On 8/27/2008 6:54 PM, Ed wrote:
We have a lot of planters, containers, and large pots full of annuals. Would
like to re-use the potting mix. Any input would be most appreciated.

Several things can go wrong with reusing potting mix. Nutrients are
depleated by the plants that were growing in it. Its organic components
are further decomposed, changing the nature of the mix. Salts can build
up from both tap water and fertilizers.

When I repot a plant, I might reuse half of the old potting mix and add
fresh mix for the other half. (See my recipe for do-it-yourself potting
mix at http://www.rossde.com/garden/garden_potting_mix.html.)

As mentioned earlier in this thread, the half of the old mix that I
don't reuse I put in my garden. It still has more organic matter than
my adobe clay soil, and any salts will leach away.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/