The evaporation of the plants controls the irrigation

With a drain tray or a start tray the plants decide when to be irrigated. The start tray and the drain tray are used to control the irrigation of cultures grown in rockwool or perlite, e.g. tomatoes, cucumbers, and mother plants.

Function of start tray

Rockwool slabs with plants are placed on the start tray. It is important that the plastic foil is removed from the bottom of the rockwool slab. If perlite is used, holes are cut in the bottom of the bags with perlite, so that the excess water can run off.

During the irrigation, part of the fertilizing water will remain in the rockwool, and part of it will seep into the reservoir of the tray. The reservoir of the tray is connected to a sensor. The Start Tray / Drain Tray sensor gives a signal for irrigation, when part of the water in the reservoir has been consumed by the plants placed on the start tray.

The quantity of water to be used, before a start signal is given, can be adjusted by lifting or sinking the sensor electrode. The electrode is connected to an irrigation device which starts the irrigation, when the electrode has given a start signal.

Function of drain tray

The drain tray works in the same way as the start tray, i.e. the rockwool slabs are to be placed on the tray. It is important that the plastic foil is removed from the bottom of the rookwool slab. The drainage performed during an irrigation is measured by a drain counter, which is connected to the tray. This is shown on the photo above.

Contrary to the start tray, the drain tray cannot trigger irrigation itself. The drain tray has to be connected to a computer with a program controlling the drainage.

The program for control of the water frequency dependant on the drainage uses the sun-integrator of LCC 1200 climate computer as a start condition for the irrigation device, for instance AMI irrigation-fertilizer computer.

Control of the desired drainage percentage is performed by adjusting the sun-integrator's quantity of light so that the pause between the irrigations is changed dependant on the deviation between actual and desired drainage percentage. The drainage percentage is to be adjusted in the program.

Water saving

Control of the drainage quantity saves water, and at the same time it is ensured that surplus of nutrient matters led in and root exudates are not accumulated in the slabs.

Readings give a broad view

The drain program contains a number of readings, e.g. drainage percentage, total drain per plant, and drain per plant since midnight. Besides, it has information regarding total quantity of water led in per plant, quantityofwaterled insince midnight, and total performed irrigation time per plant since midnight.

Further possibilities

Registration of irrigations can be performed by connecting a PC with the SuperLink program installed. With the PC program there are several possibilities to change the setpoints and collect the data. As far as the start tray is concerned, it is necessary that it is connected to an AMI1000 / 5000 irrigation-fertilizer computer.

New Improved Product

SuperTray

Technical Specifications

Required for drain program: drain tray with drain registration equipment and climate computer LCC 1200, version Super, with irrigation program.

Drain tray - maximum drainage rate: 300 ml/min.

Standard lengths of the start tray / drain tray are 200 cm and 240 cm, but special lengths can also be delivered on request.