The ready or started part is fine. The ability to raise bread without adding commercial yeast will be longer though.I have a starter recipe I can give you mine was ready to use in like 3 weeks
although Ron will say it takes to long
Sour Dough Starter from Scratch
Ingredients
1/2 cup plain yogurt
1/2 cup milk ( skim, regular or buttermilk) 1/2 cup unbleached flour
Directions
1. Mix the milk and yogurt together in a glass or pottery container (Do not use metal).
2. Place lid on it, but don't seal it (sealed starters have been known to explode).
3. Put mixture in a warm place (80 to 90 degrees) for about 24 hours.
4. The yogurt and milk will separate forming a large curd, when adding the flour just stir it all back together.
5. Add the flour stir, and put back in warm place for 3 to 5 days; stirring daily.
6. It will bubble and have the odor of fermentation it is ready to use.
7. Remember the starter is a living thing and needs to be fed and fed frequently when an infant.
8. I feed the "infant" weekly by placing it on the counter for several hours and allowing it to come to room temperature.
9. Then remove 1/2 cup starter, discarding the remainder.
10. Feed the 1/2 cup with equal amounts of milk (buttermilk will produce a stronger sour taste) and unbleached flour; i.e. 1 cup flour and 1 cup milk plus 1/2 cup of starter.
11. If you would like, you can feed the starter with 1/3 cup dry milk powder and 2/3 cup bottled water in place of the 1 cup milk.
The fastest way to get starter that is active is to get some from someone like me or penny! That will be ready in days
My grandma made the best corned beef & cabbage. It was very colorful too. Pink meat, still slightly green cabbage, big hunks of potato & vibrant orange carrots. I don’t know how she did it. I’m assuming she steamed it or used the crock pot. 
