Rockwool Drip System - 08/02/02

3 days since planting onto the slab and the tomatoes are doing very well. At this point I give them each 300ml of nutrient solution at EC 2.2 and pH 5.8. A small amount of run-off drained out the slab on doing this.



I have placed a support cane in the block to prevent any plants from falling over. I will get round to using the roller hooks over the next few days. With the roller hooks the string is tied to the aqua tray and goes up to the roof where the wheel and hook rest on a support bar. This allow the vine to be supported by the string and lowered when they get to too tall.




At this stage it is very important for me to maintain a relative humidity within the greenhouse of between 60-75% with temperatures reaching a maximum of 25-26C. This environment will enable the plants to set off well without being under any stress through excessive transpiration (water loss). The day lengths are still being extended to 14 hours of light using 2 x 400w metal halide lamps.

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.

Ready for Planting - 04/02/08

The tomatoes are up to their 5th set of true leaf's and have loads of healthy roots on the bottom of the cube so they are ready for planting out. I will plant the salad variety 'Cedrico' tomorrow into a rockwool slab drip system and allow the cherry varieties to grow on a week or so more before planting into a large NFT system.


The cucumbers are also ready and need planting tomorrow too. These will go onto a smaller NFT system.

Growing on - 31/01/08

The cucumbers are now needing to be watered with nutrient solution (EC 1.5) every 2 days. The roots are doing really well and can be seen on the top of the block. Without the block covers the roots would not be growing on the block surface. These plants should be ready for their NFT system in about 1 week.




The cabbage are also coming along nicely, they are getting watered from the top (canna coco nutrient - EC1.2) until some run-off leaves the bottom of the pot every 4 days.



The tomatoes are also doing well and the flood and drain table is working a treat. As the nutrient solution get recycled I check the pH and EC every 2 days to keep it the pH between 5.8-6.2 and EC around 18. Tomatoes like higher nutrient strengths in comparison to cucumbers and chillies and I will increase the nutrient strength up to EC of 22 before transplanting onto their final systems.

The chillies and peppers are slower growing but are coming along without any problems. These are still getting watered every 3-4 days. You can generally tell when plants need to be watered by lifting the block. If it feels heavy then leave it alone, each day you will fell it getting lighter until it needs another watering. Knowing when they need a watering comes with practice, the important thing to remember is not to water without checking if the plant needs it.

Transplanting part 4 - 28-01-08

10 days after transplanting the tomatoes and cucumbers the chillies and peppers start to show their roots through the small roockwool cubes and so are moved into the larger 4" rockwool cubes.



To make some space for all the new seedlings I have moved the tomato plants onto a 1m squared flood and drain table. I have made a mesh tray to fit inside the table for the blocks to sit on. This mesh allows the blocks to air-prune while the flood and drain system waters the plants evenly from the bottom.

The nutrient solution is stored in a 80L reservoir and is pumped up through an inlet onto the table where the water level rises to 2cm above the mesh tray where it overflows back into the reservoir beneath. This means the bottom 1/4 of the blocks get wet while capillary action draws the solution through the rest of the block. To ensure even watering you have to make sure the table is level, the legs have adjustable screw feet to make these adjustments.

I timed the first flood (without plants in) to program the digital timer, it takes 4 minutes to reach the desired flood height which is maintained for 1 minute to allow the blocks to suck up some solution. This means the pump should be on for 5 mins. The tomato plants up to now have had nutrient solution through the top of the block every 3-4 days and now have the first signs of roots through the bottom of the block. Now I can put them on the flood and drain table and program the digital timer to come on every 3 days to flood the table at 12:00. As the plants get bigger this will increase to every 1-2 days. In the past I have watered by hand but when you've got over 100 plants to do every day it can take up allot of time. These tomato plants should be ready to planting out in 7 to 10 days.