Preservatives for your plants..?

[vincolo1]

Just an out of the box thought...
Has anyone ever tried or know anyone who has tried adding food grade Preservatives to your potting soil. I do not know much about the various types of food grade preservatives, but just wondering......
The prospect of doing this would eventually be longevity in plant shipping and even shelf life provided there was no long lasting harm done to the plant.
I am not talking about topical sprays, but actually adding something to the soil....
Thoughts..?

[turtile]

I use pro mix which is soiless. They sell optional Baterial antifungucide versions to prevent root problems.

[vincolo1]

soil-less for palms? Does your fertilizer mixture have preservatives in it other then those that prevent fungus?

[turtile]

No, its sterile to begin with. They later add the fungucide.