I moved from a low humidity area in October 2013 to a high humidity area (Northern CA to South Carolina.) In CA I used to straighten my wavy hair all the time. But when I got here I quickly realized there was not much point in doing that. I'd waste a lot of time in the mornings only to have it frizz right up when the humidity got high.
I'd also been using all natural shampoos and conditioners from Trader Joes for years. But alas, no TJ here in my area. So when I ran out I went to Publix and bought the crappy drugstore brand and within a week my hair felt awful. Then I remembered the whole No Poo thing I'd read about years before on Naturallycurly.com. So I decided to give it a try again.
Here's a great description of the idea, why it works, and how to troubleshoot issues: http://coderedhat.com/no-poo-method/
I'll just give you my personal experience too. My scalp doesn't get oily until at least 3-4 days after using traditional shampoo. So I can have good looking second day hair, brush it really well at night before bed (when I've straightened it) and again in the morning and it's still fine on day 3. Day 4 usually requires a ponytail. My scalp is drier than the desert though and gets itchy as hell. I have battled this for 25 years. No matter what dry scalp/moisturizing/dandruff/eczema shampoo I tried, nothing worked. My hair gets dry too. So when I first started I was washing with baking soda. Didn't work for me. My hands would be ridiculously dry for days after washing my hair with BS (baking soda) so if it does that to my hands, what's it doing to my scalp? The itch was gone though. GONE completely in the first two weeks. So I think BS works better for people with an oilier scalp.
So now I wash my hair every 3-4 days with either 1/4 C of aloe vera and 2 tbsp of honey, or a mixture of coconut milk and aloe vera from this recipe: http://almostexactlyblog.wordpress.com/2013/06/07/ph-balanced-no-poo-shampoo/ Then once every two weeks or so my scalp starts to feel itchy, like it needs a good scrubbing, so I use a baking soda paste. But that's it, only once every two weeks. And the healthier my scalp gets the longer I'll go between washes.
I love that these things are all natural and totally free of chemicals, and pretty cheap as well. My scalp is clean, doesn't smell weird, and much much healthier. I have a LOT less frizz too. When I was using traditional shampoo and conditioner I would let my hair air dry and then use a flat iron or my InStyler. I would never consider leaving the house without smoothing it down. It looked too awful to show in public. Now it looks a ton smoother. I still wouldn't love to go out without using the InStyler but I wouldn't feel like a frizz ball if I had to. But I've also realized the futility of straightening wavy hair in humid climates so I see a lot less of that in my future anyway.
Now for the conditioner part: You mix a cup of water with a tablespoon of apple cider vinegar (ACV) in a spray bottle and keep it in the shower. After you wash your hair with your chosen method, spray the length of your hair with the GODAWFUL SMELLING ACV mixture. Let's not beat around the bush and downplay this part, ok? It stinks to high heaven. Makes me gag half the time. And if you need more conditioning you use a higher ratio of ACV to water. Leave it on a minute or two, then rinse.
Now the good news is that once you get out of the shower the smell dissipates by at least 75%. Once your hair is dry it's gone altogether. But you'll get whiffs of it while you're drying your hair. Not as bad but it's still there. It's nasty, sorry.
This works really well for most people but I could NOT get a comb through my hair either in the shower while the ACV was in it, or after I got out. It felt horribly tangled and icky to the touch. I hung in there for about two months of this hoping it would get better but it never did. So I finally bailed and bought an all natural conditioner, this one. https://www.sheamoisture.com/Coconut-Hibiscus-Curl-Shine-Conditioner_p_214.html
The first day that I used it I almost wept with joy at the feeling of the conditioner squishing through my fingers. I could comb my hair for the first time without yanking it out at the roots! So I guess I'm now considered Low Poo instead of No Poo. And I'm ok with that.