Providing frost shelter

We’ve written about frost and fruit trees before and noted the importance of providing shelter for some fruit trees in spring, which is the danger time when a heavy frost can damage flowers, tiny fruit, or even drop-bears.

Our resident drop-bear on a freezing cold morning
Our resident drop-bear on a freezing cold morning

So today we want to talk about a few different options for providing that shelter.

The first one is to build a frame over the tree. This is a great option, because you can use the same frame for bird netting, fruit fly netting, or frost cloth, depending on your need and the season.

Frost cloth is a special, fine cloth that keeps the frost from settling on the ground, protecting the trees, vegies or other crops under it. It’s not very tough and is easy to work with – and even sew with, as you can see in the photo below where an industrious Win (one of our Grow Great Fruit Home-study Program members) is sewing the cloth to fit the frame.

Win hard at work at the sewing machine
Win hard at work at the sewing machine

You can avoid the expense of frost cloth by using old sheets. A word of warning if your cover completely covers the tree to the ground – it’s best to put it on when a frost is forecast, and take it off again (or lift it up) mid-morning or when the frost has disappeared.

A bird netting enclosure can be re-purposed to provide frost protection
A bird netting enclosure can be re-purposed to provide frost protection

Another way to provide the protection your trees need is to use assets you already have in the garden. Here’s a photo illustrating how a shed and a couple of tall trees provide a wide frost shadow.

You often won’t notice these micro-climates unless you go looking for them, so next time you have a big frost, check out your garden carefully.

Look all around for the influence of buildings, sheds, fences, water tanks and other physical assets, and also notice how vegetation like trees, grass and vegie patches can determine where the frost lands, and how it flows.

Other things you can do to protect your trees from frost include putting sprinklers on your trees, using frost fans, keep your soil moist, keep the ground cover plants under your trees short and don’t mulch (because it keeps the ground too cool).

Interestingly, all the things we recommend for soil health (like increasing the amount of organic matter in your soil) can also make your plants more resistant to frost.

This is for two reasons:

  1. Plants with a high Brix level have a lower freezing point;
  2. Soil with higher organic matter levels hold more moisture, which makes them less vulnerable to freezing.

Frost is just one of the factors you need to think about when planning your home orchard (our Home Orchard Design short course has 19 different units in it, and frost only accounts for two of them!).

It can definitely make it harder to grow some fruits in a cold climate, but with understanding and planning, it doesn’t have to be a deal breaker.

What are those brown marks on my apples?

We¬†had a great question from one of our Grow Great Fruit members recently about what causes russet on apples, which describes both the yellow marks (as you can see on the side of this Cox’s Orange Pippin apple), and the rough brown marks around the stem end of the apple.

Russet is one of those curious conditions that occurs naturally – in fact several heritage apple varieties include it in their name, like Brownlees Russet, Egremont Russet and Old Somerset Russet. It’s also commonly seen on pear varieties such as Beurre Bosc.

These days, russet is not considered an attractive trait on apples (have you even seen a russeted apple in the supermarket?), and it’s just one of the reasons many of these beautiful old varieties have gone out of favour (which is one of the reasons we’ve planted a new heritage apple orchard to preserve many of these old varieties).

Russet can also be an injury caused by environmental conditions like frost, sunburn, or hail, or by spraying your apples at the wrong time – even using sulphur (which is an organic fungicide we use occasionally) at the wrong time can cause russeting on some apples (as can a lot of the chemicals used by chemical farmers).

This damage-type russet – think of it like scar tissue – usually happens in the three weeks after petal fall, when the trees are flowering, or when the environmental challenge happens. It is often not a problem in itself, but it can make the apples much more vulnerable to other diseases, like various fungal rots, cracking, or even sunburn.

Heritage varieties that were bred in the UK, such as the divine Cox’s Orange Pippin apples (above) or the much-loved Bramley (below), are really not suited to the harsh and hot conditions in Australia, and so it’s very common to see this type of damage on your apples.

Of course once you realise that, you can set about creating micro-climates that these trees will prefer, and you may find that much of the damage is preventable.

You can find out more about creating micro-climates in your garden in Permaculture in Action.

Netting options for backyard fruit trees

Fruit damage from birds, bats and possums is high on the list of complaints from home fruit growers. This week we look at various netting options,and how they can protect your crop from most of these problems.

The birds left us the stems!

Our new cherry trees are now producing fruit (hooray), and even though we drape netted some of them, it wasn’t completely successful – partly because we were a bit late getting some of the nets on, and partly because the type of birds that were giving us a hard time (parrots) are also particularly clever at getting under drape nets!

So, successful netting is not just about doing it in a timely fashion, it’s also about having the right system for your situation.

Another big advantage of netting your trees is providing some protection against hail, and if you’ve experienced hail before, you’ll know what we’re talking about! Hail storms are a pretty common occurrence on the farm and we lose at least some fruit to hail most seasons.

This is what hail damage looked like on our apricots last year:

Hail damage on apricots

Birds not only damage the fruit, but can help spread brown rot as well. There are lots of different ways to try to scare birds away, such as CDs hanging in the tree, fake predators and the like, but the only real solution is to net your trees – the sooner we all resign ourselves to this necessity, the happier we’ll all be!

This simple net below is made with a frame of star pickets and pipe, and is the easiest and most effective solution we’ve seen (and used).

It’s easy to put up (and take down again if you choose), and easy to peg down around the perimeter to stop persistent smaller birds getting in under the net, which can happen with drape netting (as we saw this year!). This particular set up also has wire netting around the base, which can be useful for stopping larger animals from getting into the enclosure.

Drape netting is easier if you are doing a lot more trees, and is very effective against big birds, and can also deter fruit bats, both of which descend on the tree from above and don’t like to get in under net.

Unless you are really diligent about tying off the net around the trunk, it won’t stop smaller birds like parrots, which are happy to nip under the edges of the net and help themselves. Having said that, it does keep the damage to minimum and is definitely worthwhile.

Learn practical strategies that actually work to protect your fruit from birds and other critters in Protect Fruit from Pesky Pests.