Do fertilizers get old?

[lady slipper]

I have a bottle of phsan I have had for years. Maybe as long as 10-15 yrs?
It has always been caped tight but my question is? Is it safe to rely that this
bactericide is still safe and viable? Is it necessary to get new product?
thanks
lady (guy) slipper

[madphrag]

Physan 20 is not a fertilizer. It is a relatively broad spectrum fungicide, bactericide and overall sanitizing agent, to put it briefly. I'm not familiar with the shelf life of this product, even thought I do use it occasionally and keep a 12 oz spray bottle within reach for spot treatment . As far as any fertilizer mixes, (NPK, minor elements, etc.) my understanding is they are all very stable even after being dissolved in water if kept tightly sealed. In other words, don't worry about it.

[lady slipper]

I do know that Physan is not a fertilizer. I guess I was just lumping all the chemical stuff
together for the same question- that of longevity. But you answered it well for me and I
just won't worry about it and go ahead and use it. And so far the plants have been doing
OK (new rooting takes a bit of time anyway). Thanks
Lady(guy) slipper

[richardb]

Physan is excellent stuff - so much so that the UK Dept of Farming has BANNED it here, as with so many other excellent amateur garden chemicals. Cannot get anyone to say the reason though.
We are searching desparately for a substitute.
Richard