Just wondering if rooting hormone in powdered form has a shelf life. I bought my tub over 5 years ago now. Still loads of it left but does it go off over time? There is no 'best before' date on it.
Perhaps the following link might explain:
This is a working version of the link.
The gist of it is that rooting powder is practically useless, I have always used it but haven't any way of telling whether it works - I have put my failures down to poor technique!
There are two main rooting compounds, indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA). You can buy only NAA in garden centres, usually in powder form but sometimes as a gel. IBA is preferred by commercial growers and harder to get hold of- I have bought some on-line - think it came from the USA - was it called Clonex??
I am no expert by any means, and am ready to be contradicted, but from what i understand, the shelf life for NAA in powder form is around four years. It often contains a fungicide and this element may have a shorter life span. I think that the liqquid version of NAA is a lot less - a year or so, but am not sure as to why.
I understand that IBA has a shelf life when dry of three years, but is usually applied wet, either in alcohol or water, and like NAA, in this form its shelf life is a lot lower.
Thanks for the replies. Yes it is NAA that I have. It may be time then to replace it. Or I might try a batch of cuttings without using it as suggested in the link you provided to see if they root anyway.
I recently potted some cuttings of cineraria silver dust, half using hormone rooting powder and half without, as an experiment to see if they differed. All seem to have taken and are looking healthy. Not conclusive proof, but will try this again for comparison.