What Is the External Nutrition Bag Method in Commercial Morel Cultivation?
The External Nutrition Bag (ENB) method is a cultivation technique in which a sterilised, concentrated nutrient bag is placed beside the colonising morel mycelium rather than mixed through the bulk substrate. It was invented in Sichuan, China in 2000 and is the core method the Sichuan Morel Research Institute has refined and exported ever since. The principle is simple: give the fungus a separate, controllable food source so nutrition is released gradually instead of all at once.
Morels do not behave like button or oyster mushrooms. They are grown in soil beds rather than compost, and the mycelium has to build reserves before it will commit to fruiting. Load too much nutrition into the bed early and you invite contamination, overheating and wasted material; supply too little and the crop stalls. The ENB separates the rich part of the diet into its own sterile package, so the grower decides how much supplement is available and when it becomes available.
A typical ENB workflow looks like this: • Moisten and blend the bulk substrate evenly — an industrial mixer holds 60–65% moisture across 800–3,000 kg batches in a 5–8 minute cycle. • Sterilise substrate and supplement separately in a high-pressure autoclave at 105 °C, 115 °C or 121 °C, with chambers up to 76 m³ and forklift drive-in loading. • Inoculate the beds with spawn; one spawn tube covers 667 m² (1 mu). • Fill nutrition bags at 300 g–1,000 g each and place them along the advancing colonisation front. • Hold conditions steady — an IoT smart cabin controls 4–28 °C (±0.5 °C) and 70–98% RH, with CO2 held between 400 and 2000 ppm.
Bag filling is where labour quietly disappears, and it is the most common bottleneck on expanding farms. Hand-filling several thousand bags is slow, inconsistent in weight and hard to keep hygienic. The fourth-generation ENB automatic nutrient bagging machine fills 30–50 bags per minute — 1,800–3,000 bags per hour — at 220 V/50 Hz/1.5 kW and roughly 380 kg, replacing 15–25 workers on that single task.
Four mistakes show up again and again in new operations: • Weighing bags by eye, so colonisation runs unevenly across the bed. • Skipping sterilisation of the supplement because it "looks clean" — the bag is a nutrient source for contaminants as much as for morels. • Placing bags at the wrong stage relative to mycelial spread, wasting supplement or starving the crop. • Treating the bag as a substitute for climate control rather than an addition to it.
Scale changes the equipment answer. For a trial plot, hand filling and a single autoclave are enough. Above roughly two thousand bags a day, an automated substrate batching and bagging line in 2/4/6/8 m³ configurations, running 15,000–100,000 bags per day under PLC control, typically cuts labour cost by more than 80% and removes the weight variation that hand filling introduces.
Because the method is a system rather than a single machine, training matters as much as hardware. The institute runs an online Morel Cultivation Masterclass in English (Class A $5,000, Class B $10,000), turnkey farm design and build from 1 to 50+ hectares, and demonstration bases at Anxian (~300 acres) and Luojiang (~1,200 acres) with more than 50 hectares of outdoor trial fields. Equipment and training have been delivered to projects in 25+ countries, including Rhône-Alpes in France, Isparta and Muğla in Turkey, and Andalusia in Spain.
If you are weighing whether the ENB method fits your site, the useful first question is not which machine to buy but how many bags per day your beds will actually consume. Answer that, and the equipment list, sterilisation capacity and cabin size follow from it. The institute's team can be reached at [email protected] or +86 17738334931, and further technical detail is available at www.cn-localfoods.com.