Apr 21, 2021

A good start for a blog just around Spring time. But the meaning is different.
It just means: Keep It Super Simple.

On many farms I assist in the picking instruction and the complaint most often heard is that the pickers do not listen. This is not entirely true. They do listen but they do not store it. They are thinking of many things and the mushrooms is not one of them.
So it is up to the supervisor or trainer to make sure the information gets through. She (or he) first has to get to know the picker. Then decide what method can be used. The best supervisor changes her role according to the person she talks to. She can be a teacher, a mother or your worst nightmare if needed. Depending on the person and the situation. But she knows what is going on in the mind of the picker. For the picker money and nice work is important. But they have no notice of how mushrooms grow and how to pick more kilo’s per m². They want to pick fast because most of the time their bonus is related to pick rate. But often they do not realise that it is not about working fast but about working smart. And a good instruction can help with that.

How to do a thing like that in a practical situation?
Let’s say stems need to be longer.
First explain to a picker that a longer stem can give them up to 10% higher pick rate without working faster. Just look at the stem and do not cut it of completely. Then translate the 10% extra to a 10% higher salary. The farm by the way has a 10% higher production. If they understand that, the power is in repeating. Not just in spoken word but also in visual signs. Make a project of this. For one complete week only instruct on stem length in the rooms and do this on individual level. So no shouting through the room but address every picker personally. The next part is a good photo which is shown for a week on all possible places. In the canteen, on the tables, in the corridor and even in the toilets. Just for a week because after a week they do not see the photo anymore. The next week another subject is chosen.
And for the supervisor: the power is in repeating. Tell them once, twice and keep going on. If the pickers see you, they immediately think of stem length. This way it is imprinted in their way of thinking and it is much easier to have success.

So Keep It Super Simple and act like a parrot.


If a consultant is visiting a farm there are always many things to discuss in detail.

Shall we give more or less water and are we able to water over the mushrooms?

Do we need a slower or faster fructification?

Is the amount of pins sufficient or do we need more and how do we then get a decent stagger?

Even discussions about compost although many growers do not really know the details. But they know about structure, moisture and smell. Because this is what they discuss at filling.

The same about casing soil. Is it heavy this time or just fine? Wet or dry?

But talking about supplement one finds out that most of the growers have absolutely no idea how it works, what it really is and the choices they can make. Generally the price is the main buying point.

And this is strange to me. Because compost and casing are always changing during the year. This is mainly due to the seasonal effect on the raw materials. Straw is maturing in the storage, chicken manure will change in nitrogen level and peat is changing moisture depending on the season of the year. Manufacturing companies will react to that but smaller changes are inevitable.

To keep production at the same level or to enhance it, the supplement however can be changed to your liking. Most of the growers only know that there is a slow or normal release product. But it is possible to customise the supplement to the situation of that moment. Not just slow or fast but even pinpointed to a certain phase of the growing. To give an example: one of the farms I work on now wanted more activity in second flushes and a longer shelflife. In cooperation with the compost supplier and the supplement supplier they have now “composed” a supplement that can do that. Be aware though that it also needs adapting of the growing. You are putting more proteins into the compost so the activity changes too. This means that also the watering and the picking have to change.

But this way many combinations are possible.

There are different raw materials to mix and several processes to make the release time fitting your schedule.

A few remarks though have to be made.

It only works well in cooperation with the compost supplier. The ingredients of the supplement have to be an addition to the nutrients in the compost. So it has to fit the analyses of the compost.

The best way to use it if it can be mixed in at the compost yard. And this is only profitable with bigger quantities of compost. Mixing it in at filling is not as efficient as on the compost yard.

Do not just look at protein levels. Because some proteins are not available to the mushrooms and will still be in the compost at the moment of emptying the room.

So look at effective protein. This often is a matter of price. Good proteins come with a price.

And remember: good supplement makes good compost better. But good supplement makes bad compost worse.


One of the most seen disease in mushroom farms is the dry bubble, caused by the fungus Verticillium fungicola. Its easy to get an infection in the farm and because the disease is very infectious it can spread quickly through the whole farm. Especially in big farms, where many pickers are working, the dry bubble will spread very fast and can cause a lot of damage and be that bad that 3rd breaks may be lost. Pickers should be getting all the information about the dry bubbles so they can detect the infection in an early stage.

2021 Blog week 7 Article dry bubble

A dry bubble in a 2nd break.

Dry bubble is generally caused by spores around the farms in windy, dusty conditions. On filling days when its windy outside with dust in the air its very well possible to get the dry bubbles into the farm. When they are spotted before he 1st break, the infection came in at filling. Once inside it’s a matter of time before the spores are everywhere if not handled well. Hygiene on the farm should be checked and especially have a good look at all the materials that are used for your mushroom waste like stem bins. Spores of bubbles will be present there if not cleaned well and can be spread if materials are getting moved between rooms. Also pickers are a concern for spreading the infection. Spores are sticky so everything that gets touched after touching a bubble can get infected, be aware!!!, it can go rapidly.

Removing the bubbles is off course also very important. When the pickers don’t recognize a bubble and are picking mushrooms while touching dry bubbles it will be always be hard to control the infection rate. Educate them well and spread around as much information as you have to inform pickers about the diastase and the big risk it has on the results of the farm. Let them, or the picking lead, report the infection so a special crew can handle it the right way.

When the pickers recognize the bubbles, the next step is removing the infection as soon as possible. Makes sure when you remove the bubble you don’t spread the spores what will results in more bubbles within 4 to 5 days. Use a wet tissue to cover infected spots too avoid the spread and remove all the spot including the casing soil, using a plastic bag. Close the bag immediately after you have the bubble and surrounded casing soil inside and remove the bag from the farm as soon as possible. You can also leave it in the affected room and remove it after cook-out. After removing it use salt or ammonia to cover the infected area and inspect the area every day to see if the infection is spreading.

It all comes down to a good hygiene, organization and education. Infection can occur suddenly but if threated the right way can also be stopped rapidly. Organize it well so that infections get removed before rooms get picked or watered, those are moments when spores will spread. If everybody recognizes the disease and knows what to do and handles right, bigger problems can be avoided. Hygiene is key, not only for dry bubbles, and should never be underestimated.

Erik de Groot
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Chicken manure

Jan 26, 2021

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.

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.

The last month several growers had problems with a too heavy casing soil. It is normal for this time of the year for casing soil to be heavier because of rainfall on the peat fields. It takes a few weeks for the casing companies to sort this out and in the mean time the grower has to deal with this. A normal situation for this period. Complaining is not the way to deal with this but inter acting is possible.

The first thing to do is to recognize that the casing ís heavy. This can only be observed if good attention is given to the filling of the room. Always talk to the truck driver about compost and casing and you already know a lot. They know exactly what material they carry. If they say it is a heavy load and if water is coming out the first thing to do is to adjust the filling machine. Heavy casing soil packs more so it has to be opened up. The caccing spinner on the combine filling machine plays a big role in this. It has to pick up the compost and mix it well into the casing. Cac a bit more than normal if casing soil is heavy. The next step is to make the mixing spinner turn a bit slower. Too intensive mixing will destroy the structure and cause big problems in outgrow of the pins later on. The pressing roll should be adjusted that way that it does not close the holes in the casing. If you look at the roller from the side of the shelf, a little bit of light should be visible between roller and casing.

Then be careful with water on the first day. Make sure the caccing material starts growing. This can be seen by the attachment of the compost to the casing. Do not wait however till you really see the mycelium. Because then the time for watering can be too short. And mycelium will overgrow the casing. The normal amount of water can be given minus a few litres. (the water on day one). It is a good thing if watering gifts can be split into small doses. 1 litre at a time with intervals of at least 1 hour. Only on the first watering day (probably day 2 after filling) bigger gifts are possible.

The next thing that might happen is that the mycelium has difficulties growing to the surface. Remember, a heavy casing soil needs help to release water and CO2 so always make sure that fresh air is given to the room. A minimum of 5% fresh air most of the times helps a lot. If the mycelium has reached the surface generally the fructification is normal. The only difference is from day 7 to day 10 of the fructification. From that day 7, the pins might stagger in outgrow. At that moment again fresh air is needed to keep the evaporation going. A minimum of 5% might not be enough anymore. If you see pins but they do not grow out you have a few possibilities.
A drop of water as a shock. This means 0,5 litre of water and mild drying with heating and fresh air. Fan can be set up to 5% higher in speed.

Or you can drop the CO2 to about 1000 ppm for a day. But make sure that RH stays over 88% in this case.Overall the growing later on will be on a bit lower CO2 than normal to keep evaporation going. Watering as normal. The biggest mistake made is to keep rooms like this too dry. Be aware that the room might develop less pins than normal. Let them grow out and pay special attention to the picking. This way these rooms do not have to be any worse. On the contrary, often they are better (in a financial way) than normal.

Recipe for a new year, keep the buttons up!

March 2020. Everything looks good and I have got my pocket full of tickets. Flights all over Europe and many visits to make.
But a week later everything looked different and still does.
Corona is sweeping over the world and people do not know what to do. Traveling has come to a stand still and most of the consulting is done over the phone.
But does it have good sides too?
Fortunately, so. It is a proven fact that corona has less chance to infect you if you are in a good state of mind in a fit body. Or at least the symptoms are less severe.
For most people in this modern world that is a bit of a problem. A great deal of mankind has a problem with being too heavy and is suffering from obesitas.
And just this morning I heard that loosing 5% of bodyweight (if you are too heavy) means already a big boost to your immune system.
So, go outside, exercise and eat good food.
And it is a proven fact that mushrooms exactly fit into that diet.
Mushrooms are low in fat, rich in vitamins (vitamin B and D even more in brown Agaricus)and they are loaded with complex carbo hydrates.
A good reason to eat mushrooms and use it as advertising. Countries as Spain and Hungary are already doing this on a large scale and I am sure many other countries do the same.
But it can be a lot more. If I just look at Holland, the consumption is still very low and that can only be changed if we as growers tell about the health aspects of our product.
And of course, the taste is good.
To give an example I would like to share a recipe with you.

Mushroom Gougère. (serves 6)
Melt 75 grams of butter in a pot.
Add 2,25 dl of water and bring to the boil.
Add 100 grams of wholemeal flower at once and mix well.
Mix till the dough lets go of the side of the pot.
Let cool a bit and then mix in 3 eggs, one by one.
If the dough is smooth, mix in 75 grams of grated cheddar cheese.
Put the dough into an oven dish. Leave the middle open. Put the dough only on the outside rim.

Then put some oil in a skillet and fry 2 chopped onions.
Add 2 cloves of chopped garlic and I kilo of sliced mushrooms.
Add one spoon of wholemeal flower and 2 dl of vegetable broth.
Bring to the boil for 3 minutes till the mix thickens.
Then add 200 grams of chopped walnuts and 2 spoons of chopped parsley.
Ad pepper and salt to your liking.
Put this mix in the middle of the dough in the oven dish
Cook this in the oven at 200° for 40 to 45 minutes.

If you share this recipe with your clients you might sell a lot more mushrooms and create a healthy and good world.

Best wishes for 2021 and stay healthy.

Henk van Gerwen

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