Adding chopped cabbage to boiling water helps to release the anthocyanin.

II took the outer leaves from two red cabbages, chopped them up into some boiling water, and let them sit for about 10 minutes. I then strained the water from the cabbage into a mason jar, producing a lovely, dark purple solution. I was a little skeptical that anything could happen, but lo and behold, it did!


Straining the juice from red cabbage leaves.

I had so much fun testing the cabbage juice and making testing strips. When various ingredients were added, the results were quick and colorful. Chemistry has always amazed me. I sometimes wish I would have followed that path, I do so enjoy a good science experiment.

If the cabbage solution turns red, the pH is less than 3, which is very acidic. This was the case with the ascorbic acid (vitamin c) and vinegar. Violet means there is a pH of 4-7, like with our tap water, the cabbage juice solution, dish soap, and my spit. Yes, my spit. Apparently, when using the homemade test strips, healthy, normal spit should not change the color of the strips unless you have just been eating pizza or drinking (like my test subjects were). Blue, my favorite color, ranges between a pH of 7-8. Since 8 is my favorite number, it makes it easier to remember, for me anyway. Baking soda is blue, which is slightly alkaline.


Red cabbage juice (center) reveals pH levels by changing color vibrantly when different ingredients are added.

Now the lye, which is extremely alkaline, did some surprising things. I mean, the whole color changing thing is just totally amazing to begin with. Seeing such a dark solution turn red and blue is fun, like coloring eggs at Easter. The lye first turned a dark forest green, then over the course of a full minute kept getting lighter and lighter until it turned a bright yellow! The whole experience was worth it just to see that! I felt like a kid again, and I definitely recommend anyone and everyone to try the red cabbage indicator experiment with all the proper precautions and adult supervision.


Homemade coffee filter test strips change varying colors from acidic to alkaline.

Using all of this information in regards to hydroponics depends on what you are growing. For the plants I am planning on growing (tomatoes, cucumbers, peppers, etc.), a 6-6.5pH is recommended. That means my growing solution would need to be more towards a slight reddish purple. Testing the pH is going to be an everyday occurrence, so it is definitely something I want to have a deep understanding of.