without result, try a 48-hour temperature shock at 50–55°F before returning to fruiting conditions, experiment with blue-spectrum LED lighting, or transition the colonized mushroom substrate block outdoors to wood chip mulch or a shaded garden bed. Document your results with photos and parameter logs — the cultivation knowledge of this species advances with every shared attempt.
Q. What mushroom substrate does Fomitopsis feei require, and what should be avoided?
A. Fomitopsis feei (Fomitopsis feei) is a brown-rot hardwood polypore, and its mushroom substrate should reflect that ecology: a hardwood sawdust base (oak, maple, or beech) supplemented with wheat bran, corn meal, gypsum, and a small amount of lime to adjust pH. Straw-only mushroom substrate is not appropriate — Fee's Polypore preferentially degrades lignin in hardwood, and straw lacks the appropriate lignin profile, resulting in stalled colonization and contamination takeover. Manure-based mushroom substrate is also incompatible — Fomitopsis feei (Fomitopsis feei) is a wood-decay fungus, not a coprophilous species. Softwood sawdust (pine, fir, cedar) should be avoided, as resinous compounds in conifers may inhibit mycelial growth. Sterilization is required rather than pasteurization: because grain spawn and sawdust mushroom substrate blocks colonize slowly, any viable competing organisms that survive pasteurization will outcompete Fomitopsis feei (Fomitopsis feei) over the long colonization window.
Q. How should I store Fomitopsis feei liquid culture before use?
A. Fomitopsis feei (Fomitopsis feei) liquid culture syringes should be stored refrigerated at 34–38°F and used within 6 months of production. Before inoculating grain spawn, shake the syringe vigorously for 30 seconds to evenly resuspend the mycelium — the liquid should show visible white particles after agitation. If the syringe shows no visible mycelium after shaking, or if the liquid has yellowed or turned cloudy in an unusual way, test viability by inoculating a small agar plate before using the liquid culture on grain spawn. Aging or improperly stored liquid culture is one of the leading causes of failed Fomitopsis feei (Fomitopsis feei) grain spawn inoculation — no visible growth in grain 7–10 days after inoculation is the primary symptom of weak or non-viable liquid culture.