Stevia plants do not like frost, preferring semi-humid regions with well-draining soil that’s mildly acidic. According to experts, the plant will do adequately in soil with pH of 4 or 5, but to bring out its best, soil pH must be between 6 and 7. Whether it's in a pot or the ground, stevia doesn’t like soil that’s too dry or too soggy. Adding compost helps the plant stay consistently moist.

On average, stevia plants grow to between 12 and 36 inches tall, depending on when they're planted. The tallest plants go into the ground just after winter frost ends. For the best results, cuttings need to be planted about half an inch deep and 18 inches apart, so that they can build a solid root network. If that width isn’t possible, you may be able to get away with 10 to 12 inches. For potted plants, use containers that are at least 12 inches in diameter.

This plant thrives in USDA Plant Hardiness Zones 11 and higher. Zone 11 has a minimum temperature range of 40 to 50 degrees Fahrenheit, where this is no chance of frost. Higher zones have temperatures greater than 65 degrees Fahrenheit, making it nice and warm, the kind of climate stevia plants love. They need between six and eight hours of full sunlight daily to thrive.

Stevia is a low-maintenance plant as long as its soil doesn’t dry out completely or become too muddy. If the former occurs, water the area until the soil dampens. The wilted plant can perk up in as little as a few hours. While it’s a good idea to fertilize your stevia during the summer months, avoid chemical fertilizers because they negatively affect the plant’s sweetness.

Aphids, whiteflies, and cutworms are a few of the pests that can affect your stevia plant in addition to slugs and snails. Thankfully, pungent organic sprays with ingredients such as garlic and rosemary will get rid of many insects, while crushed eggshell around the base of the plant deters the mollusks.

Septoria apiicola or leaf spot blight is caused by a few different fungi, including Alternaria alternata. The stevia leaves develop black spots and eventually fall off, causing the plant to look like a burned-off stalk. Then there's the more recently discovered stem and rot disease, also known as white mold, caused by the Athelia rolfsii fungus. Both diseases can live in the soil for years before infecting plants. They can stunt plant growth and lead to brown lesions that develop into necrosis, killing the plant altogether.

Stevia doesn’t require any special nutrients, making it a relatively frustration-free plant. For those with a potted stevia plant in cooler climates below 40 degrees Fahrenheit, know that during winter, the plant is less active and won’t need as much watering. Additionally, consider using fluorescent lights if your plant is unable to get at least six hours of natural sun.

It’s a good idea to propagate your plant because mature plants lose their potency after two years. When dealing with an established plant, cuttings need to be about six or eight inches long. Remove the leaves close to the bottom of the cutting. For faster rooting, consider dipping the bottom in a natural rooting hormone made with auxins. Plant the cuttings and keep the soil moist. In about 30 days, the cuttings should have enough roots to be transplanted to their permanent beds.

During midsummer, before it flowers, pinch off the leaves of your stevia plant. While you can use the fresh, crushed leaves in your favorite tea, you may want to have some ready for later in the year. To dry the leaves, place them in a paper bag or a drying rack and store them in a dry, cool area away from direct sun for two or three days. Check them to see if they are dry enough. If they aren’t, keep them for another few days. Once they are ready, store them in an airtight jar. Keep in mind that the longer you keep them, the less potent they will be.