Frost - what is it and how to manage it
Jul 16 2018 2 Comments Tags: climate, frost, winter
I know our winters aren't really cold by any means, we don't get snow, in fact, we are more likely to have a beautiful sunny day after a frost, and can have a temperature increase of over 20 degC in one day! But this actually makes things trickier because we can ALMOST grow tropical plants, but it only takes one hard frost to knock them back until the weather warms up in spring. Fortunately there are a few tricks we can use to manage frost when we understand what it is and how it behaves.
frost on broccoli leaves |
The important point is that we can expect cold temperatures to develop on clear still nights, but that if we understand how cold air moves and how frost forms from moisture in the air, we can take steps to prevent frost damage.
silverbeet with frosted leaves |
- Plant appropriate varieties and understand which vegetables are going to survive and which will need extra protection or if they are just bad choices for your location.
- Protect sensitive vegetables by planting under under cover of trees, close to water tanks or the house (which holds a little heat overnight and can prevent the temperature falling below freezing) or plant in pots that can be moved to safer ground.
- Even though this sounds bizarre, if you water at night before a frost is likely, wet soil will hold more heat and may maintain temperature above freezing (although this can backfire if it does get cold enough to freeze the water on the ground and on leaves).
- If you can circulate the air above your garden using a fan (or a helicopter or a million butterflies) you can mix the cold air near the ground with warmer air higher up - this is used in commercial orchards.
- Cover your veges with fabric or straw/old leaves to try to maintain the air temperature around them. I keep reading to not use plastic, but personally I have had success with using clear plastic all around the plant, and including a bucket of water so the air under the tent is more humid, as this maintains a warmer temperature around the plants.
- Consider where cold air will flow and make sure if can't get trapped uphill of solid fences or hedges in your garden, and also use this concept to direct air AROUND plants but stacking hay bales etc uphill of a sensitive plant.
frozen sprinkler... |
Bella helping to trim the frost-sensitive arrowroot |
- I planted frost tolerant veges so I have something growing in the garden - this includes brassicas, peas, broadbeans, silverbeet, leeks and spring onions, and I won't get so upset when the beans and tomatoes die :)
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plenty of frost-tolerant brassicas and asian greens this winter :) |
- I bought a small greenhouse for the sensitive plants that I want to keep - chillies, eggplant and avocado that took SO long to mature, I don't want to start from scratch next spring, so I hope to keep them all alive over winter, I also put away the greek basil and the ginger. We were planning to have the aquaponics greenhouse finished, but got carried away with other projects, so a $40 plastic greenhouse is sufficient to keep a few things safe from frost this winter.
- I cut back the frost sensitive perinnials - the beans, arrowroot and comfrey all die back from the frost, so I thought I may as well cut them back while they were green and use them for mulch before they die. This also reduced the shade around the garden (great for summer but unnecessary in winter). In the end I didn't get to use any of it for mulch as Bella and Molly decided to eat it all and I didn't mind. I didn't have the heart to cut back the giant paw paws though!
- Keep sprouting - even in the middle of winter if you can't get anything to grow outside, you can always sprout! Over summer I used lots of sprouts in salads, and in winter I like to grow the larger sprouts (mung beans and fenugreek in particular) to throw into stews and steamed veges.
- Changed watering routine - instead of watering in the afternoon after work using the hose with spray nozzle, I have rigged up a large sprinkler so I can water first thing in the morning, this means the plants won't have soaking wet leaves overnight, which can cause extra frost damage. Early morning water can also help to warm up frosted leaves before the sun hits them and causes them to heat too quickly.
- It does kill off a number of annoying weeds and bugs
- At least I can grow veges that do like some chill time, like carrots, turnips, swedes and broadbeans, and fruit trees like apples and stonefruit (or at least I hope I can grow them!).
Do you have frost? How do you manage it?
2 Comments
Hi Liz, we had our first frost of the winter this week and thankfully it was very light and the only damage I can see is some burnt grass. I’m so glad I found your site and I have spent some time today reading through all your posts. I have so many questions for you but I will keep reading through your site as I will probably find the answers I am seeking if I just keep reading. the only problem is that Im at work and should be doing work but thats so boring and the only thing on my mind atm is working on becoming self sufficient and leaving this job behind. ha ha
I might take a quick look at Instagram first then back to work.
cheers
Louise
yeh we get frost here too; you forgot to mention that citrus love frost, they actually need it , my lemon tree always drops it fruit if it doesn’t get at least one good frost in the year. we had a good frost this morning, everything was pure white
great post
thanx for sharing
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