This 'Flood and Drain' system is very popular with hydroponic growers who like the flexibility of growing in pots with the added benefit of an automated irrigation system that recirculates the nutrient solution. The system is made up of 4 main components, the reservoir, the 'brain', the timer and the pots. The system works by periodically filling and draining the pots from the bottom with nutrient solution. It does this by switching on a pump in the reservoir that fills the brain unit. All the pots are conntected to the brain so as the brain fills so do all the pots. When the brain is full a float switch is activated which turns off the pump. Once all the pots have been flooded a pump in the brain is activated which drains all the pots by pumping the solution back into the reservoir. The IWS (Inteligent Watering System) is made by Direct Garden Supplies in Sheffield, UK. This pot based flood and drain system has been around for many years and was originally brought to the UK market by 'Highlight Horticulture' in Nottingham which they call the 'Multiflow' System.
The IWS system is very easy to set up. First thing i do is set place the pots in position. The pots are made up of 3 parts, the stand, the outer pot and inner pot. The stand has small inbuilt slope that allows the pot to fully drain. The inner pot has loads of holes the the bottom, this is placed inside the outer pot.
Once the pots are put together the sealing gland needs to be attached. This has 2 parts, the nut and rubber sealing gland. The gland on the outside of the pot needs to be very tightly screwed to the nut on the inside of the pot. Once the gland is in the connection tee or elbow needs to be inserted through the gland and tightened. This will form a water tight seal through which the pot will fill and drain. The same glands needs to fitted onto the brain and straight connectors need to be fitted. This will enable the brain to be connected to the pots with flexible 16mm pipe.
When connecting the brain to the pots i always heat the pipe in hot water before pushing onto the barbed connection pieces. Also, i always lay some extra pipe between the pot and the brain which i loop betwwen the pots as shown in the picture. I do this for a reason, when the plants are small i group the plants close together and as they get bigger i pull them further away from each other. The extra pipe work allows me to do this. If i knew the plants were staying in the same position i would cut exact lenghts to join the pots to the brain. After all the pots are connected i attach the timer to the brain and mount the timer on the wall in an easily acessible place.
Now the system is ready i get the clay pebbles ready for planting into. The pebbles im using have already been used last year so i have soaked them for 24 hours in a water with hydrogen peroxide(aka Oxy Plus) added at 50ml per L. Although i didnt have any problems last year the peroxide should kill any nasties that may be lurking around. After the soak i lift them out using the inner pot and then rinse them thoroughly with tap water.
Once the clay pebbels are thoroghly rinsed i fill the pots three quarters full. Then i fill the 220L reservoir with water and add 22ml of Vita-Link Bio-plus and Vita-Link Max Grow A+B nutrient to a EC of 1.5, i then set the pH to 5.8. Now the nutrient solution is ready i turn on the timer and start a flood cycle. As the soultion slowly fills the pots the clay pebbels will take in the pH balanced nutrient soultion and the beneficial bacteria (from the Bio-Plus) preparing them to be planted into. If you only wash them with tap water and plant straight in the pH will be too high in the pebbles which could cause some inital nutrient uptake problems.
I want the maximum flood height to be the same level as the clay pebbles so i watch the pots filling untill i can see the water level raising to the surface. As this happens i push down on the pebbles with the palm of my hand to make sure the pebbles arn't floating. As the water rises i keep adding pebbels utill the water level is the same height as the pebbels. When the the brain stops filling and all the pots have the right amount of clay pebbles and solution in, i leave them soaking in the nutrient solution for 1 hour.
After the 1 hour soak i initiate the drain cycle on the timer. Once the drain cycle is finished i get my stop watch ready on my phone. I start another fill cycle and start my stopwatch to time how long it takes for the pots to fill back to the max flood height. It took 4 mins to reach the desired height and i want the flood height to remain steady for 1 min. This allows the rockwool block to draw up nutrient solution by capilary action. This means i should set the timer to 5 mins. Now i know the desired flood duration i plant the blocks into the pots by placing them 1 pebble deep in the pebbles so the flood height will reach the bottom quater of the block as shown in the picture.
Once they are planted in i fill the top of the pot with pebbles and set the timer to 1 flood a day for a 5 miute flood duation.Once the plants are settled in I'll support them with strings. Hopefully all will go well.
very informative, thankyou
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