It is important to heed the warning when your local forecaster announces 'a chance of frost', and take precautions to protect your garden. It is possible to extend your growing season by several weeks if you are able to keep your plants alive through a single early frost.
The best way to avoid frost damage is to grow plants that can withstand the frost. The term 'frost hardy' is often misleading because of the degree of frost (i.e. light frost vs. hard killing frost). It is a good idea to ask us what is suitable to grow in your area. Even better, look around your own neighborhood, and see what survives and thrives in other gardens.
Because cold air, being denser than warm air sinks, low-lying areas of the garden can be several degrees colder. Consequently frost may occur in these areas when there is no frost evident anywhere else in the garden. Plant tender species on higher ground or on slopes where the cold air will flow past the plants as it moves to the low point. Any sloping area is less prone to frost, because the cold air can't settle there as easily. Precondition your plants to withstand cold temperatures by discontinuing fertilising in early March, so that no new foliage is on the plant when cold temperatures arrive. Older leaves are much tougher and more able to withstand a frost.
When The Inevitable Occurs And A Frost Is Predicted, There Are Several Things That You Can Do To Protect Your Plants.
Hardening off plants is perhaps the most efficient way of getting your garden and potted plants through the winter. The best way of hardening your plants is reducing the amount of water the plants receive in autumn and reducing this further as the season develops. This will cause all the new growth to harden up giving it natural protection.
Using your natural surroundings is also a good cheap option. A few good ideas include moving any pot plants under the eaves of the house or to plant tender plants next to brick or block walls. This is because they release heat overnight increasing the ambient temperature around the plants.
Cover up your plants before dusk. By the time it gets dark much of the stored heat in the garden has already been lost. If you have time, build a simple frame around the plant, or row of plants. (Even a single stake can be used in many cases.) Then drape a cover of frost cloth, newspaper, cardboard, plastic tarps, bed sheeting or any other lightweight material over the frame to create a tent. If you don't have time to create a frame, lay the protective cover directly onto the plant. This will help to slow the loss of heat rising from the foliage and the ground. Remove the covers in the morning, once the frost has thawed, to let the light and fresh air back in, and to prevent overheating by the sun.
If your efforts were too late, or too little to protect your plants from a frost, resist the urge to cut off the damaged parts of the plants. To a certain extent, these dead leaves and stems will provide limited insulation from further frost damage. You will have to go back and re prune your plants in late spring when the frosts are over.