Grit

[habanerocat]

Using the standard 50/50 John Innes No.2 and grit, what's the best type of grit to use?

Limestone aside this is a very general question as I'm trying to source some locally and am looking at either granite or sandstone. I've seen cacti potted in granite and it seems to go off green over time. Kind of puts me off. The bagged grit in the garden centres seems to be kind of a sandstone marble mix, whereas the sandstone I can get locally is very powdery.

Easier get the bigger stuff as it's used in driveways. Harder to have much choice down to the 5-8mm range.

Which is best?

[Chris L]

Using the standard 50/50 John Innes No.2 and grit, what's the best type of grit to use?

Limestone aside this is a very general question as I'm trying to source some locally and am looking at either granite or sandstone. I've seen cacti potted in granite and it seems to go off green over time. Kind of puts me off. The bagged grit in the garden centres seems to be kind of a sandstone marble mix, whereas the sandstone I can get locally is very powdery.

Easier get the bigger stuff as it's used in driveways. Harder to have much choice down to the 5-8mm range.

Which is best?

I've always use(d) granite - it is sort of a pinky colour. Never had any problem of it going green .

Some people seem to like using round pebble shaped sandy coloured grit - almost like aquarium gravel - but I've never really liked that stuff.

[ralphrmartin]

I use granite grit (from the local quarry here in North Wales). It certainly seems to suit the South American cacti.

[edds]

I buy bags of 4mm horticultural grit and really like it mixed 50:50 with JI. It certainly isn't looks very much mainly igneous rock but exactly what types I've never bothered to try and identify.

But the cheapest I have found is about £4 per bag from my local garden centre. Does anyone know of a cheaper source? I'd happily buy ton bags!

[NickHitchcock]

We could start a thread for these "Terry Smale said" use angular granite as it helps with drainage.

[el48tel]

Granite grit ..... 2 to 6mm ...... stones 4 homes ..... from City run garden centre .... £12 for 3 bags

[FredG]

I'm down to my last bag of the granite grit from Aldi

[Brian]

Jondo do a very good range of grit of different sizes. OK if you can find a supplier locally to pick it up, perhaps an agricultural supplier. Delivery probably triples the price!

jondogrit.com

The four flint grits.

[habanerocat]

I use granite grit (from the local quarry here in North Wales). It certainly seems to suit the South American cacti.

But not North American cacti?

[habanerocat]

Granite grit ..... 2 to 6mm ...... stones 4 homes ..... from City run garden centre .... £12 for 3 bags

Almost twice the price over here unfortunately. So looking for a bulk source.