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.
