Add 1 tsp. of liquid food coloring to 1 cup of water. Drizzle the colored water onto the soil surrounding the base of a plant. Wait 24 hours for the water to absorb. Apply another identical dose if the color change was not sufficient.
Vertical garden. Would love this- if they took care of themselves. I have all this knowledge of plant physiology, and soil science, and fertilizers....but I can't keep any plant alive very long. That's my sister's job. She has the green thumb!