How to Measure the Healthiness of a Plant

Inspect the coloration of the leaves. Healthy plant leaves are typically always green because of the chlorophyll they use to turn sunlight into energy. Leaves that are turning brown, yellow or black are unhealthy and could be an indicator of a sick plant. However, some plants have leaves that may be naturally yellow or even have shades of red, like the red-veined prayer plant, so research your particular species to determine the ideal leaf color.

Conduct a soil test with a pH test kit to measure the acidity/alkalinity of the soil. Every type of plant prefers a different pH range, with most preferring neutral soil around 7.0. A pH that is outside the comfort zone for your specific plant could be an indicator of unhealthy conditions. Soil test kits typically have a vial and special powder. Take a sample of your soil and place it in the vial with the powder and some water; shake it around, which makes the water change color. Match the color of the water up with a color sheet that comes with the kit to determine the pH.

Feel the leaves for rigidity and make sure there are no leaves scattered around the base of the plant. Healthy plants should have strong, moist leaves. Leaves that are withered, dry or cracking could be an indication of drafts or a dying plant.

Check for insects like mites and aphids. These little pests often eat away at a plant's foliage and nest in their stems. Aphids are usually white or green; they are smaller than a grain of rice. Mites leave webbing strewn about the plant's stem. Consider using a plant-safe pesticide to remove the pests before they kill your plant and infest any other plants you may have.

Inspect the leaves for fungal or bacterial infections. These could be indicated by the presence of holes, rust-colored stains or black spots on the leaves. Cut away areas of the plant infected by any fungus; apply a fungicide and antibacterial.