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.

For optimal climate control, accurate and reliable measurements are of course very important and maintenance to the CO2 box should be standard on every farm.

First thing would be to check the tubes and the magnetic valves for leaks. If valves are leaking they need to be replaced immediately as they will cause mixed air in the tubes.

All the tubes can get condense inside and block the air flow, also causing mixed air going into the CO2 sensor and sending the wrong value to the climate control computer. You can avoid this by blowing the tubes out regularly with an air compressor to avoid condense to gather inside them. Especially when tubes are not placed correctly and have no filter at the end of the tube this will happen easy.

A good practice on every farm would be to check the reference measument value on your CO2 system daily. That value is the CO2 measured in your outside conditions which is either outside, in the central duct or wherever the outside measurements sensors and CO2 tube are placed. The ppm value depends on where it is placed but should be consistent and seeing inconsistent value there can be a first indication that there is something wrong with your CO2 meter and some maintenance is needed. A good portable, calibrated CO2 meter can be a great help and indicator. You can detect problems before any misreading’s will cause more damage than necessary.

When all the tubes are clean and no leaks are detected the CO2 meter needs to be calibrated using a zero cartridge for the low values and CO2 calibrated gas for the higher values. Ask your supplier for the exact instructions.

Erik de Groot
Global Agriculture Services
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A lot of farms are afraid that water directly on mushrooms will damage the quality but I disagree with that. Of course it depends on the amounts of water you use and the moment of watering, those details are very important but if managed well the water on the mushrooms will give them a smooth cap and some extra weight. What we need to keep in mind is that the moment of watering is very important. Wait for watering on the 1st flush until you see compost activity. If there is no rise in compost temperature wait with water until there is. Normally you see the activity starting on the first picking day when you pick about 0.5 to 1 kg/m2. I always like to water on that first picking day, where the compost just starts to get activity, and let the mushrooms dry naturally, with no force of the fan but with fresh air. What happens is that when you run higher fan speeds after the watering, the fresh air damper will close. You can put a drying program where you lower the CO2 a bit but still the higher fan speed will not increase the amount of fresh air that is needed to dry the mushrooms.

Instead dry the mushrooms naturally and without too much help from the fan speed. Speeding up the fan a lot is not sufficient and is actually working the other way around. When the room is watered the RH is high so the climate system will automatically start drying the room. Leave the fan speed the same so some extra fresh air will come in to do the drying process. Make sure to remove all the access water from the floor directly after watering, if not the process will dry the floor first and the mushrooms will stay wet longer. Make sure you watch your outside conditions to guide this process, with very high humilities you have to use a drying program or consider not too water.

If you look at this in a glance one might say: the filling has not that much to do with picking. But it is more relevant than many people think. Before the start of picking a first flush, the picking manager makes a plan. When is the room starting? Do I have to pick clusters or pre-runners? How many pickers do I need in this room during lets say 5 days of picking? And an important one, what is the activity of the room? This I need to interact on the growing from day 2 of picking. And this is where the filling of the room comes into the story.

Before the start of picking the picking manager and the grower have a talk about this room. This should start from the moment pins grow out, so about 4 days before the start of picking that room. The picking manager has knowledge about the expected sales that week, the desired size of the mushrooms and the number of pickers available. The grower has knowledge of the room regarding the activity of the compost, the strain and the number of pins developing. An even room is easy to evaluate but if the filling was uneven or two different types of compost were used, than the story gets a bit more difficult. The growing room will develop uneven and one side might start earlier. One side might give more mushrooms and this means that the picking is not the same on all shelves. And with the tendency to build bigger rooms, more trucks of compost are filled in a room. And every truckload of compost can be a bit different. Sometimes in structure, sometimes in moisture content and even in quantity. And every time the operator of the combine filling machine has the desire to change the settings on the machine. Often his order is to get the compost filled. All shelves full and no compost returning to the compost yard or no compost dumped. But by changing the settings the temperature development of the compost will change too. 2 cm deeper fill can result in a difference of a day for the flush to start. It will also have an effect on the number of mushrooms growing out. And during the flush one side will grow faster than the other.

So the general instruction at filling should be not to make any changes. Better a bit of compost left over or a part of the shelves not being filled. An even better way is to fill out of two trucks in one go with a cross conveyor. That way the compost out of two trucks is mixed and differences are ruled out. Another method is to do a mixed fill of the truck at the compost yard. So fill a layer, fill another layer in another truck and then let the trucks circulate. Of course the best possible way is to do the mixed filling of the truck, together with the combined unloading at filling. The growing will be a lot easier then. The grower has a better chance to produce the number of mushrooms required and the picking can be a lot more accurate.