Which Growing Mediums?

The growing media you choose to use with the IWS Dripper system comes down to personal preference. Good results can be achieved with many different medium’s, but the key features you should look for are:

  • Low-medium Water Holding Capacity (WHC)
  • High Air Filled Porosity (AFP)

Expanded Clay Pebbles

Clay pebbles while ideal for flood and drain aren’t really suitable for the IWS Dripper system as you would have to have a high feed frequency which on a run to waste system would waste too much nutrient solution.

Coco / Clay Pebble Mix

If using a coco / clay pebble mix, the percentage of coco should be  25-40% of the total volume of the growing media. Adding coco will allow more time between feeds which means fewer feed cycles per day.

Understanding the Feed Cycle

To get the best results from your IWS Dripper system you must ensure you get the feed cycle right. The feed cycle is made up of 2 elements:

  • Feed Frequency – This is how often you feed the plant, which largely depends on what type of growing media you’re using and how well established your plants are.
  • Feed Duration – This is the total time of each feed cycle  and will depend on the number of pot in your system and the growing media used.

Feed Frequency

Fill the reservoir with water and add nutrients as directed by the nutrient manufacturer. Finally, adjust the pH to 5.5-6.5.

Now the nutrient solution is ready, you’re ready to soak the growing medium before planting.

Turn on the timer and initiate a feed cycle.

Set the minute dial for the longest possible feed duration.

As the nutrient solution slowly fills the pots the growing media will take in the nutrient solution preparing the growing media for planting. The nutrient solution will flow through the growing medium and back to the run to waste brain, to be pumped away to waste.

Once the growing medium has had an initial soaking you are ready for planting.


When it comes to planting your young plants you should plant them 1-2 cm into the growing media.

Please note: If you plant to deep into the pot your plants will become saturated causing poor initial root growth.

Setting The Feed Frequency

How often you feed the pots will be determined by:

  • The growing media.
  • The plant size and water requirements.
  • The environmental conditions.

Feed Frequency with Coco / Mix

When using coco and clay pebble mixes, you must use the IWS ‘Culture Pots’. These pots have a net base which has been designed for finer growing media. The bottom portion of the net pot should be filled with clay pebbles. The rest of the pot should be filled with your mix of coco and clay pebbles.

It is important when using coco in a dripper system is to not over-water. For the first 1-2 weeks after planting, while  your plants are becoming established, your plants will need feeding a maximum of once or twice a day. These feeds should be in the middle of your light period. 

When the plants are established and vigorous growth has started, the plants demand for water will increase. It is at this time you should check the moisture level of your mix before the feed cycle or toward the end of your light cycle, if your growing medium is drying you should increase your feed frequency to 2-4 times a day. The first and second feed cycles should be equally spaced e.g. if your using an 18 hour light cycle your feed cycle should be at 6 and 12 hours.

2-4 feed cycles are, in most cases as much as they need, but plants that have a higher water demand may need irrigating 3-6 times a day during peak growth. Remember when irrigating your coco and coco and clay pebble mixes,  ‘transpiration before irrigation’, this means that must be allowed to use remaining water in the growing media before giving them anymore. This is why we recommend having your first feed cycle at least 1-2 hours after the lights turn on.

Environmental Considerations

As with all hydroponic systems, the nutrient strength and feed cycle should reflect your environment. For example; if you’re using clay pebbles and the environment is hot and the humidity is low, these hot and dry conditions will cause the plant to use more water and less nutrient, causing the nutrient strength to rise in the reservoir. In these circumstances we recommend setting the nutrient strength lower than usual to account for rising strength. In these conditions the pots should be flooded more often, up to once per hour.

The same room during cooler conditions, with a higher humidity, will mean higher nutrient strengths can be used and the number of feed cycles can be reduced to once every 2-3 hours. Always consider the effect that the environment will have on your plants and adjust your feeding strategy accordingly.

Maintenance – Avoiding Root Blockages

Because the IWS Dripper system empties through a tube, roots growing out of the pot can cause blockages in the pipe work. This can be avoided by always using the copper root control disks provided and routinely turning the inner pot every 2-3 days in the same direction. This will ensure the roots stay away from the tube and will help to produce more even growth.

If you suspect your pots or pipe work may be blocked, you can check by quickly flooding the pot with 5-8 litre of nutrient solution in from the top of the pot. If the solution drains away freely it’s okay, if it takes a long time to drain you most likely have a blockage. If you have a blockage you should remove the inner pot and check the inlet/outlet tube for roots or debris.

Most system problems are due to not keeping a clean system. You must make sure that float switches in the brain pot do not become dirty or clogged with any growing media or debris. Every time you refill the reservoir, a quick rinse with fresh water over the switches will help prevent problems. If you do notice sediment or debris in the reservoir or brain pot, remove or clean it immediately before a problem occurs.

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