Sharp Sand - how good is yours ?

In his weeks Amateur Gardening mag there is an article by Peter SeaBrook where he has laid down a sand bed for various plants and it shows a picture of a bag of B&Q Sharp Sand which he says “needs a ph 6.0 – 6.5 “

It might be a local problem ( though I doubt it ) but if anyone has tested a bag of B&Q or any of the other big diy stores in the last few years you will find that unlike what was known more sharp/ river / grit sand some years ago, it has now become a much more crumbly / powdery mix with a very high ph.

So using this kind of sharp sand for lawns, general lightening of the soil or potting compost will result in a high ph that can literally kill off some plants, as I eventually found out to my own cost in a small boarder that I has used some such sand to lighten it, but then very few plants grew well for the next two years before I tested the ph and realized the problem.

You can easily check if your sand is Neutral ph 7 by getting a small freezer bag , placing a tablespoon of sand in it, followed by a tablespoon+ of ordinary vinegar.

Anything neutral or below will not cause a reaction, but if its alkaline then everything will start to fizz and bubble .

This page gives more detail of diy ph testing http://preparednessmama.com/testing-your-soil-ph-without-a-kit/


I did email some magazines with this info the other year , but seems it fell on deaf ears.



Below are some readings I took with a proper ph meter of other mediums

Local Builders merchant
True Sharp Grit Sand 8.2


Wickes 10mm gravel 9.9
rinsed in DI water

RHS Potting Grit Lime Free
out of bag 9.3
rinsed in DI water 7.0

 

Very interesting, thank you for posting that

Try again

 

Thanks for that info! I have also found that many bags of 'grit' are rather muddy and powedery, but I didn't realise about the pH being so high.

 

Very interesting thread

The pH levels of some of those bags is bordering on garden homicide. The RHS product is the most disturbing as it is advertised as lime-free. Maybe they didn't add lime but the alkalinity is so high that it's a complete contradiction to what it is sold as. Talk about false advertising! The RHS is the most trusted of all UK gardening associations and they should know better

Keep trying to contact magazines as people need to know about this. The only problem envisaged is that gardeing mags may be reluctant to dish out any dirt on the RHS as they're a formidable force.

Some mainstream newspapers may though; it could be quite a scoop in their gardening section: "RHS is Tring to Kill Your Garden!". That is if the article authors aren't the usual bunch i.e. Monty Don, Alan Tichmarsh, Carol Klein, Charlie Dimmock etc.

 

In fairness, it wasn't the RHS I was warning against, its the horrible stuff the DIY Stores now sell as Sharp Sand, which as that AG article shows, many folk will buy thinking its fine for their garden and plants.

The RHS grits high ph out of the bag is probably dust from the manufacturing process as a quick rinse in DI water soon proves it has a ph of neutral 7.
Because it washes away so readily I expect the first watering would clear it and not affect the plants.
However its still a slight disappointment to do that when paying a premium price for the product.

I had originally bought the Wickes bag of Grit for adding weight to some Fuchsia pots and some Blueberries pots, but glad I tested its ph as it could have been a problem.

Bought a small bag of "Horticultural Sand" the other day to use in a compost cutting mix, be interesting to see what thats measures.

 

I've only ever used sharp sand from builders merchants the so called horticultural stuff is far too over priced in my opinion.

I only every use it as an addition, never neat, so any alkalinity is presumably diluted by whatever I'm adding it to, as I have never had a problem.

Must admit I've never even considered adding it to anything which likes acid conditions, as for the most part, anything that I'm likely to grow which is ericaceous, will probably prefer the more peaty leafmould type conditions rather than acid sand.