Moving Plants Indoors for Winter

Maybe you can help me, pronto. It's supposed to freeze tonight – I potted a stevia, a bai zhi, parsley, and a few other things. Can they be brought into a garage, then later moved into the house for the winter? Or do they need the cold for their normal cycle of growth?

As an emergency measure you can certainly move plants into the garage for a short time, just to give them the benefit of the slightly warmer temperature of the enclosed, even if unheated space. By opening the door during above freezing days, you can also accustom the plants to lower light conditions. However, in general this will only save the plants from light frosts, while heavy frosts will lower the temperatures in the garage too much to be safe.
By checking the numbers after the Z (stands for "zone") given opposite the latin name of the plant you can tell if the plant is winter hardy in your area. To find out what zone your area is in, go to our web-site at www.richters.com, go to the Info Centre under the News and Info section. There you can consult whatever zone maps we have been able to find.
We have not done experiments to find out which plants must get some freezing to continue to grow well, but have found by experience that some plants such as chives and tarragon must get about a month of frost if they are not to peter out and die. Most frost hardy plants will do fine if they are just kept cool, say at about 5 to 10 degrees Celsius, for the winter.
Of the plants you mentioned, stevia cannot take frost, bai zhi is frost hardy in zones 5 to 8 and parsley will bolt to seed and then die if it is exposed to frost. If parsley is not exposed to frost it might last all winter, but eventually it will flower and die anyway. For information on any other plants again consult our web-site, but go to the Q&A part in the News & Info section, click on "Search Q&A" then type in the herb you need info on and pick out useful sounding questions. Some good information on culture can also be found in the Commercial section.

Another question, how do I use the stevia? The leaves or roots? We're not diabetic or anything, I just like to try other ways of doing things.

You use the leaves only of stevia. Dry them, then crush them into a powder. One or two leaves take the place of a teaspoon of sugar. For more information on stevia consult the web-page. There are all sorts of hints found there for this plant.