Garden clean-up, the last big chore for gardeners, is often overlooked, especially if it's been a strenuous gardening year. A gardener can overwinter plants by putting them in a cellar or a cool, sheltered location. Even without heating, a conservatory providing a minimum of 5-7C (41-45F) makes an ideal place to overwinter tender plants from the garden.

Overwintering plants, need to be well supplied with moisture to withstand desiccation conditions brought on by winter winds and frozen soils. Place overwintering plants and rooted cuttings in as much natural light as possible. Heated greenhouses with roll-up sides are an option for overwintering plants above freezing, and is successfully being used by many growers. But a gardener does not need to have a greenhouse in order to create the ideal spot for overwintering plants. Just as farmers have done for millennia, try saving seed from some of your most successful overwintering plants. If you have limited space for overwintering plants, make it a priority to save those which are expensive to buy, as well as anything unusual that might be difficult to find the following spring. Built a shelving unit, with some adjustable shelves on it, and a grow light attached to the bottom of each shelf.  

Overwintering means maintaining the minimum temperature needed for plants to survive, sometimes it requires heating even if it is for a short period of time. The key to overwintering is to maintain even temperature, keeping the plants cold and alive but not actively growing. Unlike field grown plants, container-grown plants cannot take advantage of the temperature buffering effect of the soil.  One of the simplest techniques growers have been using to keep plants at a constant temperature below freezing is placing a sheet of insulating material over containerized plants during the coldest months of winter. Under average conditions, temperatures within these structures do not reach levels that result in injury to plants that are stored inside.