Put your fruit trees to bed before winter

This week, we’re noticing that the leaves are just starting to change colour on some of the fruit trees at our place, so we’re focusing on things you can do in the garden to help your fruit trees get ready for winter.

The farm's starting to get that 'autumn' feel (thanks to Penny Kothe for this beautiful shot)
The farm’s starting to get that ‘autumn’ feel (thanks to Penny Kothe for this beautiful shot)

One of the most important things to think about is nutrition. It might seem a bit counter-intuitive to be feeding the trees just as they’re about to go to sleep for the year, but it’s really just a case of ‘topping up’.

It's never the wrong time to apply compost under your fruit trees
It’s never the wrong time to apply compost under your fruit trees

In fact, your trees have already started the process of storing nutrients in their buds, bark, and roots (that’s why the leaves have started to change colour), and this nutrition is what they will draw on next spring when they wake up and start flowering.

The beautiful yellows, oranges and browns of autumn starting to appear in pear leaves
The beautiful yellows, oranges and browns of autumn starting to appear in pear leaves

Flowering is the first thing most fruit trees do in spring (except apples and pears, which produce leaves first), and this happens before their roots have really started to function very much, so the stored nutrition is absolutely crucial to good flowering, and good flowering is crucial to good fruit set.

Good flowering in spring relies on the tree receiving enough nutrition the previous autumn
Good flowering in spring relies on the tree receiving enough nutrition the previous autumn

In the natural farming system that we follow and teach, we don’t use artificial fertilisers (which can easily cause more harm than good) but instead rely on the natural fertility system of having a diversity of organic matter and nutrients in the soil, and then making sure we have lots of healthy soil microbes present to convert the nutrients into a plant-available form.

When we talk about nutrition, we’re really talking about feeding the microbes, so they can feed our trees.

So, what to give them? Compost is always great, as is well-rotted manure. If you have a worm farm, worm castings or worm juice provide an excellent, and fast, nutrient boost for the microbes.

Hugh with his pet worms - some of the most useful workers on the farm (thanks to Biomi Photo for this beautiful shot)
Hugh with his pet worms – some of the most useful workers on the farm (thanks to Biomi Photo for this shot)

Liquid seaweed and liquid fish are also great (available from garden centres under various brand names), or if you want to save money, make a batch of compost tea (brewed compost) or compost extract (which is just compost soaked in water to make it go further).

And if you want to drill down a bit more into the Natural Fertility System and how to set it up in your garden, spend a little time learning more about the amazing world of microbes in the online short course Soil Biology and the Soil Food Web

Is rain good for fruit?

A lemon covered in raindrops
A lemon covered in raindrops

As a fruit grower, lying in bed listening to rain on the roof can bring up a wide range of emotions, both good and bad. In our typical dry summers most people welcome rain when it comes, so it never seems appropriate for us to express concern about the damage it can do to fruit. However, it hasn’t rained for a while, so this week we reflect on the question – “Is rain good for fruit?”

Like everything in farming, the answer is complicated, and depends on lots of different variables, so let’s break it down a bit.

1. Trees like rain better than irrigation waterup to a point! As a gardener, you’ve probably noticed how “perky” your garden looks just after rain. One of the reasons (apart from the leaves being cleaner) is because the rain carries dissolved nitrogen which is easily absorbed by the plants, giving them a nutritional boost. Too much rain, however, and the soil can become waterlogged, creating anaerobic conditions, which actually stops the plants’ roots being able to take up nitrogen! The other advantages of trees receiving their water from rainfall (rather than irrigation) are that the entire root system gets water (rather than just at the point of water delivery), and if you’ve been keeping your garden on rations due to dry conditions, they just love the opportunity to get their fill of water for a change!

A fungal disease outbreak on an apricot
A fungal disease outbreak on an apricot

2. Rain can trigger fungal disease. One of the biggest pest and disease risks in an organic farm (or garden) is fungal disease, and nearly all fungal diseases are triggered by wet conditions (at the right temperature). In general terms, the more rain, the more fungal disease. This risk is highest at the beginning of the season (i.e., at flowering time in spring), and then gradually decreases as the season progresses. During autumn, if the summer has been generally dry and there is not much fungal disease around, the risk of a new fungal outbreak is relatively low.

Cherries that have cracked in the rain
Cherries that have cracked in the rain

3. Rain can cause physical damage to fruit. This is very specific to the type (and even variety) of fruit. For example cherries are particularly vulnerable to splitting from the rain, and some varieties of apricots also split easily. Hardier fruit like apples and pears, however, rarely experience physical damage from rain.

An apricot with a severe crack caused by rain
An apricot with a severe crack caused by rain

4. “Hard” rain can damage all fruit. Storms that bring rain often also bring hail, and that can be completely devastating to all fruit. Hailstorms are very random and localised, so it”s pretty much the luck of the draw with this one, though if you live in a hail-prone area, netting can definitely be your saviour. All fruit are vulnerable to hail damage, including apples, pears, plums and quinces.

5. Rain is good for the landscape. When you’re trying to grow food in an arid landscape (as we are), the general impact of rain (as long as there’s not too much, or too quickly) is generally FABULOUS! It fills water storages, keeps the bush alive, helps to sustain our farming communities, and helps backyard fruit growers maintain their own food security. We love it….except…. when there’s too much! If rain becomes flooding and the soil becomes saturated for too long, it can lead to ALL sorts of problems! Anaerobic soil conditions, trees dying, waterborne soil disease, nutrient leaching, dams breaking their banks, and the list goes on. We’ve seen it before when the drought broke in 2010/11.

A rainy morning and green grass
A rainy morning and green grass

6. Rain is good for mental health. It’s a generalisation, of course, but very often rain can be a huge relief to farmers and others in the community, especially if it is relieving the pressures of trying to farm in a dry landscape, though as you can probably see from our list, it totally depends on the amount of rain, and the context!

Poppy lapping up a puddle
Poppy lapping up a puddle

Regardless of the timing of rain within the fruit season, it’s important to make sure your soil can act as a big “water storage tank” when it rains. As well as building really healthy soil (which is good for both water storage and drainage in your soil), techniques like swales and keyline (covered in this short course) can make a huge difference to how well your soil will store rainfall.

Dieback and cankers on fruit trees

One of the signs you may have Phytophthora, or root rot disease, is the appearance of these summer cankers on your fruit trees.

Phytophthora canker on plum tree

Though the disease comes from the roots, the dieback starts at the top of the tree, and these cankers usually become active during summer.

A peach tree with dieback from Phytophthora

It’s a nasty disease, and is responsible for many fruit tree deaths. But fear not, in many cases it’s perfectly beatable.

Of course the answer is in the soil!

A toad enjoying our healthy soil

Phythopthora is a fungus that lives in water in the soil, so it thrives in wet and waterlogged conditions.

But guess what eats it? Other soil fungi, the non-disease causing kind!

Healthy, well drained soil with lots of organic matter is the perfect breeding ground for these healthy soil fungi, and they will out-compete the Phytophthora.

This nasty soil fungus has been one of our main setbacks on the farm, particularly after the flooding rains we had a few years back. We lost a lot of trees, but our soil improvement work helped us to save a lot of sick trees we thought we would have to pull out.

A peach tree showing lots of new growth as it recovers from Phythopthora

The key to our soil improvement regime is (a) increasing the organic matter in the soil, and (b) making sure we have active (healthy) soil microbes doing their work! This is what we use:

  • compost (just spreading compost on top of the weeds or grass is good enough, as the worms quickly incorporate it into the soil);
  • compost tea — we aim to put it on at least three times a year (though even more would be great if we had the time);
  • microbe food — things like fish, kelp and humates are put through the irrigation system to feed the soil microbes;
  • occasional soil remediations, e.g. calcium.

Soil improvement is a long, slow, continuous process, but we’re consistently seeing improvements, so we know we’re on the right track!

You’ll find more information about how to identify and treat Phytophthora (and other common fruit tree diseases) in our short course “Keep Your Fruit Trees Free from Disease“.