To mulch or not to mulch?

Our fruit growing study tour of the USA got us thinking about mulch, as we saw a number of different approaches to it in our travels.

An apple tree mulched with woodchips at the Maine Heritage Orchard
An apple tree mulched with woodchips at the Maine Heritage Orchard

Of course it wasn’t hard to find orchards where the weeds have been completely sprayed out with herbicide, and mulch isn’t needed because there’s no plants left.

Yuk! Don’t do that!

The chemicals are bad for your health, the weeds grow back and need spraying again ($ straight from your pocket to the chemical companies), but worst of all – it’s really bad for the soil and kills the natural fertility system that trees need to get their nutrients (more $ straight from your pocket to the fertiliser company).

So what to do? Should you just let the weeds grow? Won’t they compete with the trees?

For young trees this is somewhat true – it’s definitely helpful to keep the weeds (or you could call them precious understory biodiversity plants) down while the tree’s roots are getting established, and we saw this in action at the Maine Heritage Orchard in Unity, Maine.

This orchard was planted not that many years ago on the site of a disused gravel pit, so major soil building and remediation has been the order of the day.

Hardwood chips have been extensively used, not only to mulch the trees when they were planted, but also to build paths, build soil more generally, and as an ongoing weed suppression tool even as the trees mature.

A tree in Michael Phillips' orchard which was mulched with woodchips when planted and has since been allowed to revert to natural understory
A tree in Michael Phillips’ orchard which was mulched with woodchips when planted and has since been allowed to revert to natural understory

We saw a different approach in Michael Phillips’ orchard in New Hampshire.

He also uses woodchips on young trees, but welcomes a wide diversity of understory plants as the trees grow, using mulch in a more ad hoc way.

There is widespread agreement that if you are going to mulch, hardwood woodchips are preferable.

This is because fruit trees prefer a fungally dominant soil, as we explain in our Soil Biology and the Soil Food Web short course.

Understanding the amazing world of soil microbes that are key to the Natural Fertility System will change the way you think about soil, fertiliser and mulch forever.

So, to mulch, or not to mulch?

After everything we’ve seen, we’re still in favour of mulching while the trees are young, and then transitioning to either a natural or cultivated understory – a “living mulch”!

Animals and fruit trees

Do you have animals around your fruit trees?

We’d never grazed animals in the orchard before (apart from the ones we don’t want, like kangaroos, rabbits and hares), until Tess Sellar joined us here at the farm and brought her lovely dairy cows.

Tess and Ant (who now runs the orchard on the farm) have been experimenting with grazing the cows in various orchards.

In winter when there are no leaves on the tree it’s wildly successful, with the cows making good use of the feed (saving Ant having to mow), leaving behind lots of fertiliser, and only causing minimal damage to the trees.

Cowpats in the orchard providing natural fertiliser
Cowpats in the orchard providing natural fertiliser

However in summer they quickly discovered that it’s a different story when the trees have leaves – turns out cows absolutely LOVE fruit tree leaves.

One of Tess' cows munching down on an apricot tree
One of Tess’ cows munching down on an apricot tree

If you can get the logistics right to get the benefits without the damage, fruit trees and grazing animals are a natural mix, and in fact have a long tradition of being farmed together.

But it’s a very uncommon practice in modern orchards, and so we’ve been glad to be part of the ANOO network (the Australian Network of Organic Orchardists) to learn from the experience of other small-scale organic orchardists – because that’s exactly the experience we can then bring to you to try out in your backyards/small farms.

Within the ANOO network there are growers using sheep, cows, pigs, chickens and geese in their orchard, and every year it’s a hot topic of conversation at the conference.

Here’s a couple of things we’ve learned so far.

Phil Marriot has been grazing Shropshire sheep in his organic orchard. Phil finds that using the Shroppies to control the weeds under his trees brings great benefits – keeping the grass short and thereby helping to put more carbon into the soil, providing free nutrition for the trees delivered exactly where it’s needed, helping to control pests and diseases, cleaning up waste fruit from the ground, and of course converting waste (grass, fruit) into useful products like meat and wool.

Sheep grazing in a cherry orchard
Shropshire sheep grazing in a cherry orchard
Photo: Phil Marriot

While generally happy with the benefits, Phil warns that large animals will routinely eat the bottom metre or so of the foliage from both his cherry and lemon trees (as you can in the photo above).

He’s also spent a few years building up a herd of quiet, well-behaved animals that get to go in the orchard – any naughty ones are immediately banished, before they can spread their bad habits to their buddies.

Matthew Tack from Our Mates Farm in Tassie runs Wiltshire Horn sheep under his apple trees, and returned from a trip away to find this damage (below).

Sheep damage to an apple tree trunk. Photo: Matthew Tac
Sheep damage to an apple tree trunk.
Photo: Matthew Tack

Matthew and his wife Coreen are big fans of using animals with fruit trees, but warn of the dangers of letting the animals run short on minerals. The sheep were left in an area that they thought would have been big enough to feed them for 2 weeks.

“It goes to show how important minerals are! These trees fortunately are well established and should recover. Most of this damage is from last year’s wethers.”

One of the other big issues with keeping animals with fruit trees is protecting them from predators – but more on that in another blog.

If you’re interested in having animals around your fruit trees, we wrote Fruit Tree Care for Animal Lovers just for you! It will guide you through the pros and cons of including various animals and helps you figure out which will suit you best.

Fancy a cup of compost tea?

Having our morning cuppa - of tea, not compost!
Having our morning cuppa – of tea, not compost!

We’re always banging on about soil being the foundation of your entire food growing system, and how important it is to be constantly improving it.

So one of the common questions we’re asked, is “how?”

There are lots of techniques available to help you improve soil, like adding aged chicken manure, and compost (and we’re big fans of them). However one of the most useful (though least understood) is brewing your own compost tea.

We brew it on a big scale (as you can see in the photo below), but it’s also easy to make on a home garden scale.

Our 1,000 L compost tea brewer set up for demonstration at a workshop
Our 1,000 L compost tea brewer set up for demonstration at a workshop

So, what is it? It’s probably easiest to start with what it’s NOT, which is compost extract.

Compost extract is made by putting compost in water and swishing it around or leaving it to soak. You can do a similar thing with weeds to make a weed tea or weed extract. They’re both fantastic things to do, but all they do is to put the nutrients and any microbes present into solution.

This method doesn’t increase the number of microbes in the brew, and that’s the point of compost tea.

Hugh showing off his bathtub full of rich worm castings, which will be used to make compost tea
Hugh showing off his bathtub full of rich worm castings, which will be used to make compost tea

To brew compost tea we start with a small amount of something that’s rich in microbes, e.g., good compost, worm castings, or leaf litter from under a mature gum tree are all perfect for this. Then we put the source material in water, agitate it to knock the microbes off, then add microbe food and oxygen for 24-48 hours and voila! The microbes breed like…well, like microbes (that is, REALLY fast when conditions are right).

Components for the compost tea brewer
Components for the compost tea brewer

This turns a small amount of healthy microbes (bacteria, fungi, nematodes, and protozoa) into a huge number in a very short time.

On the farm we always check the brew to make sure we’ve actually got the right kind of microbes, but that’s not necessary in a home-brew situation, as long as you follow the guidelines.

Hugh checking the compost tea to make sure it's full of microbes (and not just brown water!)
Hugh checking the compost tea to make sure it’s full of microbes (and not just brown water!)

Then we just put the tea on the soil under our fruit trees, and let the microbes go to work. 

If you want to know more about this simple and very effective method of quickly building healthy soil, we’ve designed a short course just for you! It’s called The Art of Compost Tea, it includes plans for making a home-sized brewer, and you can download it here.