Larry Smith and the Riverside Gardens team talk all things pots, plants and pruning in their weekly gardening column.
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One week into winter and we have nearly had a bit of everything it has to offer weather wise.
Dreary cloudy days, bleak misty days, rainy days, and foggy days, but none of my favourite winter weather — cold, dead still frosty mornings followed by beautiful sunny days.
I know a lot of you will be thinking what about all the damage frosts can cause but hey, those sunny days that follow a frosty morning are some of the best, and with a little care, the damage caused can be minimised.
In our neck of the woods, we are affected by what is known as radiation frosts, which are a lot easier to deal with than those frosts caused by icy cold winds.
Radiation frosts occur on cold still nights when there is little or no cloud cover to act as a blanket to trap in the warmth of the day.
After the sun goes down, the ground loses its heat directly into the atmosphere and the surface temperatures start to chill rapidly.
If a dew has settled on the plant’s foliage, it starts to freeze on the surfaces where it lays, and can cause damage to plant cells beneath.
This damage is caused by the fluid within the cells freezing as the frost cools the plant down quickly.
With the prospect of frosty mornings in the coming weeks, it is time to make sure your garden is in the best position to handle them.
That way you will be able to enjoy those beautiful sunny days that follow without too much of a worry.
So here are a few simple steps you can take to help protect your plants and give you that peace of mind.
Plants that are stressed for water are a lot more susceptible to frost damage, so ensure you keep the water up to them.
Remember, though, that without the drying winds and hot days they will require a lot less water to keep them happy.
Moist soil also retains its heat much better than dry soil giving your plants a better heat bank.
Organic mulches also help retain heat in the soil particularly mulches like sugar cane that will generate a small amount of heat as they break down.
Be mindful of the type and timing of applying fertiliser. High nitrogen fertiliser that promotes a lot of soft new growth should be avoided coming into and during winter.
Higher potassium fertilisers will encourage stronger fuller cells with a higher concentration of starches making them less likely to freeze.
Potassium also assists in the opening and closing of the stomata cells, the tiny pores on the leaves that transfer gases in and out of the leaf.
This prevents water loss and protects leaves from wilting and becoming more prone to frost damage.
Frost covers made from a breathable material are probably the most common forms of frost protection for the home garden.
Commercial frost cloths are the best of these as they are light weight, semi translucent, and dry out quickly between uses.
We stock a 2-metre-wide bulk roll in the Garden Centre which is sold by the metre.
This is the same cloth that we use over the most frost tender plants in the nursery.
Old bed sheets, or bits of hessian are an alternative you can use to thrown over your most frost sensitive plants and they too will work fine.
The main thing is to remember to put them out on nights of predicted frost and to remove them again the next morning.
Antitranspirant sprays such as ‘Envy’ have been sold and used for frost protection extensively throughout the industry in recent years.
These sprays are used to reduce transpiration in plants, that is the natural water loss through the foliage.
It works by putting a semi-permeable, biodegradable protective film over the leaves and stems making them more drought tolerant and less susceptible to sun scorch.
It can also increase the plants frost tolerance by about an additional 4℃.
This works particularly well on susceptible trees like jacarandas until they are mature enough to fend for themselves.
In the Garden Centre, we mainly use our irrigation system for frost control.
The banks of sprinklers come on in constant progression over the plant area throughout the early hours of the morning when frosty conditions are predicted.
This method works well as long as the leaf is regularly wet down while the conditions exist.
It works on the principle that the water partially thaws the frost before freezing and releasing heat energy as it does.
It is quite stunning to see the results in the morning with little frozen stalactites hanging off everything glistening in the sun.
We implement a combination of all these methods within the Garden Centre depending on just how frost sensitive certain plants are.
By doing this, we manage to get through most winters with very minimal damage to the plants.
That’s probably why I don’t mind those frosty mornings with the crisp air and beautiful sunny days.
Remember, if you do get frost damage on some of your plants, resist the temptation to prune it off until after the frosty season has finished.
That way it will act as a protective barrier to the foliage underneath.