by Wally Richards
WINTER AND FROSTS
In New Zealand, the official winter months are June, July and August.
As a Southern Hemisphere country, these months officially bring the coldest temperatures, shortest days, and snow to the mountains, with July usually being the coldest month.
That may have been so in days gone by but I think it is more likely May, June and July these days, however, one can still expect cold times and late frosts in August and even September in parts of the country.
August is in my mind the start of the spring planting time for hardy plants and tender plants in glasshouses. It is the time when we and our plants notice the increasing daylight hours.
I think we are in for a cold winter this year and reports from gardeners in various parts indicate the same with some cold nights, mild frosts, snow on the ranges.
I know I have my wood supply in and have started using it with a fire in the wood burner most evenings.
Those with wood burners remember that the wood ash from untreated wood, called potash, is great for the garden. Sprinkle it over bare soil around your plants and it helps harden up growth and protects them from the cold and wet soil.
If you don’t have a wood burner with wood ash then use Wallys Fruit and Flower Power which is 55% potash and 45% magnesium.
The magnesium helps keep the foliage green which means that the plants can gain energy from the weaker sun in winter. In practice, that means yellow leaves can still capture some light and produce some energy, but their ability to turn sunlight into sugars is reduced.
Older leaves are usually affected first, and severe deficiency can lead to further decline or leaf death if not corrected. So spread either a small amount of Wallys Fruit and Flower around each month or some Epsom Salts with your potash from the fire place.
Winter brings rain and that causes wet feet for plants including those that have problems with too much water around their roots for extended periods (ponding).
Mulches in winter kill plants as they prevent the water from evaporating as it would do otherwise.
Mulches are great in summer during dry times to conserve moisture and certainly help plants survive droughts, but can kill them in wet times. Remove all mulches away from root zones and if plants that suffer from wet feet are in places where water can pond then do this.
Just out from the root zone dig a trench about a spade depth and width so water can drain into it and evaporate quicker with sun and wind. It can be a few open holes at cardinal points, a half circle trench or a full circle one.
Also spray the foliage each month with Wallys Perfektion which helps plants to prevent and overcome wet weather diseases.
For frost protection you may like to use the new Wallys Spray on Frost Protection.
I remember years ago before frost protection products were available I used to throw a jute sack over the low fence where my passionfruit vine grew and leave it over when ever a frost was likely. It worked a treat.
The heavy fibre made bags are no longer available, unfortunately. Frost cloth can be used instead but not only is it a bit of a hassle to apply and remove each day. There is always the likelihood you miss and damage occurs.
In the past we have suggested spraying foliage with Vaporgard and for the occasional frost down to about minus 3C: it certainly works well within 3 days of application.
But if there is two or more frosts night after night, on the second or third frost damage will occur as the plant has not had enough time to recover from the first frost.
The new Spray on Frost protection works within 24 hours of application and will protect down to about minus 15, night after night for up to one month at which time a maintenance spray needs to be applied.
If you start now with a spray of 50 ml per litre of water over the foliage of your frost tender plants and then one month later at 25 ml per litre, repeated every month till all danger of frosts have past it will work a treat.
Miss a monthly maintenance spray and damage will occur as I found last winter on my banana plants.
The mode of action of spray on frost protection is very interesting:
Its a bit of new science that has discovered how freezing temperatures damage tender plants.
Pseudomonas fluorescens, a species of bacteria, has been the subject of extensive research due to its potential applications in sustainable agriculture. One of the most promising applications of P. fluorescens is its ability to control frost damage in crops.
Pseudomonas fluorescens: A Natural Frost Protector
Pseudomonas fluorescens has been found to significantly reduce frost damage in crops.
Research conducted in Australia and worldwide has reported up to an 99% reduction in frost damage at temperatures as low as -15°C.
This significant reduction in frost damage has led to reported increases in yield ranging from 25-100% for numerous crops across many regions.
Mechanism of Action
The mechanism by which P. fluorescens achieves this remarkable feat is through a process known as ice nucleation activity (INA). Certain strains (not all) of P. fluorescens are known as INA- bacteria,
meaning they lack the genes responsible for the production of ice-nucleating proteins (INPs). These INPs are critical in frost injury as they provide a suitable nucleus for ice formation.
P. fluorescens strain, an INA-bacterium, has been found to have efficient activity at temperatures ranging from -8 to -15°C.
This means that this strain of P. fluorescens can effectively prevent frost damage in crops even at these low temperatures.
Plants in glasshouses can also be damaged by cold and frosts as frost cold cant damage foliage that are near the glass. Wet feet will harm tender plants which can survive the winter as long as the growing medium is kept a little on the dry side… That includes indoor plants as well.
So winter-ready your plants and gardens before damage or losses happen.
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