8 tricks to protect your garden from frost

Hardy evergreens are immune from damage, but frost — which is basically frozen dew — can damage the tender young growth of even hardy plants, and it can kill plants with tropical temperaments. Here are eight tricks to provide a little protection from extreme weather changes.

Depending on your climate, frost can form on your plants from fall to spring. A true freeze, in which temperatures fall below –3°C for more than a few hours, is much more damaging to plants than a light frost.

• Signs of frost or freeze damage include puckered, distorted or blackened foliage and blooms.

Alternate freezing and thawing harms plants just as much as the cold itself. Woody stems may split and roots can heave out of the soil in a cycle of frost and defrost.

• The best defense for hardy plants is mulch.
• After cold weather arrives, spread eight centimetres of shredded bark, leaves or straw to help the soil maintain a constant temperature.
• Cover with netting, chicken wire or tree branches to protect against wind.

When a light frost threatens your small plants, grab a bunch of plastic produce bags.

• Slip a bag over each plant and anchor the edges with small rocks.
• You can also use upside-down flowerpots or cardboard boxes. These covers will deprive plants of light, which does no harm for short periods of less than three days.
• Or, drape an old blanket over the plants before nightfall to trap soil heat and protect against light to moderate frosts. A thick quilt or comforter provides even more protection.

When the first frost is on the way, pull up your tomato plants, shake off the dirt and hang them upside down from your garage rafters.

• The fruits will continue to ripen for several weeks.

Protect wall-trained vines, shrubs and trees with a removable shade.

• To a piece of wood mounted at the top of the wall, attach a sheet of canvas large enough to cover the plants completely.
• Let the cloth hang down over the plants in very cold weather.
• Pull up the shade when it's warm and lower it in late afternoon to conserve heat for the night ahead.

Let a sprinkler play over tender plants all night when a sudden freeze is predicted.

• Water gives off heat as it turns to ice and will keep the plants warmer than the air.
• This trick is often used to keep the blossoms on fruit trees from being ruined by late freezes.

Keep beds moist and free of weeds to head off frost damage in spring and fall.

• Soak beds in the daytime if frost is expected at night.
• This treatment helps heat rise from the soil on chilly nights and warm the plants.

Wrap marginally hardy shrubs in insulated burlap screens.

• First, loosely stack oak leaves or straw around the plant (don't use thin maple or dogwood leaves because they'll become soggy and pack down).
• Corral the insulation in a length of burlap supported by four corner stakes and tie it with cord.
• Leave the top open for air circulation.

Pile mounds of soil 25 to 30 centimetres high around the bases of rose bushes to protect the roots, graft union and lowest buds from cold injury.

Remove the soil in early spring, but wait to prune until the tiny emerging buds indicate the extent of any injury.