Techniques for outdoor mushroom cultivation

 Step 1 : Preparing the growing location

• Straw mushrooms can be cultivated in shade or direct light locations, such as on field ground or seedbed ground. The chosen grown site must have good drainage to manage watering or rainfall effectively.
• The soil for cultivating straw mushrooms should be treated with lime at a rate of 5 kg/100 m2 (or 300-500 kg/ha)

Step 2: Straw source

The straw source can be in bale loose form. The straw source must be disease-free, not affected by pesticides, not contaminated with salinity and white mold, and not rotten due to rain.

Step 3: Preparing rice straw

• Prepare a straw soaking tank, placing it near the composting area for convenience.
• Use waterproof tarpaulin to construct the soaking tank with the size depending on actual conditions.
• The ground for the tank must be flat, without sharp trees or objects that could tear the walls of the tank.

Prepare lime water:

• Add water, to about 20cm high, then add lime. Stir well and use pH paper to test (aiming for a pH of 13-14). Usually, about 5 kg of lime should be added to 1 m3 of water
• Note: When adding lime to water, the water will become very hot, which can harm your skin. Therefore, you should let the water cool down gradually.

After soaking the straw for approximately 10 minutes, remove and drain it. The straw will appear bright yellow after being soaked in lime water.

Step 4: Stacking and turning

• Stack the straw into layers and alternative with burned lime
• Water to add moisture to the compost pile
• Place banana trees in the middle of the compost pile to create ventilation for the compost pile
• The amount of straw used is ≥ 100kg, the size of the compost pile is about 1.2 – 1.5m high, about ≥ 1.5m wide and can be more than 1.5m long.
• Use waterproof tarpaulin to cover the compost pile, there should be ventilation holes on the compost pile.

• Monitor humidity levels and add water as necessary, ensuring the temperature remains 60 – 70°C.
• After 7 and 17 days of composting, turn the pile for the first and second times, rotating from the inside out and from the outside in.

Step 5: Preparing the mushroom spawn

• The spawn is rice husk spawn, so choose bags of spawn with evenly white silk and a pleasant smell.
• The spawn is separated and mixed with mycelium stimulating yeast at the recommended ratio. Or mix with vermicompost, dose of 70-160g and mushroom mycelium stimulating ingredients as recommended.

Step 6: Putting compost in bed

• After composting for 16-18 days, the compost is placed in a bed.  The size of the compost bed should be 35-40 cm wide and 35 cm high. Straw is taken from the compost pile, rolled, and arranged into lines.
• Following this, a layer of spawn is spread in the middle of the line (approximately 160g/m of line).
• Then the surface is covered with another layer of straw.
• The compost bed is then prepared and watered. Using both hands, the compost bed is stroked and tightly compressed. Subsequently, the compost bed is exposed to direct sunlight for 4 days.

Caution:  Using the tarpaulin cover the compost bed is used in the rain; make sure the ventilation is good. Incase it is windy arrange the compost line to avoid the direct wind, the wind flow at the head of the bed.

Step 7: Caring and watering

• After drying in the sun, the bed should be covered with straw, then the cover should be wetted.
• Watering once a day, either in the afternoon at about 4 pm or in the morning (7-8 am), should be done using a shower.

• After covering the straw for 4 or 5 days, check the spread of mycelium and turn the bed cover to limit the mycelium spreading beyond the cover layer.
• On the 7th or 8th day, when the mycelium spreads evenly, begin watering for mushroom growth. About 2 days later, the pins will start appearing.

Step 8: Harvesting

• The time from sowing spawn to harvesting is about 12 days. Harvest twice a day, in the morning (at 5-6 am) and in the afternoon (at 17-18 pm).
• There are 2 harvests. The 1st harvest is within 4 days. Afterwards, take care of the mushroom bed, and approximately 5-6 days later, the mushrooms will appear.
• How to harvest mushrooms:  Gently rotate the mushroom to separate it from the compost bed. Do not leave the mushroom feet on the compost bed, because the mushroom feet will rot and damage the affected mushroom buds. After harvesting, cover the compost bed.

Step 9: Cleaning after mushrooms cultivation

• After harvesting the mushrooms, the substrate can be composted to create organic fertilizer for plants.
• Use burnt lime to disinfect the growing area and leave it in the sun for at least 1 month before growing the next crop.