This is my current sourdough starter.
These types of old world skills are a dying art, and it breaks my heart to see them go. I share with you all in hopes of inspiring you to give it a go, too.
I will be growing a new sourdough starter beginning October 1st. If you're interested in growing your own along with me, I will post daily updates for you to follow along with.
You will need a glass quart jar or similar sized glass container with a lid.
A clean towel, cloth napkin, or other cloth of a size that will adequately cover the opening of your jar or container. Even a clean bandana will do!
A rubber band large enough to secure your towel to your jar or container.
A bag of flour. You can use any flour available to you, but it is my experience higher quality flour grows stronger yeast, so maybe spring for the $5 or $7 bag of flour. I will be growing a rye starter, but the steps will be the same for wheat, so you do you.
Water. You will need spring water, distilled water, or carbon filtered water. Tap water will contain chlorine or chloramine which will prevent yeast from growing.
A small kitchen scale. This is not such a necessity you won't be able to grow a starter, but it would be best. Use one, don't use one. It won't ruin your starter if you don't.
Patience. It will take a minimum of a week, but likely two weeks before your starter is performing well enough you can start baking bread with it.