Drainage slits

The positioning of the drainage slits in combination with the right irrigation dose size influences directly the distribution of water and EC in the slab to produce the minimum variation of water content and EC laterally and vertically in the slab.

This is a job that has to be done only once but will influence the slab for the rest of the season, so it is very important that it is done correctly.

Additional drainage slits should never be made in the slab at a later date as they will change the drainage pattern in the slab which may be detrimental to the roots in some areas of the slab.

Ideally there should be the same number of drippers in every cube with no extra drippers put directly into the slab.

• Make drainage slits at both ends of the slabs at the lowest points.
• Make additional drainage slits exactly between the cubes as shown. This creates the same “cone” or drainage pattern for every dripper reducing the standard deviation of EC and more efficient flushing and water efficiency.
• This can also be done on both sides of the slab on hanging gutters to make sure that all the slabs drain evenly when the gutters are not quite level.
• Make sure that all the drainage slits are right to the bottom of the slab and are wide enough to prevent the roots slowing down the drain water (3 to 4 cm).
• Drain the slabs 24 hours before planting.
• Do not make additional drainage slits during the crop as this will change the drainage pattern in the slab and can cause root death.
• Never make a drainage slit under a dripper as this can give “false drain”.
• Make sure the job is done correctly as it has to last the whole crop so staff training and monitoring is critical.
• Please note that this way of making the drainage slits does not suit all slabs but is recommended to get the best out of Cultilene slabs.

Please contact us if you have any further questions about drainage slits.