Field Manual

CWI

How the Controlled Watering System works

The water from the reservoir flows into the soil through the tiny holes at the bottom of the CWI. The water wicks its way up through the soil until it reaches the tip of the moisture sensor. The tip absorbs water, preventing air from passing into the tube.

A vacuum develops above the reservoir, preventing saturation in the soil. As the soil starts to dry, the sensor dries and opens up. The vacuum is broken, allowing water to flow back into the container, until the soil becomes moist again.

The process is a cycle, interrupted only by the removal of the stopper, and the filling of the reservoir.

Biobarrier

Planter Technology recommends the use of Biobarrier fabric (sold separately) to prevent the growth of roots into the water reservoir. One Biobarrier square is placed (either side up) into each "cup" at the base of the CWI. Square does not need to be trimmed to fit. Fold excess fabric up sides of cup. Observe precautions on packages of Biobarrier.

Planting

The CWI functions best when planted with the same size plant (i.e. 10" plant into CWI-1000). Firmly pack moist potting soil into "cup" (on top of Biobarrier square), and across bottom of insert. Remove plant from nursery pot, place into CWI. Crown of rootball should be 1/2" below level of fill hole. Pack plant firmly into CWI, making sure to add soil around sides to fill gaps and voids.

Sensor Placement

Check to make sure white tip is at end of sensor tube. Dip tip into water for 15 seconds to activate. Make sensor hole with stake or probe at a 45° angle into soil. Remove stake or probe, insert sensor into hole. Sensor tip must be 1/3 to 1/2-way down in the soil in the CWI. Tube showing above soil should not loop, kink or bend. Make sure to backfill soil around sensor, packing firmly.

Filling and Maintenance

Prior to filling reservoir, check to insure that soil is moist and well packed, and that sensor is placed correctly. Remove stopper, fill with clean water until reservoir is overflowing. Use funnel or water machine for best results. Check water level no more frequently than necessary (typically every two weeks) with straw, tube, stake, etc. Refill before reservoir goes empty. Moisten stopper and replace, pushing firmly with a slight twist. Fertilize with Planter Technology HM-10, or other water-soluble fertilizer. For other fertilizers, use 1/4 strength recommended by manufacturer.

Troubleshooting

The properly functioning CWI will normally have dry topsoil, and after two weeks the water level in the reservoir will have dropped. The soil 1"-2" below the surface will be moist, but not wet.

Signs of Overwatering (the more common problem): Topsoil is wet or damp to the touch. Removing stopper to check water level more often than necessary will lead to overwatering. To correct, repack soil into CWI. Check that stopper is securely in the fill hole. Make sure that the sensor is solidly in soil. Allow soil to dry out until the topsoil is dry to the touch before refilling reservoir.

Signs of Underwatering (a less common occurence): Reservoir level remains unchanged between fillings. Look for signs of water stress, and test moisture level at least 2" below topsoil for moisture (the plant may not have needed water). If dry, top water slightly to moisten soil mass. Do not overwater.

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