Ways to weatherproof fabric?

[minta]

I have NO idea where this question belongs! I want to spray a sofa with something to make it mildew-resistant so I can put it on an open-air porch. I have 1) no clue what to use and 2) no clue whether or not any of the available products are safe for my family (I have 2 babies who will suck the fabric, I'm sure, plus a cat) and I want to make sure whatever I get doesn't up the flammability (is that a word?). Any suggestions? TIA!

[swiss.army.mom]

To clarify:
Do you want to make the surface of the couch resistant to mildew, or do you want to waterproof the whole couch (make it impermeable to water and humidity)?

If it's the first, I don't think it will be a long-term solution, b/c humidity will eventually grow mildew beneath the surface (unless you live in the arid southwest maybe)

The only way to keep the inside of the couch from growing mildew eventually would be to do the latter -- fully vapor and water proof it. I can't imagine (besides beeswax) what natural (non-harmful) product would do that.

[janasmama]

check out nikwax or tectron. nikwax is non-toxic but I'm not sure about tectron.