Helen Harris: Water hardness has a big impact on effectiveness of sprays

Grain farmer Helen Harris on her farm in Co Kildare
Grain farmer Helen Harris on her farm in Co Kildare
Stock Image: GETTY
Helen Harris

Helen Harris

When spring tried to get going, it was as though Mother Nature forgot about it and moved straight into summer.

With the fantastic sunny days, the whole country seemed to come alive. I even saw a couple of lads out in shorts, in February.

Every machine that had been gathering dust all winter was out and moving. Fields were ploughed in great conditions and the only complaint was the price of seed and fertiliser.

I did hear one farmer say that there was an old Irish proverb along the lines, that if the cattle have plenty to eat in February, they will have nothing to eat in May. I wouldn't be that pessimistic, but I do realise that the winter is not over yet as we all found out last weekend, particularly in this part of the country.

It was all work with us too in the last few weeks. We had cover crops that needed spraying off and spring barley to sow. All the winter crops are looking hungry and we need to get fertiliser out.

This mild weather doesn't help with aphids either. They need to be carefully monitored as well as the warm weather diseases. I have heard that there are serious rust pressures on winter crops this year.

I went to a talk given by Whelehan Crop Protection about oats and the importance of water, when it comes to spraying. As we don't grow oats, I found it really interesting and I think we may have to look at growing oats again in the future, especially as we are now into crop rotation.

I had heard that different water can make a difference to the active ingredients but I didn't appreciate just how much difference is involved.

Get the latest news from the Farming Independent team 3 times a week.

When they had the various bottles of water in front of you it really was an eye opener in terms of the difference water can make to the active ingredients.

The big take home message was the importance of knowing the hardness of the water. This is the measure of lime in it. The pH is much less important. If it does have a lot of lime, it is probably having a negative effect on the active ingredients of the chemistry in the sprays.


Water conditioners solve this problem by binding to the calcium and other elements including iron or magnesium. By binding to the trace elements, they don't allow them to interfere with the chemistry in the spray.

Glyphosate is one example of chemistry that is not as effective with high levels of calcium (lime) in the water.

Some glyphosate products already come with water conditioners added, but others don't. Many other products, including herbicides, benefit from water conditioners.

The order in which you fill the sprayer is very important. It should be filled one quarter full with water, then add the water conditioner.

Fill to 90pc full of water and then add the spray. Top up with water. I'm not sure how practical that is when you have a heap of sprays to get in and triple rinse each bottle, but that's what's recommended.

The other message was the amount of water that we use will also have a bearing on the chemistry. If you reduce the water rate or the chemistry rate, then you should make sure you change the conditioner rate accordingly.

The second product that is important to improve the 'wetness' of water are adjuvants. When a drop of water was dropped onto a plastic sheet, it covered a very small area and sat upright on the sheet. When an adjuvant was added it spread flat and covered about seven times the area. It was a useful visual example of what happens when spraying.

Adjuvants are particularly helpful when spraying a leafy crop like oil seed rape or potatoes. I'm not endorsing any product, but I do think water is something many of us take for granted and it is only when you see the variations that you realise just how important it is when spraying.

Philip and Helen Harris are tillage farmers in Co Kildare. Follow them on Twitter P&H Harris @kildarefarmer

Indo Farming

For Stories Like This and More
Download the Free Farming Independent App