Irrigating with rainwater - it's not all about free water

With the wettest summer on record has come the benefit of plenty of free water. Chisholm's glasshouse roof provides the perfect mechanism for harvesting rain water which is piped in to our storage tanks. With a storage capacity of some 200,000 litres of water, we were certainly surprised to have seen our tanks at full capacity a couple of times this summer!

But although the water is plentiful at the moment, it has some inherent problems. The pH value of the rainwater is around 6.2, but we have found that once we add our A and B solutions of fertiliser, the pH changes to a value of 4.2. This is not good for plant growth and can cause root damage.

The reason for this is that the rainwater has no 'buffering' capacity. In basic terms it is too soft. To counter this we are now injecting Potassium Bicarbonate in to the irrigation water through the Powerplants Nutrimix Fertigation system.

Powerplants Nutrimix Fertigator

The Nutrimix links directly in to our Priva Integro system which is now allowing us to have a finite amount of control on the irrigation water content. This now means that after treatment our water is being supplied to the plants at a more acceptable pH value of 5.6

But just supplying water is only half the story. We are also monitoring our gro slab moisture content, pH and EC rates, as well as recycling the irrigation water and sterilising it as well. But more on that side of our system in a future blog entry!