In the second part of this article (first part can be found here), the purpose of the picking technique is focused on using the S-curve. The technique is based on the ideal moment to harvest the single mushroom. Harvesting several times a day could increase production by 10% with the same retail quality percentage. To achieve this, the grower will have to harvest 25% of the mushrooms hours later. Yet another percentage of the mushrooms will have to wait until the next day (even though the picker wants to pick these first). An average of 10% extra production in three flushes can be achieved this way. This means an extra yield of 2-3 kg/m² (1-2 lb/sf) can easily be obtained, without concessions to quality.

Today, picking is often an unchanging task! The same number of pickers starts in the morning and harvest in a daily, unchanging routine. Only at the end of the day, when the other rooms are finished, do pickers in the difficult rooms get the help of a more people picking in the same room. As well as the organisational aspects, it's difficult to create the same amount of pins.

When the flush is underpinned with just ‘giants’, the same number of pickers normally harvests the flush. This first flush will end far below its production potential, because the pickers harvest too much: they can quickly pick good size mushrooms making 80 pounds an hour.

In this situation just a few pickers should harvest what is absolutely necessary, and if possible only once in the late afternoon. This type of break often shows no activity peak and produces equally throughout the first flush. Only a few pickers are needed to harvest those rooms each day.

When the flush is heavily overpinned there will be such an abundance of mushrooms, it will be almost impossible to get the fingers in between them. This type of flush can be staggered to create space between the mushrooms for air circulation. In the outgrowth the ppm concentration underneath the mushrooms is so high that it cannot be measured anymore, and this will push the whole flush to ripen quickly.

Organising harvesting

A higher picking frequency (maybe 6 times a day, or more) will create space and extra nutrients for the remaining mushrooms. Maintain the flush by creating better air-circulation around the mushrooms.

The mushroom grows according to the S-curve, doubling in weight and size in 24 hours. This means; 25% in weight in 6 hours, or 10% in 2.5 hours.

The (old) standard method of picking is to pick three times a day in the first flush: Firstly the giants are picked, followed by the medium size and thirdly the medium/small.

Another approach is to harvest as follows: The first step is to harvest the ripe Giants that really need to be picked, leaving all other Giants until the afternoon or even the next day. The next step is thinning; only trays with numerous (groups of) mushrooms are harvested where needed. After thinning the pickers have to take the groups of larger sized medium followed by a round of standard groups of medium. The next step is to pick Giants again, leaving those Giants with enough space to stay good until the next day. Finally the harvesters turn their attention to the groups of small, ripe mushrooms, and to clearing the bed (fallen mushrooms, stems etc).

How to create space at overpinning

If the flush is overpinned it is mainly picked when the flush ripens when suddenly all the small mushrooms with long stems need to be picked. In retrospect: the flush is hardly touched the first day; medium grades are picked on the second day and the bulk is harvested in the small size, which are left to gain weight. On the third day the flush is picked off. Actual number of harvesting days is two! A lot of weight ends up wasted because the long stems are cut off.

A better way to harvest is to create space on the first day of harvesting. The room should be picked (thinned out) twice and all the medium sized mushrooms left in place to stagger the flush. On the second day the room must be harvested 3-4 times by thinning the groups of mushrooms and leaving the medium size where possible to stagger the flush further. On the third day the flush is fairly spread out and could be harvested 6-8 times, with the pickers always focusing on the concentration areas, to create small Giants!  By creating a better spread the flush can continue into a fourth picking day. On day 4 pick over the room 3 times, taking care to leave all the small mushrooms. This will be still good the next day. The imminent second flush will now be staggered. The harvest manager and grower can now discuss how to bring in the 2nd break. On the fifth day the between flushes will be harvested 1-2 times. The result will be better quality and colour, a longer first flush, and a longer shelf life. And contrary to expectation the weight of the heavy pinned flush can reached 20 kg/m² with over 85% of retail quality.

Considerations

Harvest managers need to realize their current situation and have a clear idea of where they are aiming for. He must be aware of what kind of mushrooms are growing “today”, how many lb/sf (kg/m²) is today's expected yield and the right measures to be taken in order to get there.

Aspects to be considered are: compost activity, the time of the year and the sales price of mushrooms. In addition, the flush may be pinned on the surface, or developed too deeply into the casing soil, the filling weight of the compost can different (shortage, or extra compost available) while the staggering may possibly be good but the flush is simply two days too early, or a day too late. Other difficulties include the casing moisture content, a varying structure or inadequate homogeneity of cac-cing.

All these factors influence the way of picking. For example, if cac-cing is uneven with fewer mushrooms in the middle of the bed (tray) and more than average pinheads along the sides, then the sides need to be thinned and the middle of the bed left untouched when the harvest starts.

The essence of the picking technique

The above emphasises the contrast to the Dutch way of picking where the harvest manager estimates how many pickers are needed in which room: how many pounds are to be picked, the percentage of which size, and the picking speed. The hours are added up, and taking the skill of the individual pickers into account, a number of pickers are assigned to each room. And to the areas of the room requiring the most attention. Everything is evaluated again the next morning, and throughout the following day. The harvest manager guides picking (with the example of the overpinned room in mind, this may mean more pickers in the room because the picking speed is slower).

Even with selective picking, the harvest manager needs to evaluate if the “routine” of picking is still efficient. For example, the market demands change and picking practice can be adapted to create better profits.

The purpose of this technique is to use the S-curve: the 10% increase in growth by picking several times a day, or 25% by leaving mushrooms that can be picked hours later or 100% by simply leaving perfect mushrooms until the next day. Creating space between the mushrooms creates space to earn extra profits.