Substitute For Vermiculite

[shingman3]

Can anyone tell me what would be a good substitute for vermiculite? I want to make a square foot garden this year and this was supposed to go into mix with peatmoss and compost. Too expensive and hard to find large quantities.

[David Marek]

Are you near rice growing areas? I used an experimental potting soil which used rice hulls to replace perlite and vermiculite (and lower the cost), with good results. Very strong, healthy root systems. It is organic material, so will need to be added periodically, but like the compost I'll bet it supplies some good nutrients as it breaks down. I have not used them as a soil amendment outside, so I don't know if they need to be composted first.

[shingman3]

Thanks For Reply! I don,t live near a place that has that. Thanks!

[dice]

perlite
pumice
crushed lava
bark fines
turface
rice hulls

These would be some alternative products to look for.
(I doubt that turface would be cheaper than vermiculite,
but it should last a long time.) Over time, bark fines and
crushed lava (small size red or black lava) may change
the pH of your beds.

There is still a rice grower over in Darlington, SC, by the way.
I do not know if they have mountains of rice hulls that people
can load up for free. Bark fines are simply pine or fir bark in
fairly small pieces (screened to remove big chunks).

The idea of vermiculite is to provide something with a larger
particle structure than most sand (to add air spaces to the
soil and improve drainage) that still holds a little water. You
could check local landscape materials suppliers to see if they
have pumice, but unless you have a nearby volcano, I doubt
that this will be cheaper than vermiculite.

Your best prices on bagged products will probably be perlite
or bark fines.

(I see bagged gypsum sometimes that has particles about the
right size for this. Adds calcium, too.)