What Is the External Nutrition Bag Method in Commercial Morel Cultivation?
The External Nutrition Bag (ENB) method is a morel cultivation technique in which a separate bag of nutritive substrate is placed in contact with the colonized growing bed, giving the mycelium a controlled extra food source before fruiting. It was invented in Sichuan, China, in 2000 by the Sichuan Morel Research Institute and is now a practical foundation of commercial Morchella farming. Instead of loading all nutrition into the base substrate, growers add it in a discrete, measurable bag that can be timed, replaced and scaled.
The method matters because morel cultivation is not simply a matter of adding more nutrients. The base substrate supports initial colonization, while the external bag allows the grower to separate colonization from supplementation. That separation makes the crop easier to manage: bags can be placed when the mycelium is ready, removed when spent, and checked for contamination without disturbing the whole bed. Bag fill weight, moisture and contact with the bed all affect how evenly the supplement is used.
A practical ENB workflow usually looks like this:
• Prepare a clean base substrate and inoculate at the right spawn dose. Institute guidance uses one spawn tube for 667 m² (1 mu), but bed design and local conditions should set the final rate.
• Wait for the mycelium to establish in the bed before placing ENB bags. Placing them too early can invite competition from weed moulds.
• Place bags evenly and ensure firm contact with the colonized surface. Contact is the point of the method: the mycelium must be able to grow into the bag.
• Keep fill weight consistent. The 4th-generation ENB Automatic Nutrient Bagging Machine fills 300 g to 1,000 g bags at 30–50 bags/min, or 1,800–3,000 bags/hr.
• Monitor climate and remove spent or contaminated bags. In indoor systems, IoT smart cabins maintain 4–28 °C, 70–98% RH and 400–2000 ppm CO2 with remote monitoring.
For small trials, hand-filled bags are enough to learn the timing. As the planted area grows, bagging quickly becomes a bottleneck. A machine that replaces 15–25 workers, runs on 220V/50Hz/1.5 kW and weighs about 380 kg changes the labour equation, but the greater benefit is consistency. Uniform bag weight and fill density make the method easier to repeat from plot to plot and season to season.
Common mistakes include placing bags too early, allowing bags to dry out or become waterlogged, using dirty or damaged bag material, and over-supplementing in the hope of a bigger crop. ENB is not a substitute for clean substrate, healthy spawn or correct climate management. If substrate is prepared in-house, pair the method with proper sterilization; the institute's high-pressure autoclaves run at 105/115/121 °C and up to 76 m³, with 304/316 stainless steel options.
The method fits both outdoor fields and indoor systems. Outdoors, ENB is usually combined with shade netting and irrigation scheduling; indoors, it is combined with temperature, humidity and CO2 control. The Sichuan Morel Research Institute supports growers through its Online Morel Cultivation Masterclass in English (Class A $5,000 / Class B $10,000), turnkey farm design for 1–50+ ha, and equipment exports to more than 25 countries, including projects in France, Turkey and Spain.
The short answer is that the External Nutrition Bag method turns supplementary nutrition into a managed step rather than a single upfront guess. Used with clean substrate, reliable spawn and consistent bag filling, it gives commercial morel growers a clearer way to control when and how the crop receives extra nutrition. More details are available at www.cn-localfoods.com or by contacting [email protected].