All natural flea repellant

Here in North America our Winter is in full swing.  So this post isn't exactly timely, but we have a question for all of you.  When Spring arrives, what do you use for flea and tick prevention?  We are looking to go the all natural route, as we want to avoid pesticides.  There are so many different suggestions online, we wondered what have you found to be the safest and most effective?

I know many people use the leading topical flea treatments, and they are happy with the results.  And I'm not criticizing those that do choose to use these products.  But after going through the heartbreak of losing a dog to cancer, when he was only 7 years old, we have become very particular about which foods, treats, vaccines and medicines we give our dogs.  Losing a dog is devastating enough, without losing them before their time.  With collies having issues with so many drugs, we already have to be super vigilant anyway.  (See Here and Here). #overprotectivedogmom

Thanks!

And two bloggers already kindly responded to my inquires, but I lost the links to your responses.  Sorry, I didn't want you think I was ignoring your suggestions.

Edit to add:
Our friends at Keep the Tail Wagging just posted about what works for her.  You can find it here -
Keepthetailwagging