Why is casing soil used? There are two main reasons: 1. the Pseudomonas putida bacterium; 2. to regulate evaporation. Mushrooms will not grow without evaporation. The casing soil structure, through the depth of casing and on the surface, is the factor that determines how much water can absorbed and released. This is also known as the water buffer. How can growers influence this effect?
Properties
Casing soil is made up of peat. Peat consist of many small and larger pores which act as communicating structures that affect the flow of water. The very tiny (micro) pores absorb water very slowly, but retain it for a long time. The larger (macro) pores can absorb water faster but release it again very quickly. In good casing soil, both properties are necessary: rapid absorption of water: during mycelium growth and after harvesting, and slow release: during pinhead formation and out grow, and when the mushrooms are harvested.
Air
What is the secret of casing soil? Ensure that the moisture content of the casing soil is good. With “export” casing soil, you have to apply enough water and mix the casing with a loader or bobcat. Ask the supplier for instructions and follow them correctly. This has already been done with casing soil delivered in bulk and ready to use. Casing soil is sensitive to structure loss just before it is applied. If the casing soil is compacted or compressed, the “air” will be squeezed out. This effectively closes off the very crucial micro pores. The casing soil will feel harder. During transport and filling avoid compacting the casing soil too much, for example when using augers, over-filling the hopper on the filler or in front of the levelling axle during filling.
Soft
Casing soil should feel nice and soft. Straight after filling, push your finger into the casing soil. You should be able to plunge your finger in easily and without resistance. Experience will teach you how to feel the difference. A good layer of casing soil after filling is about 6 cm thick. The amount ordered is much less, around 4.5 cm. The rest is air, and these air pockets can largely be filled with the water necessary for the mushrooms to grow!
Mark den Ouden
Mushroom Office
Master class course Mushroom composting and growing is 18 – 23 February, there are still some seats available! Please contact This email address is being protected from spambots. You need JavaScript enabled to view it. ASAP if you want to join! Next course will be 29 April – 4 May.
Longer pre-wetting of straw to preserve structure during mushroom composting
In my 'Pre-wet' blog, I already wrote about the importance of pre-wetting for good mushroom substrate. In this blog, I would like to discuss the structure of straw. I often hear customers say: "We are shortening the pre-wetting time because the structure of the compost is too short." But I disagree with this statement. Why? Read all about it in this blog.
What is the absolute moisture content of the air? Or the enthalpy of the air? More and more growers have a handy app that reads out these values. I always ask: “What do you do with this data?” I don’t always get an answer. Because it’s not about the numbers. The best way to understand this is to use a sponge as an example. It’s much clear and you can combine it with the Mollier diagram. Use this link to download the coloured Mollier diagram (pdf).
My previous blog described what the pH should do during the composting process. This blog examines the role of the raw materials, such as ammonium sulphate, gypsum and water.
Chicken manure is an important raw material in mushroom compost and for the composter as it is the biggest source of nitrogen. It is therefore vital to keep the quality as consistent and as high as possible. However, the quality of chicken manure is unimportant for the farmer, for him it is a waste product. So make sure you always pay attention to the following points yourself.
Quality
Achieve the best quality with: - a nitrogen content (N) of 3.5 to 4%. The higher, the better; - a moisture content between 20 and 50%. The majority of composters work with dry chicken manure. The most suitable type is manure from broilers. This contains a higher percentage of actual manure compared to the rest of the constituents such as sawdust.
Regular supplier
One of the main aims of composting is to create homogenous compost: ensuring that you always supply growers with the same quality of spawnable or incubated compost. This process starts with selecting your suppliers, including the ones who provide you with chicken manure. Always work with the same chicken farmer, who keeps his birds in the same way. If you do not have a regular supplier, then you will have to compensate for the differences in the chicken manure.
Analysis is essential
Even if you do use a regular supplier, analysing the nitrogen and moisture content in the manure remains essential, even though the results of the analysis are usually the same readings. If the birds are sent to slaughter earlier or later than usual, there will be a direct influence on the nitrogen content. You won't see it visibly in the manure, but it will appear in the analysis. Using the wrong recipe to blend the compost has immediate and far-reaching consequences for your mushroom production. You won't be the first person to have two weeks of bad production….
Distribute well
Distributing the chicken manure over straw can only be done well once. The blending done afterwards will not compensate for any bad initial mixing. Every single blade of straw must come into contact with the manure. You must avoid any large lumps of chicken manure ending up in the compost.
Floor humidity
If you want to maintain a natural climate in the growing room during the recovery period until about five days after ventilation you should water the floor and walls of the growing room. Do this at intervals of between one and six hours. You will notice the result as a shock effect in the graph displaying the RH and growing room temperature. I will explain what is actually happening and how to avoid a shock effect.
The effects of floor humidity
If you stand in the growing room while the watering system is wetting the floors and walls you will see several things happening. The watering system contains nozzles which moisten the floors and walls with water droplets and it also creates tiny, airborne droplets of water. If you shine a torch you will see the little water droplets floating in the air. Eventually the droplets fall onto the beds and the sensors of the climate computer. This has two disadvantages:
1. Climate disruption
The water droplets which fall on the sensors are cold. They disrupt the climate, which causes a response from the computer. The effect is minimal but your aim is to keep the climate as constant as possible. This uses the least energy.
2. Abnormalities
The water droplets fall on the beds where the mycelium is recovering. These water droplets disrupt pinning, resulting in cluster-shaped abnormalities which develop before the first flush.
How can you prevent this?
Make sure that there is sufficient water pressure (see photo) while the floors and walls are being wetted. In this way you prevent the droplets from floating in the air. In addition, make sure that the whole floor is wet. This approach means that the floors dry out less quickly, ensuring that the climate in the growing room is more uniform and favourable for growth.
Mark den Ouden
Next courses:
Live training Mushroom Signals Essentials: 12 – 16 October 2020
The e-learning course offers the theorical knowledge of the Mushroom Signals book that is necessary for the live training sessions. During live training, all participants have the same basic knowledge, so there is plenty of time to deal with individual questions. This is not only valuable for the participant but sharing knowledge between the trainer and the other participants makes the theory more relevant. The everyday practice at the composting facility and the mushroom farm of the participants will also be discussed.
Other courses in 2020: 30 November – 4 December 2020.
Always available:
E-course Mushroom Signals Essentials
More info about the course see www.mushroomoffice.com
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