Gardening with biochar

Biochar is one of the most useful soil additives you can use, and while you can add it any time of year (like compost), autumn is a great time to do it before your trees go to sleep in winter, to boost the organic matter in your soil and provide more habitat to help your soil microbes survive over winter.

In the first biochar workshop we ever went to a few years ago, the presenters started by saying “Let’s clearly appreciate and understand how biochar is truly amazing and differs from fertilisers or other gardening soil additive products.”

Well, that piqued our interest, for sure. They went on to explain that one of the ways biochar is unique is that it acts on four aspects of soil at the same time:

  • physical
  • hydrological
  • chemical
  • biological

What is biochar, we hear you ask, and why should we care? Basically, biochar is just charcoal produced in a special way from plant matter and stored in the soil.

Biochar...just like charcoal
Biochar…just like charcoal

It’s brilliant for the soil and your fruit trees (we’ll tell you why in a minute), but one of the best things about it in these times of climate change is that it’s a stable, long-term way of taking CO2 out of the air, and putting it back in the soil, where it belongs. It’s not much to look, as you can see – it just looks like charcoal.

Making biochar is one of those skills (like making compost tea) that can seem a bit fiddly at the beginning, but once you know what you’re doing and you’ve got a system in place it’s a fantastic way of providing your own top-notch soil amendments, basically for free.

Learning how to make biochar at a workshop at the farm
Learning how to make biochar at a workshop at the farm

After all, it’s been produced for thousands of years (you might have heard of the amazing terra preta highly fertile soils that were created in the Amazon basin through use of biochar), well before modern technology was available, so it can’t be that complicated!

Making biochar in a milo tin
Making biochar in a milo tin

So, why is it good for fruit trees? The main benefit is that it increases soil fertility, primarily by increasing the amount of organic carbon stored in the soil.

But there’s also lots of evidence now that biochar also provides a perfect habitat for soil microbes and stimulates their activity, making your soil much more biologically active. It also improves cation exchange capacity, which is a measure of the availability of the nutrients in your soil.

You can turn ordinary biochar into “superchar” by innoculating it with things like compost tea, worm tea and microbe food, as Lann demonstrated at the workshop. This charges the biochar with both microbes and microbe food before you put it in the soil, reducing the time it takes for it to start working its magic.

But it doesn’t stop there, there’s lots of other benefits, including:

  • it improves water quality,
  • it increases retention of water in soil, and 
  • it helps nutrients stay in the soil rather than leach out.
Healthy soil with lots of organic matter and microbes
Healthy soil with lots of organic matter and microbes

If you want to find out more about the microbes that will move into the biochar “hotel” you provide by adding biochar to your soil, and exactly how vital they are to your soil health, take our Soil Biology and the Soil Food Web short course.

Thanks to John Sanderson and Lann Falconer, both Environmental Engineers for Earth Systems, for their fantastic biochar knowledge and workshops. Read our detailed blog about their workshop here.

Summer pruning

There’s a lot of confusion about when is the best time to prune fruit trees, but we reckon it’s much easier to approach pruning with the mantra that there’s no “right” or “wrong”, there’s just cuts, and consequences.

There's no right or wrong way to prune, just cuts and consequences
There’s no right or wrong way to prune, just cuts and consequences

We think this approach takes the pressure off so you can feel like you can have a go, which is when the real learning starts.

So the question is, what’s the likely consequence of pruning your trees in summer?

We’re not big fans of rules when it comes to pruning — we find they actually confuse people, and can lead to inexperienced pruners making cuts that can have disastrous consequences.

It’s much better to understand the principles behind pruning, so that you can fall back on them to make up your mind about when to prune.

Our Pruning By Numbers system is based on 10 pruning principles, but the two that are most relevant here are #3: Winter pruning encourages vigour, and #4: Summer pruning slows growth.

Without getting too deeply into the physiological reasons behind these principles in this blog, you can use them to have a think about when you might want to either encourage vigour (i.e. vegetative growth) in your tree, and when you might want to slow growth down a bit.

And remember, they’re just principles — they just tell you what’s more likely to happen. There’s very few definites in the wonderful world of fruit growing!

Pruning young trees in winter encourages strong growth

So pruning your fruit tree when it’s dormant in winter is more likely to encourage the tree to grow strongly in response to the pruning cut — so this might be the best time to prune young trees that you want to encourage to grow big and strong (and then become fruitful) as quickly as possible.

Pruning your tree in summer tends to result in a smaller growth response from the tree — so this might suit a really big tree that you’re trying to renovate, for example.

Some other things to think about in deciding when to prune are:

  • disease — pruning in warm weather helps the cuts to heal quickly and reduce the introduction or spread of disease,
  • fruit quality — reducing leaf canopy with summer pruning can reduce the size and sugar content of the fruit,
  • fruit colour — less leaves allows better sun penetration to the tree and higher coloured fruit,
  • sunburn — a bushy leaf canopy can provide protection to vulnerable fruit,
  • root health — summer pruning can reduce root growth in a tree,
  • ease of pruning — it’s much easier to see what you’re doing in winter when there’s no leaves on the tree.
Summer pruning with fruit on the tree can affect both the fruit and the tree
Summer pruning with fruit on the tree can affect both the fruit and the tree

So for example, pruning a fruit tree in summer while it still has fruit can have a very different outcome to pruning it after harvest.

Summer pruning after harvest tends to slow the tree's growth without affecting fruit
Summer pruning after harvest tends to slow the tree’s growth without affecting fruit

So rather than stressing too much about when is the right time to prune, just remember that it doesn’t really matter, you’ll just get different consequences from doing it at different times of year.

And what a great way to learn! If you really think about when to prune and why, and then pay attention to what happens as a result (pro tip: take before and after shots), you’ll become quite an experienced pruner surprisingly quickly. If you still feel you need some help making the decision, take our Summer Pruning Short Course first.

Happy pruning!

Becoming an experienced pruner is an important part of getting great fruit yields
Becoming an experienced pruner is an important part of getting great fruit yields

How to Make Pink Lady Apples Pink

Do you grow Pink Lady apples? Ever wondered why sometimes they’re a gorgeous dark pink colour…

Beautiful dark pink Pink Lady apples
Beautiful dark pink Pink Lady apples

… and sometimes they’re pale? These two examples are both from the same trees at our farm (in different years). So, what’s the difference?

Pink lady apples that are pale in colour
Pink lady apples that are pale in colour

There are a few factors that determine the final colour, and the main one is the weather, but maybe not what you think!

Hot weather can bleach the colour out of the apples, and in fact we need cool nights and mornings for the apples to turn a lovely dark pink.

However they also need a certain amount of regular sunlight hitting the apple, so if you have a dense leaf cover on your trees, the apples that grow in the shade under the leaves are also likely to be pale.

Apples growing in the shade won't colour up as well
Apples growing in the shade won’t colour up as well

This is one of the reasons why you might choose to do a bit of summer pruning on your apple trees, to reduce the density of the canopy and allow sunlight to penetrate the whole tree. But having said that, this is mainly a strategy used on commercial orchards to get better colour in apples, because they’re under pressure to provide uniform looking “perfect” apples.

Pink lady apples packed and ready to go to market
Pink lady apples packed and ready to go to market

Most home-growers don’t care so much how their apples look as long as they taste great, and so are less likely to prune for cosmetic reasons alone.

Typical home grown pink lady apples with spots, blemishes, and uneven colour
Typical home grown pink lady apples with spots, blemishes, and uneven colour

The last thing that may affect the colour of your fruit is the cultivar (or specific variety), as there are a few different variations of Pink Lady that have a different colour profile.

For example, Rosy Glow is a much darker pink colour compared to the more traditional Cripps Pink (the apple most commonly known as Pink Lady), for example, but they are still sold as ‘Pink Lady’.

A bin full of beautiful Pink Lady apples
A bin full of beautiful Pink Lady apples

Do you have apple trees? They’re one of the most common fruit trees found in backyards, so we’ve gathered all our apple-specific growing tips into a single online course called Grow Awesome Apples.