Setting up an IWS Flood and Drain system - 20/02/08

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.

Setting up an 'Autopot' system - 19/02/08

This hydroponic system is one of my favorite systems to use in the greenhouse because its so easy to set up and takes very little care and attention to maintain it. 'Autopot's' come in 2 variations, the 1 pot system (pictured left) and the 2 pot system (i will set up later this month). The 1 pot can be set up to one small reservoir or you can link up multiple pots to one larger reservoir as i will be doing here. The one pot module consists of a square 15l pot, base tray and lid, one 'aqua valve', 1.5m 4mm flexible tubing and 2 root control mats.

The autopot is a simple yet clever method hydroponic growing. The 'aquavalve' lets nutrient solution fill the base of the pot to a depth of 20mm, once it has filled to 20mm the valve shuts off. The plant will then use the solution in the base of the tray until there is none left, once all the solution is used the valve refills the tray to 20mm again. The is all done without the use of electricity and you dont need any pumps. This system is described as 'plant driven' as the plants uptake drives the irrigation.

The autopot comes with very clear instructions that are easy to follow. One very important factor in setting up is making sure the aquavalve is set properly. The picture shows 2 valves, the one on the right is set correctly while the one on the left is not. You can tell by the the way the float is sitting lower on the left valve than the right. To set the valve simply pull back the top float and remove the yellow rubber, clean it and push it back in firmly. Job done.


Once the valves are set attach the 4mm tubing to in and fit the valve in the base tray by allowing the raised tee on the base to sit in the half moon recess on the valve. This will allow the valve to sit securely in the tray. I'm connecting 4 Autopots to one 1ooL reservoir although this size reservoir could feed up to 10 pots without a problem. The reason i use a large reservoir is so i can leave if for long periods without having to keep topping it up. To connect to 4 Autopots to the tank i use 3m of 13mm flexible pipe, a 'Hoselock' tap connector, two 13mm>4mm 'X connectors' and one 13mm flow control tap. In the picture you can see the Hoselock connector attaches to the tap on the reservoir which is attached to the 13mm pipe. The 13mm pipe runs between the pots with the 'X connectors' in position to connect the 4mm tubing from the aquavalves to the 13mm pipe. At the end of the pipe i fit a flow control tap and keep it closed, i will occasionally open this tap at allow and residue build up in the pipe to be flushed out. Notice the reservoir is raised on a stand to use gravity to increase the pressure to the valves.

Now the pots are connected i place the root control mats in , the copper one goes in the tray copper side up and the black one goes in the pot. On top of the black mat in the pot I put a layer of clay pebbles about 3cm deep. This will stop the very base of the pot from getting waterlogged. On top of the clay pebbles i use a mix of coco coir and perlite (20% perlite to 80% coco coir). I am growing a variety of chilli in the autopots called Joe's Long. These have been propagated in rockwool blocks. On planting I bury the bottom third of the block in the coco/perlite mix as shown in the picture.



To finish it off i fill the top of the pot with clay pebbles and cover the rockwool block with a block cover. These pebbles on the top of the pot will help to insulate the pot and will stop the top layer of coco/perlite mix getting dried out by evaporation from the sun or grow lights. Once the plants are in i hand water them from the top with Canna's coco A+B at an EC of 1.6 and a pH of 5.8. These plants will get hand fed from the top for the next 2-3 weeks until i'm sure the roots have made their way throughout the entire pot and the plant is ready to be fed through the valve at the bottom. If you start by feeding from the bottom straight away quite often the plants small root system cannot cope with the saturated growing medium and will get off to a slow start. By hand watering every 2-4 days for a few weeks you will get the plant ready quickly for bottom feeding. I have filled the tank with nutrient solution but have kept the tap on the bottom of the reservoir closed, this way i can top feed the plants with a jug out the reservoir when they need it.

Cant wait till I've got some lovely long hot chillies in a about 3 months time. I find chillies and peppers the best plants to grow in Autopots, although I've had good success with melons, and tomatoes too.

Setting up a Hydroponic NFT Multi Duct- 15/02/08

This Hydroponic system is a large NFT 'table' made by Nutriculture and is know as the 601 Multi Duct. These systems come in various sizes and configurations, this 601 is about 2m x 1m with a 125L reservoir. With this system a submersible pump (maxijet 500) is positioned in the tank at the drainage end and pumps nutrient solution up the middle of the tray through 1/2" supply tube where it splits at the top through a tee piece into 4 outlet fittings (2 x tee's and 2 x elbows) where the solution enters the top of the tray. From here the solution flows down the tray and drains back into the tank. The tray is supported by a stand at the top end and the tank at the drainage end giving the table a slope of 1 in 50. This type of recirculating hydroponic system is great for growing all types of plants, I'll be using it this year to grow my favorite mini plum tomato called 'Floridity'.


After setting the system up and fitting all the pipe work i run through a solution of Hydrogen peroxide at a dilution rate of 50ml per 10L for about 4 hours. This will sterilise system killing any bad bacteria that may be lingering from last year. Once the system is clean i lay down the spreader mat which helps to keep the flow of nutrient solution even down the table.






Now i fill the tank with water and add Vita-Link 'Easy Grow' at a EC of 2.0 and pH of 5.8. Once the tank is well mixed i turn the irrigation pump on. The Nutrient solution will flow quite rapidly if you have the pump on full so it has to be adjusted down using an inline flow control tap which i position near the pump in the tank. I turn the tap to adjust the flow rate so the solution lands in the first channel as shown in the picture. Once the flow rate is set i leave the pump running 24/7.


Now the system is running i get it ready to be planted into. Using a black corriboard i cut holes out where i want my plants to be. Notice i stager the planting to allow good water flow down the table. Once the holes are cut i cover the whole table and tank with black and white sheeting (white side facing up) to help insulate by reflecting and light away from the root zone and tank. I cut an X on each hole to allow the plants to be planted through the black and white.





On planting i have tied the roller hook string around the 4" blocks like i have when i set up the 604 gro-tank with the cucumbers and hung the hook from the roof supports. This will allow me to train the vine up the string for support. Now the plants are in and the nutrient solution is flowing all i do now is monitor the solution in the tank every few days to keep the pH and EC in range. As the nutrient solution is recycled i expect to completely change the solution every 7-14 days. Cant wait for my first harvest which i expect will be in 8-10 weeks!

Setting up my Rockwool Drip System Pt 2- 05/02/08

Setting up the pipe work for the drip system is fairly quick and easy. Make sure you have a kettle on standby as every barbed fitting you push over rigid plastic pipe needs to be heated in hot water first. This makes the pipe hot and so expands allowing the barbed fitting easily slide over, when the pipe cools it sets around the barbs making it a good water tight fitting. With the compression fittings the blue insert is barbed and is then tightened by screwing the sheath to the cap. I start the pipe work at the far end with the stop end. The piping in then cable tied to the support bar all the way along. From the support bar the the supply tubes goes through 3 elbows and up to the filter set in the 220L reservoir.

Once the supply tube is in place and attached to the filter set I can start to install the drippers. Using the hole punch I cut out the holes carefully.






Once the hole is cut get the pre assembled dripper and insert it into the tube. You should hear a 'click' as it goes in. Once in pull the compensator back while squeezing the supply tube. This will help form a tight seal. I use 1 dripper per plant some growers use 2 or more but this is not necessary.


Now all the pipe work and drippers are in place I now position the plants on the trays. I am using 2 plants per tray in the middle and 3 plants per tray on each end. Last year I put 3 plants in every tray and I found the plants in the middle of the system did not do well as the were mostly in the shade.

Once I get the spacing and positioning right on the upside down slabs I mark out with a permanent pen on the slab bag where the drainage slits will be cut. I also mark on the aqua tray where the plants will get placed.

When I cut the drainage slight I'm careful not to cut into the rockwool slab. The drainage slits need to be diagonal and between plants not underneath them.




Once the drianage slits are cut its time to flip over the slab. You may notice I have cut the slit to fill the slab at the top of the tray instead the bottom. This is not a big mistake, all I have to do is flip the slab round so the horizontal slit is at the drainage end. Once the slab is flipped it will drain some more.




When the slab stops dripping its time to plant on. I cut an X on the slab and lift up the flaps. The plant is then placed on the slab and about 200ml of nutrient solution is poured through each block. This will be the last irrigation they get for 3-4 days as the slabs and blocks hold all the solution they need.




Over the next 3-4 days the roots will find their way into the slab and a light twist of the block will show you how well the plant is rooted in. In 1 week it will fell very solid on the slab and the drippers will go in to start irrigating the slabs. I will also make a cover for the catchment tank to prevent algae growth.

Hanging above the drip system is 2 x 400w metal halide lamps. The lighting system I am using is the 'Aurora Gemini' with 'Rising sun' reflectors. This system has 2 ballasting units in one case. The unit also has a built in contact relay so all I do is set the timer on the ballast and plug it in using 1 plug. Save on valuable plug points and is neat and tidy. The lighting extends the day length to 14 hours of light coming on at 7:00am and off at 21:00pm

Setting up my Rockwool Drip System Pt 1- 05/02/08

Now my 'Cedrico' tomato plants are up to size and have a good root system showing out the bottom of the block is time to set up my high pressure drip system where I'll be growing the plants on 1m rockwool slabs. I have 20 healthy 'Cedrico' plants all of which I'll be choosing the best 14 for the system.





To start with I have placed the 1m grodan 'expert' slabs in their plastic trays (know as aqua trays). I insert the slabs upside down and place the trays on top of the catchment tank which is just over 2m in length. I have also made a support bar which is 2.3m in length which you can see behind the tank. I also turn the drainage tubes at the end of the tray to face up so any excess solution stays in the tray.

Now the slabs are on a flat surface I cut a slit at the drainage end of the tray and fill a 100L tank with nutrient solution at a strength similar to what the plants have been getting feed over the last few days, EC 2.2 with a pH of 5.5 using the Vita-Link 'Easy grow' 1 part nutrient . I also add in to the solution some Beneficial Bio-Link plus which will help establish a good root system. From the storage tank I fill a watering can and pour the nutrient solution into the slabs through the slit until the slab is fully saturated throughout. The slabs are then left to pre-soak for around 12 hours.

While the slabs are soaking I get the pipe work ready. For high pressure drip systems I use 3/4" supply tube with 3/4" compression fittings. For this system I need 4m of supply tube, 1 compression 'stop end' and 4 compression elbows. The tubing will be attached to the support bar at the top end of the slabs running up the the blue 220L nutrient reservoir.

In the reservoir I have a 4000lph WGP55 little giant pump attached by 3/4" tricoflex hose to a high pressure filter set. The filter will help the drippers from clogging and also can be used to regulate flow and mix the solution in the reservoir.

This picture show the fittings needed to join the pipe work together. Cable ties come in handy to attach the pipe work to the support bar keeping it off the floor.



The drippers I will be using are called know as high pressure self compensating drippers. These drippers have a small brow compensator that plugs into the supply tube and is held with a barb to stop any leaks. These compensator's have a small diaphragm inside which makes them only open under pressure when the pump is on. When the pump goes off the pressure drops in the supply tube and the diaphragm closes. This means that each dripper acts like an anti-siphon valve stopping any through flow of water. The green tool is a hole cutter to make a hole in the supply tube to insert the compensator into.

Now the slabs have been soaked for over 12 hours i turn the drainage tubes down and position the slabs so one end is on the support while the other end is draining into the catchment tank. The catchment tank is weighted with bricks to stop it from turning up under the weight of the slab.

Once the slab stops dripping I remove them from the stand and turn up the drains up again so the trays can be placed on the floor so I can start attaching the pipe work. The support bar is about 1.5cm higher than the catchment tank to give around a 1:100 gradient to the slab to allow the solution to drain out. Some slab trays come with an inbuilt gradient, like the 1.3m aqua tray. This drainage gradient is important as too steep will give a wet end and a dry top while too shallow will keep the whole slab too wet.

Setting up an NFT Gro-Tank Pt 2- 05/02/08

Once I know the flow is perfect down the tray its time to cut out the planting holes in the corriboard cover. The corriboard prevents any light reaching your roots and can help all a bit of support for your plants. I am using 4 plants in the 604 and 1 plant in the 205i.

After cutting holes in the corriboard i cover the top of the tank with black and white plastic sheeting white side up. This helps reflect back any light and heat helping to keep your roots and nutrient solution from getting to warm.


To support my cucumber plants i use roller hooks which are a spool of string on a wheel attached to a support hook. The vines are trained up the string and when they grow to up the wheel more string is let out lowering the vine. This support hook is then moved along so the excess vine at the bottom rests on the corriboard. Using this technique one my cucumber plants last year was over 12.5 metres long. Another popular way to support plants on NFT systems is using pea and bean support netting which is stretched out horizontally on a frame above the plants so when they grow into it the are supported by the net.

Once the roller hooks are in place I tie the string to around the rockwool block. The positioning of the blocks on the tray is important, you want to stagger you plants so solution can flow down the middle of the tray and around all side of the block. You also need to position the blocks so that the solution can flow trough the grooves on the bottom.

Now I place the corribaord and black and white sheeting back on the tray and lower the plants into their pre cut holes. I cut the black and white in a x so the folds can be repositioned over the top of the block to prevent algae growth.




Now that the plants are in the system I add nutrient to the reservoir at an EC 0f 1.5 and a pH of 5.8. The pump is plugged in and will be let constantly running 24/7. Some grower put their NFT pumps on a timer so it comes on for 15mins and off for 15mins to half and hour. This is not the way NFT should be run but some people growing plants with more sensitive root systems or use larger blocks to propagate the plants find it helps.

The plant in the smaller 205i system is also getting irrigated 24/7 with the same pH and EC of the 604 system. These cucumber plants should settle in and start growing vigorously in the next few days. Hopefully I should be picking my first fruits in around 6 weeks time.

Setting up an NFT Gro-Tank Pt 1- 05/02/08

These cucumber plants are now just over 3 weeks old and are ready to go onto their final system which use the Nutrient Film Technique or NFT.






The most important thing about getting plants ready for any hydroponic system is that they are well established in their propagation block having loads of healthy white roots.






These are the Gro-tanks I will be using, the small one is the 205i and the other is a 604. They are made in UK by Nutriculture who make 5 different variations in size. The top tray is where the plants are placed and the reservoir underneath holds the nutrient solution. The 604 holds 60L and the 205i holds 20l. The idea behind NFT is that the plants on the top tray spread out their roots into a thin film of nutrient solution which is constantly flowing. The solution is recirculated from the reservoir, down the tray and back into reservoir at the other end. The roots eventually grow into a thick mat nourished by the nutrient solution and highly available oxygen all around them.

The NFT Gro-Tanks have one delivery tube where the nutrient solution is pumped onto the tray. To ensure even distribution of water on the tray capillary matting know as 'spreader mat' is rolled out. 1 layer is enough and a small over lap in the middle is fine. Once this has been laid out I fill the reservoir with water.

Once the tank is filled I submerse the pump and attach the delivery tube and turn it on. The pumps have an adjustable flow rate and need to be slowed down so the solution lands in the middle of the first diamond.


After a few mins all the spreader mat should be wet. If you find some dry spots then poke the spreader mat down into the channels to wick up the solution. If there is little or no solution flowing in any of the channels make sure the tank is on a level floor and the flow rate is right until the solution is reaching all parts of the tray.

If you flow rate is too high then you solution will puddle. This will cause the plants roots to get over watered which may cause them to be starved of oxygen. Too much flow will also cause the rockwool blocks to get completely saturated which will get you plants off to a poor start.