If you’re looking for a natural, non-toxic wood stain , you might want to raid your kitchen. Coffee, tea, vinegar, walnut hulls and even certain berries can be used to stain wood.
One simple way to stain wood is to boil tea leaves in two cups of water until you have a deep tea concentrate. Simply brush the hot tea water onto your wood. Different teas will give you different shades.
Brew some strong coffee and let it cool; then apply with your favorite brush or rag. Let it really soak the wood. It’s okay if the coffee gathers in small puddles on the wood. You’ll get a deeper stain  depending on how long you let the stain sit. Check it ten minutes after application by wiping a section clean of coffee. Not dark enough for you? Let the coffee sit longer.
Black walnut hulls, soaked for several days, create a dark wood stain . Strain the mixture before you use it. Some people prefer to boil the hulls first, and then allow them to steep.
Black raspberries are an effective wood stain when crushed and then rubbed onto wood. Allow the berry pulp to dry on the wood, and then wipe it away. Berry stains will fade in direct sunlight, so this method is better for wood that stays indoors.
Vinegar works as a wood stain when you add a metal object in the mix and let it sit in a glass container for a week. A handful of pennies will produce a beautiful pale Caribbean blue stain. A wad of steel wool will give you a rich reddish hue. A combination of tea and a metal object in vinegar will produce a black stain.
As with any untried stain, start with a piece of scrap wood. Use the same type of wood you’ll be staining, as stains can look dramatically different on different woods. Not only will this allow you to see if you like the stain, but you’ll have the opportunity to apply several coats to see how the shade changes and deepens. Keep track of how many applications it takes to get your desired result.
Keep in mind, too, that stained wood can change with age–often with attractive results, but be prepared to potentially end up with a different look later.
For stains that may be prone to fading, consider using a clear sealant  on top of your stain.
For crafty folks who like to keep it natural, non-toxic wood stains from coffee, tea, vinegar, walnut hulls and berries are a fun, artistic and wholesome way to decorate.