Phase 3: Steering the crop based on water content during the final propagation phase.

Now the plants are firmly rooted in the blocks and spaced at the final planting density, the last propagation phase begins at the propagators. This phase differs for each batch of plants, type of crop and the customer’s requirements. The route to producing a quality end product for the customer is determined by the growing strategy and initial block selection. During this phase, the irrigation strategy is essential to ensuring the desired end product.

During the final propagation phase of the plants, the finish line approaches: the agreed delivery date of the plants. This is why different factors are involved compared to earlier growing phases:

• The desired plant type (age)
• The growing strategy of the propagator (temperature, lighting, screen etc.)
• The irrigation strategy (number of irrigation cycles, EC) applied to steer the plant

The plants are easy to steer during the period between planting and delivery. LED lighting plays an increasingly significant role in this process. But which light recipe is selected? Is there sufficient heat input if Son-T use is reduced? Which section/plant temperature is applied and maintained? The combination of these factors has a huge effect on the plant model, quality and the choice of irrigation strategy.

Continue to monitor block drainage using scales or a water content sensor. The irrigation strategy is also crucial to creating the correct plant model.

To steer plants generatively, the blocks must be able to drain sufficiently and have a large resaturation capacity, like the Plantop NG2.0 and PRO blocks from Grodan. Effective water distribution inside these blocks ensures good root distribution throughout the entire block, as opposed to predominant root growth at the base. This offers the advantage that growth is unimpeded and leads to less root damage when the plants are removed.

There are two grooves at the base of the Plantop blocks. Root tips protrude from the block in these grooves. This ensures that the root tips - that are ready to grow into the slab at the grower - remain undamaged when the plants are lifted for delivery. The fibrous layer on top of the Plantop block offers another advantage. The upper few millimetres of the block remain drier, reducing algae growth and the number of flooded pots during production at the grower’s premises.

Root growth will rapidly increase thanks to the effects of the irrigation strategy used during the generative steering of the plants. Due to effective resaturation and optimised water distribution throughout the block, plant growth is not disturbed and the entire volume of the block is used by the roots.

This table shows a number of terms and associated figures: