Rockwool Drip System - 12/02/02

The tomato plants are now firmly rooted in, a light twist of the 4" block shows they strongly held to the slab. I have removed the canes and strung the vines up with the roller hooks. Now the plants are ready the drippers are inserted into the block and i set the digital timer for the irrigation pump to come on for 3 minutes every 2 hours while the lights are on or sun is up. I set the first irrigation to come on 2 hours after the lights come on and the last 2 hours before the lights go off. On these first and last irrigations they get 6 mins.

The nutrient solution being given to the plants now is Vita-Link 'Easy Grow' at an EC of 2.5 and pH of 5.8. The general rule of thumb for drip systems is 'transpiration before irrigation' so i start the irrigations 2 hours after the lights come on knowing at this point the plants are taking up nutrient solution for the slab. I make sure on each irrigation that some solution drips out the slab, this run off wants to be around 20-40% of the input volume so if you give a slab 1ltr you want to see around 200-400ml of run off. The easiest way to check you getting enough run-off is by time, if your irrigation length is 3 mins then you want to see the slab getting run off after about 2 mins after the pump comes on. The picture shows the high pressure filter set in the nutrient reservoir, i keep the overflow valve open slightly so on each irrigation the soultion will mix and aerate.

I have covered the run-off tank with some black plastic corriboard to prevent algae growing in the open water. All i have to do now is make sure the reservoir is topped up with nutrient solution and empty the run-off tank once a week.

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