Greenhouse Production Systems
Substrate Culture Systems
Capillary Mat System
In a capillary mat system, the containers are set on a porous fabric mat from 0.1875 to 0.5 inches (5–13mm) thick that is in contact with the bottom of the container (Figure 15.6). Their principal use was to provide uniform watering on greenhouses benches. Water is inserted inside the mat through multiple pressure-compensating drip tubes running the length of the mat. This allows water to move vertically from the mat into pots through the drainage holes once plants are placed on the mat and capillary action is established.
Advantages and Disadvantages
One advantage of capillary mats is that plants of different sizes and water requirements can be placed on the same mat without under- or over-watering individual containers. Empty areas of the mat would not be subject to evaporative loss and can be restocked when practical. Using capillary mats should result in using much less water, and this watering method can increase crop uniformity and reduce risks of foliar disease. Bottom watering has been known to create stronger root systems and to prevent foliage damage. Additionally, the total containment can help to decrease pest problems as there should be less standing water around plants, and greenhouse films can stay drier.
Containers
With a capillary mat system, pots with flat bottoms are set onto a capillary mat. Containers must be saturated before being placed on capillary mat systems to ensure effective water uptake. The capillary mats must stay continuously saturated and in good contact with the bottoms of pots so that capillary action will draw water from the mats into the potting media. If the containers are disturbed in some way and the capillary action is destroyed, the pots must be re-watered from the top to reestablish the capillary action.
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