Beware Of The Mix Up
By Chris Humphrey MBPR FQA, Technical Manager
I don’t know how many times I have heard someone say “I was told I could mix these things in the spray tank”
Before you mix anything in the spray tank you must first ask yourself what am I trying to achieve? Some things just do not mix chemically, some things will mix but one may well deactivate another; sometimes what mixes well may have an inappropriate water volume.
When applying a fungicide, do you put a bit of iron in the mix? It gives you colour and dries out any mycelium but most iron products will not tank mix with such active ingredients as they react badly due to the acidic ph. In addition most iron products contain sulphates which can react.
This reaction produces insoluble precipitate sediment which forms a sediment in the spray tank. This can block the sprayer, nozzles, pumps and pipework, and render the products ineffective. This can also result in uneven spray applications.
Tank mixing can be a great timesaver but only if your active ingredients are going to do what you want them to. For example, do not mix a foliar feed with a wetting agent. Although they may mix quite nicely in the spray tank, the wetting agent is designed to get into the soil and it will take the foliar feed with it. This is not ideal as you want the foliar feed on the leaf and you will get no response from it if you take it into the soil.
You may be told that by adding something to the spray tank it will improve the performance for your chemical. That is an Adjuvant. An adjuvant is officially defined as materials other than water that increase the effectiveness of an active ingredient but have no biological activity in themselves. For a product to be classed as an adjuvant it must be tested, registered and have an adjuvant number.
For all advice on tank mixing, you must ensure you consult a BASIS qualified advisor. You don’t want to end up with a tank full of jelly where chemicals react or render your expensive fungicide useless by adding an inappropriate product.