Does Spraying Milk On Courgettes Prevent Mildew?

I hear this home cure whenever mildew starts to strike marrow and courgette (aka zucchini) crops. But does it really work? The answer might surprise you.

Sadly many garden myths and home cures are without any form of basis. Someone says x,y or z works and it gets repeated over and over again. People tell their friends, they see it on websites and in articles. Sometimes it even gets repeated by TV gardeners. But none of this makes it true!

The thing is repetition doesn’t make it true. And your friend saying they tried it and didn’t get mildew proves nothing. Perhaps they wouldn’t have got mildew on their crops anyway.

What is required are objective trials that can be repeated and are verifiable. We need to grow some courgettes, spray some with various dilutions of milk and see what happens.

If none get mildew, or they all get mildew nothing is proven. But if the control courgettes, those that don’t get sprayed with milk, get it and the others don’t, they we are onto something.

Fortunately we don’t need to trial to discover the answer to the question Does Spraying Milk On Courgettes Prevent Mildew? Someone has already done it.

Wagner Bettiol researched this (1999) and published a paper entitled “Effectiveness of cow’s milk against zucchini squash powdery mildew (Sphaerotheca fuliginea) in greenhouse conditions”. Bettiol says “High concentrations of milk were more effective than the conventional fungicides tested. This study demonstrated that milk is an effective alternative for the control of powdery mildew in organic agriculture.”

What About Pumkins?

And based on his research theres more research on a related vegetable crop, pumpkins.

In 2007 Francis J.Ferrandino & Victoria L.Smith²    published their research on the subject.

Entitled “The effect of milk-based foliar sprays on yield components of field pumpkins with powdery mildew”. They said milk was better than baking soda at reducing mildew. and that skimmed milk was inferior to full fat milk. They also said that fungicides were much better than milk. They also say results are highly variable. 

So, Does Spraying Milk On Courgettes Prevent Mildew?

It appears it might in some cases. The evidence is a bit patchy but it is there. However we need to realise that these trials were both overseas in conditions unlike ours in the UK. But, based on them, I’d like to see more trials and I certainly think that if you see impending mildew it is worth a try.

So, yes Spraying Milk On Courgettes Does (sometimes) Prevent Mildew?