Propagation begins with sowing in plugs. Grodan Pro plugs are designed to offer greater handling possibilities with automated machinery. They are made of a stronger type of stone wool and with seed holes with an improved shape. They offer the advantages of better handling during the selection process , resulting in uniform batches of high-quality seedlings for selection or transplanting.
Hans van Herk
Hans van Herk, Grodan specialist for propagation, discussed the properties of the Next Generation of capillary stone wool blocks, which are most suitable for propagating compact, healthy plants with plenty of roots in the block. The fact that the new blocks can drain well and can subsequently be re-saturated makes it possible to steer the plants’ growth by promoting generative or vegetative development. There are two types of Pro blocks. The Pro block intended for tomato, cucumber and aubergine plants is very firm and can be effectively influenced to promote (generative) growth. Its water content can decrease to 40%, while its EC can increase to 8 or 9mS, in the case of tomato plants, between irrigation sessions. The Pro block intended for sweet pepper plants is also firm, but it promotes “easier growth”. as good vegetative initial development is important with sweet pepper plants, so it is important to be able to water them more frequently. Both types of blocks are suitable for automatic processing, for example using machines that automatically pick up and space the blocks.
SowingAd Kranendonk of Flier Systems explained the solutions for propagating young plants in stone wool plugs. Flier Systems has developed separate product lines for sowing, planting and grading plants in stone wool. Key concerns in developing those product lines were precision sowing, the possibility of switching seed drums quickly, uniform irrigation during initial saturation and uniform distribution of vermiculite following sowing. As the processes are computer controlled the settings can be saved. This makes it very easy for operators during the change over of crop types.
GradingThe advantage of automated grading is that it enables plant producers to offer their customers a uniform end product of a better quality.
At Flier Systems the plants are automatically or manually placed on a conveyor belt that transports the trays to a robot. The robot then lifts the plants from the trays and transfers them to tailor-made transport cups. The plants then pass through a camera system that evaluates various parameters such as plant height, leaf area, stem thickness and colour. After this evaluation the plants are categorised into 3 different grades.
Hans Preesman of the Italian company Techmek demonstrated the advantages of his company’s I-Tech: a stable system entailing low maintenance costs. The system is based on two industrial robots and patented cogged conveyor belts with loose cups that are magnetically held in place. The plants are lifted from the trays, transferred to the cups on the conveyor belt, graded with the aid of two cameras and subsequently individually picked up and spaced further apart in new trays.
In the grading system of the ISO Group the plants are lifted straight from the sowing trays, assessed by a camera system and then placed in trays according to their grade. This is a compact, low maintenance system that is very efficient, providing there is sufficient contrast between the plants and the propagating medium, and the plants project at most 50 mm above the tray.
Grafting robotGrafting is a labour-intensive operation that must be done with great precision. Andreas Hofland of the ISO Group showed the audience a film of his company’s (semi-)automatic grafting system explaining how a single robot lifts up both the rootstock and the plant to be grafted, cuts them (perpendicularly or at an angle of 45°) and then clips them together. There are a fully automatic and a semi-automatic versions available. Of course the decision to invest in a grafting machine will be based on a number of factors, not least labour cost and quantity of grafting. However grafting of field grown crops is also becoming more popular in the never ending battle against soil borne diseases. In this respect what would seem to be a potentially interesting application is a machine to graft melon plants. Large numbers of melon plants are grafted all over the world, but the fact that the rootstock must be grafted to the plant along with a leaf could prove a challenge. Grafting machines of the ISO Group are currently in operation at six companies, in the Netherlands and Japan.
Picking up and transferring the plantsHans Swinkels of Ideaal Machinebouw en Constructie demonstrated automatic systems for picking up plants and transferring from the transplanting or blocking lines to the greenhouse. Thanks to a scissor system the blocks can be lifted and spaced during growth as required.
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Harriette Rademakers - Grodan