Used Vermiculite?

[Nicos]

I've not really worked out which potting compost to buy over here yet for sowwing seeds. (It seems to be either very fibrous or peaty- French Grapes please suggest what you find works best!!!)

And so- we've used vermiculite mixed in and had much better results
BUT

Normally I chuck spent potting compost onto the beds but vermiculite seems to stay in the soil.
I can see that in years to come it'll build up in the top soil.
So....what do other peeps do who use vermiculite? My soil is already sandy so I don't need the extra drainage it provides.

[Aberdeenplotter]

Vermic also holds moisture so if your soil is sandy, the vermic will be very useful indeed

[Nicos]

Oh good - daft ol' me thought it was just to lighten the potting compost to allow better drainage!

[VirginVegGrower]

Good ole AP - I never knew that either. What would we do without you

[Aberdeenplotter]

Good ole AP - I never knew that either. What would we do without you

Blow a sigh of relief probably

[VirginVegGrower]

Not at all - you're most informative!

[eospete]

I understand (from somewhere) that because of the huge surface area of vermiculite due to it being porous that it will not only hold on to water on its surface but also soluble nutrients in that water.
Only from what I have read and can remember you understand.
P

[DuncanM]

A relatively old post now, but thought I'd share anyway.

Vermiculite does retain both moisture and nutrients (to a certain extent). It's useful as it will hold a quantity of water (so good for retaining moisture) but also once that capacity is reached it is useful for drainage.

For the record the cheapest place to buy vermiculite is at a building suppliers (Jewsons). It's about £16 a 100L bag (although I have a discount code for £10 :P ) and it's much, much cheaper than a garden centre (about £10 for 10L).

[chris]

Is it the same as horticultural grade vermiculite though? I'd have thought it'd have been treated/sterilized?

[veggiechicken]

When I had the Aga installed, they filled it (not the ovens-silly) with vermiculite for insulation and heat retention. I asked the fitters for any leftovers for the garden - so they gave me an unopened sack of the stuff! Its coarser than the garden vermiculite - bigger flakes. Maybe the builder's merchants stuff is the same. I have a use for it - whatever the size

[otorongo]

Just be careful not to breathe in the dust, some vermiculite products contain asbestos.

Mix it outside in quiet weather, or moisten it beforehand, or wear a mask...

[FROSTYFRECKLE]

Nicos, can you sift the vermiculite from the potting compost. Chuck potting compost onto your beds, then have a barbie and sterilise your vermiculite. Get an old pan and pop the spent vermiculite in. Barbie your sausages then pop the the old pan onto the barbie. Leave until cool.

[Bigmallly]

Oh good - daft ol' me thought it was just to lighten the potting compost to allow better drainage!

That's perlite Nic.