Plant based skin care starts with extraction.

So you already know that you want to use plants in your products, just like the big skin care companies. The big question is how do you get the goodies from the plants into a cream or serum?
You need to extract your plants into something and there are several methods you can use without needing any special equipment. You'll need your plant material (herbs, barks, roots, leaves etc) in dried form. Don't worry, drying the plants just means the water is gone, not the properties you are looking to extract. The plants need to be macerated (chopped up) for the best results.

1. Oil... You can extract into an oil base and getting the plants in there is super easy. Let's say you are using almond oil. You need a big glass jar, your oil (make sure it's fresh, shelf life is about a year for most oils) and your dried plant material. All you need to do is combine the oil and plants in the jar, mark it with the date and the amount of oil and plant you used. As a rule of thumb, you want the plants to be loosely packed and the oil to just cover them.
Leave the jar in a dark cool place for at least 2 weeks. You can also agitate the jar daily to help the process along. After the 2 weeks just strain out the oil into a new clean jar and you have created an herbal oil that filled with all the goodness of your plants.
2. Water... so basically you are making a tea with your plants (also known as decoctions or herbal infusion). Once again you'll be using dried plants (that's what tea is after all) and combining them with hot water. Be aware that not all water is the same. Tap water is NOT recommended because it's full of impurities that you don't want in your finished product. Get distilled water in a big jug from the pharmacy. Put your plants into a clean dry stainless steel pot on the stove and heat your water in another clean pot. Bring the water to a boil and then pour over the plants. Cover the pot and let it sit until cool. Making an infusion this way can give you a very strong "tea" and depending on the plants you use it can be quite dark in color. This is something to keep in mind for your finished product.
Basically, if you are using tender plants like garden herbs, less time is needed, but if you are using bark or roots, anything that is dense the extraction will take longer.
Please beware! Water extractions must be preserved or they will go bad very quickly. If you are making this bit in advance, keep it in the fridge until you are ready to add it to a product.
3. Alcohol... Yes you can extract into alcohol and you end up with a powerful herbal extraction that's also called a tincture. While this is great for an oral delivery system, we probably don't want to put alcohol on our skin!
If I am making something where I want a strong infusion from the plants, I will used both oil and water to make my product. Lots of plants are not made into essential oils and these methods allow you to make home-made extractions. You can make your own essential oils too, but it requires a still. If you are very ambitious, you learn how to here: http://www.wikihow.com/Make-Essential-Oils