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Akkie's Tuin (29)
High, higher, too high?
After the last water during the incubation in the casing soil, the grower wants the mycelium to grow onto the surface. To ensure a good recovery of the mycelium in this period the right settings for the room climate are essential.
An RH at a minimum of 95%. A very slow air speed, if possible zero and an adequate room temperature. That room temperature should be as close to the optimum for vegetative growth as possible. That optimum temperature is 25° C to 26° C.
This means often a room temperature of around 21° as a minimum. Then the mycelium has the right conditions to grow onto the surface.
The next question is: how high do I let it grow ?
Higher means better control of the number of primordia, so no surprises about the number of mushrooms growing out. Higher also means easier picking so a higher pick rate. Another positive experience is that clustering is easier avoided.
But the big dis-advantage of having the mycelium higher on the surface is that the climate conditions have to be perfect. The influence of the climate onto the mycelium and the primordia is bigger. So one moment of for instance too low RH means that you will lose primordia. Deeper mycelium is also easier to stagger the mushrooms so that is an advantage too. Another point is the fact if the grower can stop the mycelium when it grows too high. Overlay as that is called makes the outgrow of primordia more difficult. They come from underneath the blanket of mycelium.
So what determines the choice?
Both ways have their pro’s and con’s.
But for me the crucial point to choose a way is the technical capacity of the farm and the experience of the grower. If you are able to stop the mycelium at all times, still create the stagger and have perfect control of the environmental conditions, grow white.
If you are not sure of all this, grow deeper into the surface of the casing soil. So grow blacker.
Generally blacker is safer.
Picking and calibration
Generally picking is considered by many as a low education job. But on the other hand, we rely on our picking force to deliver a good quality mushroom, meeting the customer demands. No bruised mushrooms, no nail or knife damage, right stem length, straight cut stem, no weak mushrooms in the punnet and for all, the right size. And that is where many things go wrong. It is fairly easy to learn the pickers the right way of picking. Twist and do not pull. Do not take to many mushrooms in one hand so they do not get damaged and put them caps up into the punnet. But getting the calibration right is a constant struggle. Pickers tend to have the habit to pick too small and this will cost you money. They simply pick the mushrooms that were meant to be picked tomorrow. An extra thing to that is that pickers lose the bonus while working really hard.
For the right calibration there are many tools like fruit grading rings, grading cards and other different tools. But the easiest tool they have in their hands: the knife.
The knife most used in mushroom growing is the curved knife and the length of the blade is exactly 60 mm. The calibration most wanted on many farms is 55 to 60 mm. Generally, this size is picked first before thinning out. And this is just the size of mushroom that is as wide as the length of their knife. They just have to keep the knife just above the mushrooms to judge the size. This way the mushrooms can be calibrated before they are picked and they will not be damaged by any other form of grading tools. The rings only let mushrooms through which are small enough. The bigger mushrooms get stuck and will be damaged. But the mushrooms that go through easily are too small and that is the calibration the picker will harvest. By using the knife not only there will be no damage but it is also faster.
If a smaller calibration is harvested like a 40 mm mushroom, a line can be made on the blade with a marking pen. Especially new pickers will be very fast in learning this trick. By banning the calibration rings also, the hygiene on the farm is served. Because these rings are hard to clean and experience learns that they are always dirty and are taken from room to room.
Give it a try and your harvesting staff will be happy.
Europe is now at the time of the year summer will burst out. And every year the same growing problems occur at this time, getting worse and worse every year.
Summers seem to get hotter and it is time to adapt before real growing problems are there. There are a number of things growers can do but of course a good cooling system is a must. Well calculated, fitting the circumstances of your own country. But even the best cooling system will not cover everything. If we take the summer temperature last year in Holland at 42° nobody has a cooling system which will handle these extreme temperatures in our country.
If at the same moment also the relative humidity is high it is not only cooling but also the heating that counts. And that brings me to the first mistake many growers make. In summer switch of the heating system. Its hot enough outside, I do not need heating. Wrong!!!
De-humidification only works if the cooling can work in combination with a bit of heating. So, by switching of the heating the system can make the air dryer anymore. And you need dry air to cool a hot room. The easiest way to cool a growing room is to give water to the casing soil. The best way is to give many small quantities up to 2 litres. That can be evaporated again. Spread the watering over 24 hours. The dry air coming into the room will take care of the evaporation and will help cooling the growing room. Keep the casing soil wet but the floor as dry as possible. That is why I do not close the room completely if the outside is hot but dry. It is possible to use air which is much higher than the compost temperature as long as the incoming air is dryer than the air in the room.
In the mollier diagram one can calculate how much fresh air is necessary to absorb the evaporated water in the room. And for that cooling by evaporation you only need a few litres of water extra. No extravagant quantities as some growers tend to do. An extra help will be some mobile coolers on the farm. They can be placed into the room just before the heat surge is starting. The price of such a mobile cooler is a lot lower than the costs of losing a room.But in the end, judging a room is important. If compost is active and the C/N ration is relatively high one can expect activity. It is of outmost importance that cooling starts before the surge starts. Once a compost is going up it is hard or impossible to stop it.
If one wants to start a discussion with a grower (or with a consultant), start talking about watering.
How much, when and what watering method.
To make any sense though, you first have to define the period. There is watering on casing soil and watering over mushrooms and between flushes.
This blog is about watering on the casing soil during the incubation period. The water given in that period is to bring the casing soil up to the maximum moisture level and to keep the compost at the right moisture.
A good phase 3 compost at the moment of casing will be around 60% in moisture. For white strains that can be up to 3% higher, brown strains prefer 1 or 2% drier. It is not possible to bring the compost to a much higher moisture level by watering it after filling. It is possible to give water into the compost but that will be free water which has to disappear during the fructification period.
2 up to 4 litres of water can be given into the compost at filling or later but that should be the maximum. Even if it is necessary to cool the compost. This can better be done by giving water into the casing and let it evaporate with fresh air and circulation.
Casing soil itself can handle up to 7 litres per m² plus the water that was originally in the casing. To be sure, we talk about a casing containing white and black peat.
More than 7 litres will evaporate, go into the compost or down the drain.
Considering that the evaporation can be around 2 litres per m² per day, the loss with evaporation is about 10 litres. If you count the loss of dripping, the water staying in the compost and the evaporation you come to a figure of about 25 litres of water. In practical situations this means a total amount of water between 20 and 30 litres average. Depending on the farm and the time of the year. Growing drier often means a loss of production and growing a lot wetter means problems in growing, mainly in the outgrow of mushrooms.
Another thing to watch for is the watering method. Make sure that the pressure of the water onto the casing is not too high. Too many times I see a casing with a damaged surface which will give problems in the evaporation.
Every system has a different pressure and if you are not sure, ask the manufacturer. Regularly cleaning of the nozzles is something will help maintaining the right pressure and the right adjustment of the watering trees, looking at distance and height according to the casing level.
Keep watering but do not take it over the top!!
These three principles are the base of disease control on a mushroom farm. To my opinion there is no farm that has not a spot of disease somewhere.
But depending on what is done it will develop into a serious problem or it will stay a hidden time bomb.
If a problem is discovered it is of crucial importance that is recognised. To make sure that will happen training of people on the farm and especially pickers is needed. They are your eyes on the farm.
They need to know the most common diseases and especially in a young stage. Many places of dry bubble are not recognised and are only seen if the disease is in an almost incurable stadium. The small wart on a mushroom or grey spot is often missed.
The same goes for insects. Many growers do not know the difference between a phorid and a sciarid. Although the damage pattern is totally different, so Is the threshold where it really starts costing production. Also the cure is completely different.
Example: growers use diflubenzuron against phorids.
It is only active against sciarids.
If the disease is recognised then it should be isolated. It can be covered on the spot but the most important is to simply keep all doors closed. Check filters and door seals. If a room is infected, make sure the infection is contained in that one room and does not spread on the farm.
After the isolation the disease can be treated. If the spot is detected in an early stage one can do with just a sport treatment. If it is more the whole room should be taken on.
But too often the infection spreads and the whole farm must be treated. Generally room treatment for a full cycle with an overlap of two or three rooms to break the lifecycle of the disease.
So, just a test:
Look at the photo and spot the phorid. Or is it a sciarid?
A good stagger to meet targets
The targets for a mushroom farm are amongst others:
• Meet market requirements
• Good quality at the lowest possible harvesting costs
To meet the market requirements the farm needs about the same amount of mushrooms every day, seven days per week. Maybe a bit more on one day than the other depending on sales. This means generally picking seven days per week.
Imagine the third picking day of a first flush. In the morning the pickers are picking a beautiful mushroom.
Around noon the mushrooms are starting to lose colour and 3 hours later they start growing like mad. Stems are stretching and caps are getting soft.
It looks like we are not going to have any winter this season in Europe. On the contrary. It is very wet and humidity is very high.
This has its reflection on compost and casing.
If raw materials for compost are stored outside or under just a roof, they are evaporating less water and in the same time some materials get wet by the rain.
Keep an eye on the ball
At the end of a year or at the start of a new one it is always a good thing to look back and forward. Look at it as an evaluation and re-focussing of targets. It is also a good time to give yourself and your team a feedback.
Looking back to 2021 it was a year of great challenges. We had our normal variations in compost and casing soil quality. It still is impossible to predict the weather so we still will have to cope with changes in raw materials due to the weather. And reacting to that always comes too late.
Picking and calibration
Generally picking is considered by many as a low education job. But on the other hand, we rely on our picking force to deliver a good quality mushroom, meeting the customer demands. No bruised mushrooms, no nail or knife damage, right stem length, straight cut stem, no weak mushrooms in the punnet and for all, the right size. And that is where many things go wrong. It is fairly easy to learn the pickers the right way of picking. Twist and do not pull. Do not take to many mushrooms in one hand so they do not get damaged and put them caps up into the punnet. But getting the calibration right is a constant struggle. Pickers tend to have the habit to pick too small and this will cost you money. They simply pick the mushrooms that were meant to be picked tomorrow. An extra thing to that is that pickers lose the bonus while working really hard.
For the right calibration there are many tools like fruit grading rings, grading cards and other different tools. But the easiest tool they have in their hands: the knife.
The knife most used in mushroom growing is the curved knife and the length of the blade is exactly 60 mm. The calibration most wanted on many farms is 55 to 60 mm. Generally, this size is picked first before thinning out. And this is just the size of mushroom that is as wide as the length of their knife. They just have to keep the knife just above the mushrooms to judge the size. This way the mushrooms can be calibrated before they are picked and they will not be damaged by any other form of grading tools. The rings only let mushrooms through which are small enough. The bigger mushrooms get stuck and will be damaged. But the mushrooms that go through easily are too small and that is the calibration the picker will harvest. By using the knife not only there will be no damage but it is also faster.
If a smaller calibration is harvested like a 40 mm mushroom, a line can be made on the blade with a marking pen. Especially new pickers will be very fast in learning this trick. By banning the calibration rings also, the hygiene on the farm is served. Because these rings are hard to clean and experience learns that they are always dirty and are taken from room to room.
Give it a try and your harvesting staff will be happy.
