What Is the External Nutrition Bag Method in Commercial Morel Cultivation?
The External Nutrition Bag (ENB) method is a morel cultivation technique in which sterilized bags of supplementary nutrition are placed in the soil bed beside the running morel mycelium, so the fungus can draw extra food through the long fruiting window instead of depending only on the base substrate. It was invented in Sichuan, China, in 2000 and has since become the working framework behind most large-scale Morchella farms in that region. Put simply: the bag is not a container for growing mushrooms — it is an external food source for mycelium that is already established in the soil.
In practice, the sequence matters. Spawn is first run into prepared, moistened beds; once the mycelium has spread through the soil, bags are laid at intervals along the bed and lightly covered. The mycelium grows into the bag surface and colonizes its contents from the outside in, effectively using the bag as an external digestive organ. Because the contents are sterilized before colonization begins, the morel meets that food source without competing organisms already established inside it — a key difference from broadcasting supplements loose into the bed.
That separation is the method's real advantage. Loose or mixed-in nutrition is available to weed moulds and competitor fungi at the same moment it is available to the morel, and it breaks down whether or not the crop needs it. An external bag keeps the nutrition spatially contained, releases it over a longer period, and can be lifted out once spent, leaving the bed clean for the next cycle. On farms running several cycles per year, that removability is as valuable as the feeding itself.
Consistency is where the method succeeds or fails at scale. Bag fill weight typically ranges from 300 g to 1,000 g depending on bed design and target nutrition load, and uneven fill produces uneven colonization across the field. Hand-filling several thousand bags a day is where most small operations stall, which is why the Sichuan Morel Research Institute's fourth-generation ENB bagging machine runs at 30–50 bags per minute (1,800–3,000 bags per hour), handles 300 g–1,000 g per bag on 220V/50Hz/1.5 kW, weighs roughly 380 kg, and is designed to replace 15–25 workers on the filling line.
Sterility upstream of the bag matters just as much. Substrate and bag contents are typically treated in a high-pressure autoclave at 105 °C, 115 °C or 121 °C, with chamber sizes up to 76 m³ and forklift drive-in loading; 304 or 316 stainless construction is available where washdown and corrosion resistance are priorities. Downstream, fruiting conditions can be held in a 20FT or 40FT IoT smart cabin at 4–28 °C (±0.5), 70–98% relative humidity and CO2 between 400 and 2,000 ppm, with remote monitoring, while outdoor beds rely on UV-stabilized shade netting at 75%, 85% or 90% density.
A practical checklist for anyone adopting the method:
• Run spawn before placing bags — mycelium should already be active in the bed, otherwise the bag sits uncolonized and invites contamination. • Standardize fill weight and moisture batch to batch; record it, because colonization speed tracks fill weight closely. • Sterilize thoroughly and cool before inoculation — a bag that is warm inside is a competitor's head start. • Place bags at consistent spacing and depth, and remove spent bags promptly at the end of the flush.
Spawn planning is straightforward at this scale: one spawn tube inoculates 667 m² (one mu). For reference, the institute's demonstration and manufacturing bases cover roughly 300 acres at Anxian and 1,200 acres at Luojiang, alongside more than 50 hectares of outdoor demo fields and a 12,000 m² equipment workshop — the setting in which the ENB method and its machinery were refined before export to more than 25 countries, including projects in France's Rhône-Alpes, Turkey's Isparta and Muğla provinces, and Andalusia in Spain.
Growers evaluating the method usually need three things in parallel: reliable bag production, credible sterilization, and climate control that keeps the fruiting window stable. Sichuan Morel Research Institute supplies all three, plus spawn, agronomy training and turnkey farm design from 1 to 50+ hectares; details are at www.cn-localfoods.com or via [email protected] and +86 17738334931.