We find that Stevia will grow in almost any climate, if it is given the correct soil, fertilizer, and light conditions. Stevia is not frost hardy and must be planted each year. In areas where there is no frost, Stevia is still replanted each year, due to the poor growth of the 2nd year root system.
Stevia should be planted in the spring after the soil temperature reaches 65 deg F., in full sun and in a light, sandy, open, well drained soil with neutral pH. Use a standard garden fertilized. Do not use a lawn fertilizer or fertilizers with high nitrogen. Adding extra Boron will help keep the Stevioside level high.
Stevia rebaudiana seed is available, but difficult to find for several reasons:
Seed is normally very low germination. However from our work with a research university, we have discovered that if you select the very dark seeds and plant only them your germination should exceed 85%.
Stevia grown from seed may or may not be sweet. Usually only universities grow Stevia from seed – looking for that one in a million plants that have more Stevioside than the plants we sell.
Once you find Stevia plants with high levels of Stevioside, it is best to propagate them from cuttings or tissue culture. Herbal Advantage, Inc. is currently working with farmers in the USA, Europe, and Russia to produce Stevia on large scale farms.
Stevia leaves should be harvested in the fall. The leaves contain about 12% Stevioside (one of the sweet factors). The old brown Stevia leaves will contain 8 to 10% Stevioside. The stems contain about 3% Stevioside. The leaves should be harvested early in the morning and dried in the full sun. When crispy dry, store in a plastic bag. Break the leaf with your hands or put them a blender to make powder. We have 2 Stevia cook books in stock.