In our Sunshine Coast nursery we get one or two days of frost in winter. Enough to make us rug up in extra sweaters in the morning.
But if you live in the hinterlands, ranges, or down in the southern states, you'll know it can get pretty chilly in winter. Here's how to make sure your plants get through the cold in their best condition.
You might be surprised what survives a cold snap in your own garden. Make sure you have free-draining soil if you are growing plants that might be borderline frost-tolerant.
Free-draining means soil that doesn't stay wet and cold after watering - the water moves through it from the surface to the bedrock (or out of the bottom of a plant pot).
If you have plants in pots, adding perlite or vermiculite to the compost makes a lighter airier mix that helps improve the drainage. Water trickles through faster, which means cold winter water is not sitting around the roots. If you have plants in the ground, adding plenty of organic matter - compost and biodegradable material - at planting time, and as seasonal mulches, helps improve soil texture.
This will also do double duty by helping retain moisture during dry hot summer months as well. Reduced watering will help get plants through the winter too, especially for those plants in pots. Give them just enough to keep them ticking over. More plants die from cold wet roots than frozen leaves.
Protect all tubestock plants for the first couple of years until they develop a woodier stem or bigger rootball - just like you would protect a toddler from the cold, until it can run around and keep itself warm!
You can see three different ways of protecting plants from cold weather here:
The upturned terracotta pot trick works for plants that go dormant in winter, but still need their roots protecting. This includes herbaceous plants that die back above ground, and summer-flowering bulbs.
Plants that are still growing will need access to light! There's some very fancy glass cloches around if you've got the bucks, like those above, or this beautiful vintage Edwardian example. The roof removes on this version to allow for ventilation during the day.
This is important when plants are still growing, to avoid fungal diseases like mildew occurring.
If you haven't got the cash for fancy glass cloches - or you'd rather have unbreakable things out in your back yard for safety reasons - sturdy plastic is a sensible alternative. Big bell cloches pop straight over larger plants, which is a fast and easy method of protection.
They have air vents in the top for ventilation, and holes in the rim so you can peg them down in windy weather. Temporary cloches made from cut-down soda or water bottles are ideal free solutions too, to cover smaller-sized plants.
They create a little microclimate around the plants which raises the ambient temperature, and you can remove the lids during the day for ventilation.
It's not just smaller or more tender plants that need protecting. It goes for some larger plants too. Not all nurseries grow their plants outdoors like we do, and plants that move from a warm protected environment to an outdoor one can suffer shock.
A free-standing semi-permanent frame (like this large-size roller-fronted version at Oregon University) will help 'harden off' the plants. This is a gardening term which means gradually helping plants get used to colder temperatures.
If you're handy, and you have the space, you could rig up a large frame like that; or this smaller, simpler, version with a lift-up roof for access and daytime ventilation. Made from panels of clear polycarbonate roofing, it has a cosy lining of insulating bubble-wrap. You can find plans to build these online, if you search for "cold frames".Both enable a greater number of plants to be protected; and the plants themselves provide protection for each other.
The translucent sides mean that light can get in too; and the roofline slopes towards the front, so that snow and ice slide off.
Horticultural fleece - a specialist translucent blanket-like thin fabric - will keep the worst of a night frost off a prized plant.
You might find this sold by the metre in agricultural supply stores as spunbonded fabric. Here's a improvised shelter for vegetable seedlings, made with a bent frame to keep the net away from the leaves.
Half a hula hoop would do the trick to create a speedy frame.In an emergency, throw a net curtain over larger plants, or for smaller plants in a pinch, one of those pop-up picnic food nets.
They'll keep snow off as well as flies! image: Nostepinne
Protect prize bushes with a swaddling of hessian - it's breathable so you don't need to ventilate it during the day.
Wrap it around the growing stems, and secure it to the central trunk, like these rose bushes here.If you have plants in tubs - and they're too large to bring indoors (or you don't have the space for them) - move the pots to the shelter of a north-facing wall during cold spells, or under the eaves. The residual heat from the bricks will help keep the plants warmer, and the wall will provide shelter from chilling winds.
But if you live in the hinterlands, ranges, or down in the southern states, you'll know it can get pretty chilly in winter. Here's how to make sure your plants get through the cold in their best condition.
Help your Plants Out in Winter
Frost tolerant plants will cope with a cold spell better if they are prepared for it. That includes :- a well-established rootball
- a woody trunk or branches
- a free-draining soil
- a sheltered location away from wind
Free Draining Soil
Plants don't read the gardening books, so they don't always know how they are supposed to behave. Even supposedly tender plants like camellias and aloes - or some palm trees like these in a Paris garden - can come through snowfall.You might be surprised what survives a cold snap in your own garden. Make sure you have free-draining soil if you are growing plants that might be borderline frost-tolerant.
Free-draining means soil that doesn't stay wet and cold after watering - the water moves through it from the surface to the bedrock (or out of the bottom of a plant pot).
If you have plants in pots, adding perlite or vermiculite to the compost makes a lighter airier mix that helps improve the drainage. Water trickles through faster, which means cold winter water is not sitting around the roots. If you have plants in the ground, adding plenty of organic matter - compost and biodegradable material - at planting time, and as seasonal mulches, helps improve soil texture. This will also do double duty by helping retain moisture during dry hot summer months as well. Reduced watering will help get plants through the winter too, especially for those plants in pots. Give them just enough to keep them ticking over. More plants die from cold wet roots than frozen leaves.
Ways to Protect Your Plants
Protect all tubestock plants for the first couple of years until they develop a woodier stem or bigger rootball - just like you would protect a toddler from the cold, until it can run around and keep itself warm!
You can see three different ways of protecting plants from cold weather here:
- vintage glass bell cloches
- a little polytunnel - clear plastic sheeting stretched over a rigid frame
- and an upturned terracotta pot.
image: Maggie McCain
The upturned terracotta pot trick works for plants that go dormant in winter, but still need their roots protecting. This includes herbaceous plants that die back above ground, and summer-flowering bulbs.Plants that are still growing will need access to light! There's some very fancy glass cloches around if you've got the bucks, like those above, or this beautiful vintage Edwardian example. The roof removes on this version to allow for ventilation during the day.
This is important when plants are still growing, to avoid fungal diseases like mildew occurring.
image: Smabs Sputzer
If you haven't got the cash for fancy glass cloches - or you'd rather have unbreakable things out in your back yard for safety reasons - sturdy plastic is a sensible alternative. Big bell cloches pop straight over larger plants, which is a fast and easy method of protection. They have air vents in the top for ventilation, and holes in the rim so you can peg them down in windy weather. Temporary cloches made from cut-down soda or water bottles are ideal free solutions too, to cover smaller-sized plants.
They create a little microclimate around the plants which raises the ambient temperature, and you can remove the lids during the day for ventilation.
image: Mandy Prowse
It's not just smaller or more tender plants that need protecting. It goes for some larger plants too. Not all nurseries grow their plants outdoors like we do, and plants that move from a warm protected environment to an outdoor one can suffer shock.
A free-standing semi-permanent frame (like this large-size roller-fronted version at Oregon University) will help 'harden off' the plants. This is a gardening term which means gradually helping plants get used to colder temperatures.image: Oregon State University
If you're handy, and you have the space, you could rig up a large frame like that; or this smaller, simpler, version with a lift-up roof for access and daytime ventilation. Made from panels of clear polycarbonate roofing, it has a cosy lining of insulating bubble-wrap. You can find plans to build these online, if you search for "cold frames".Both enable a greater number of plants to be protected; and the plants themselves provide protection for each other. The translucent sides mean that light can get in too; and the roofline slopes towards the front, so that snow and ice slide off.
image: Derek Gibbons
Horticultural fleece - a specialist translucent blanket-like thin fabric - will keep the worst of a night frost off a prized plant. You might find this sold by the metre in agricultural supply stores as spunbonded fabric. Here's a improvised shelter for vegetable seedlings, made with a bent frame to keep the net away from the leaves.
Half a hula hoop would do the trick to create a speedy frame.In an emergency, throw a net curtain over larger plants, or for smaller plants in a pinch, one of those pop-up picnic food nets.
They'll keep snow off as well as flies! image: Nostepinne
Protect prize bushes with a swaddling of hessian - it's breathable so you don't need to ventilate it during the day. Wrap it around the growing stems, and secure it to the central trunk, like these rose bushes here.If you have plants in tubs - and they're too large to bring indoors (or you don't have the space for them) - move the pots to the shelter of a north-facing wall during cold spells, or under the eaves. The residual heat from the bricks will help keep the plants warmer, and the wall will provide shelter from chilling winds.
