If you're adamant about doing totally natural conditioning treatments, then you won't have many options since most natural conditioning treatmens are oil-based. I know that aloe vera gel, milk, bananas and honey are supposed to be very moisturizing, so you could try something with them. But others have reported that these things did nothing for them.

Conventional deep conditioning treatments are easy to find and produce good results for most people. Just be sure to check the ingredient list first for items that might trigger your allergies. Oil is death to my skin as well so I avoid it whenever possible. For years, I've been using Pantene conditioning treatments and having great results with them. Most commonly, I use the Deep Fortifying, Strengthening and Moisturizing treatments, but I really recommend any of them.

Salons and beauty supply stores also carry treatments. Many of which are naturally based, but often on the pricy side. Just depends on what you're looking for.
Anyway, best of luck.