How-to Hugelkultur

The subtropical jungle, returns

Perhaps I should say, how NOT to Hugelkulture instead? As these are the lessons I've learned about Hugelkulture in arid climates. Right now, it doesn't seem very arid, since the two-year drought has finally broken. Receiving another 17 mm yesterday. This is wonderful news of course, as it's allowed me to return to planting fruit trees again. But in so doing, I reassessed some areas I used Hugelkultur in. The past two years of drought, taught me a lot about their application.

Ironically, my experimentation with Hugelkultur, started back in 2016. Which turned out to be the last year we had a normal monsoon season. It was 2017, we started to see a steady decrease of rainfall, for over two years afterwards. So it was the perfect window, to see how Hugelkultur performed in one of our more unforgiving extremes. Remember, this is a growing system, and it needs to perform.

Raised hugelkultur growing bed, October 2016

the following year, they started to fail

Hugelkultur, was a growing system championed by Sepp Holzer, and it's designed to make use of woody material in food production. That's the simple explanation. With an excess of woody material on our property though, it made sense to experiment with this technique. However, the European wet climates this system was built for, gave it an edge of remarkable success, in those conditions. That same edge failed however, on the opposite end of the spectrum.

I have the perfect example to explain why...

Newly installed Hugel Mounds

In winter 2017, I set up some rather elaborate Hugel mounds. It took a while to design these, but they would soon be tested by our unforgiving dry. The design goals were simple though:

• Propagate Lemongrass for increased mulch material
• Placed near fruit trees to feed them with mulch
• Adjacent a pond and swale, to capture moisture and prevent nutrient leeching
• Raised for ease of access with handheld hedge sheers
• Act as a barrier to water overflowing, in a torrential downpour

These were great design ideas. The application however, demonstrated flaws in this design. Gotta love feedback for improving growing systems. Especially if your food supply is depending on it.

Over two years later

These are the same Hugel mounds, today. Only the photo is taken from the opposite direction. There's actually three mounds in total. One is hidden in the background. Lovely grass grows in the wet. Unfortunately, it's not all Lemongrass anymore. In over two years of progressive drought, I lost 8 huge clumps of Lemongrass, from the 13 planted. Most of what you see in the Hugel mounds, are regular grass. Which can't be trimmed with a mower.

Yet look at the flat ground, where the grass SHOULD be growing. It's Khaki weed. Known colloquially in Australia, as Bindi's. It's a name that covers any prickle, that gets caught in bare feet. The reason it's growing instead of grass, is because there's no topsoil. It's compacted red clay. Prickly ground-covers, always emerge in poor, compacted soils. It's nature's way of encourage animals, to stay off, while the soil improves over time.

Reconsidering the design

So I had common grass populating the Hugel mounds, where the Lemongrass failed. No grass populating the flat ground, and ultimately creating an evaporation point, around the mounds. It aided in the drying out of this area further. We did place bark mulch on the flat ground, several years ago. Anticipating the grass would populate eventually. But as you know, that didn't happen.

There was no way of predicting how profound and long, the recent drought would be. With the risk of bushfires, it wasn't wise to deliberately place woody material, near the house. At least stuff we would have to purchase, and import. There was enough here, naturally.

As a growing system in the dry, this was not a good performer. Ultimately, it did have it's advantages though. Worth installing at the time. Which revealed itself, as I set about planting new fruit trees in this area.

 Dissecting a Hugel Mound

The mounds did eventually break down, even in the very sporadic and minimal rainfall, experienced in the dry. Within the mounds themselves, revealed wonderful soil. Truly, beautiful, friable soil. And there were so many different lifeforms populating it. Millipedes, bugs, and ants came in to eat what they could drag out. But there was no ants nests in the mound, as I was cautioned might happen. I suspect because the termites love these areas, and they're both natural competitors for territory.

So I cannot fault the Hugel Mound's ability to grow good soil. It certainly used a lot of woody material, that would otherwise be drying out on the surface. But the application didn't propel my growing area enough, to justify the effort of installing in that location. There were better ways to install them, which I'll get too soon.

In order to plant more fruit trees though, I needed to change the topography, once again.

Improving the design

I dismantled the Hugel mounds, and spread that wonderful topsoil, over the compacted clay. I know grass will grow on this, if it grew in the Hugel mound. But it also helped flatten this area, which was more sloped than I wanted it to be. Changing the topography like this, will help capture more water in the soil. As gravity will hold it in place, rather than draining off the slope.

Looking into the future, when we get older, a mower will be easier to use here than a brush-cutter. So we're working towards making any flat ground where we can, for ease of maintenance. Looking back though, I can see WHY I wanted to experiment with Hugel mounds. Although with experience, I've realised, they're not so practical in arid conditions. The roots of plants, have to go down so much deeper to find moisture, if it's not coming from above.

A long awaited, new fruit tree ~

top mulched with saltbush

Here's partly, what this recent transformation was in aid of. New fruit trees. I swore when the drought broke, and the ground was properly saturated in our normal monsoon season again, I'd buy fruit trees. It doesn't make sense to establish them in the dry, when water is so hard to come by.

Not only because the tree will suffer (and maybe die) without that additional water, but I also have to fence them off from Kangaroos and brush turkeys. Both looking for food sources, which additional watering supplies. Naturally, when the rain came back in earnest, I was going to fulfill my promise of more fruit trees. Especially since four had survived in this same area, during the drought.

New variety

This is an Asian, Nashi pear. Reputed as being a low-chill variety, perfect for the subtropics. It's partnering with an existing, Clapps Favourite, European pear. Which is said to need more chilling hours, but still produces fruit here. So I'm confident the lower chill, Asian Pear will produce in this location too.

This particular tree will also help cross-pollinate my existing European Pear. I've heard the Ninjisseiki Asian Pear, may be better suited for this, but honestly - fruiting all depends on the rainfall. My European tree won't fruit, until the late Spring anyway, because we traditionally have a dry one. Which is why I'm fairly loose with recommendations, for any kind of fruit tree, coming out of dormancy. It all hinges on when the rain falls. So they all tend to fruit at the same time anyway!

Both these trees, are reputed for being self-pollinating. So not exactly, do or die!

Swale meets mound

Here is the same Asian Pear, in relation to the Swale. It's been full for the past few weeks. Notice the red clay, helps hold the water. I did tweak the sides of the swale, to make it easier to mow. But it has to empty first! Right now it's all mush. Bad for mowing - perfect for establishing trees.

All the fruit trees that survived in this area, are planted along this swale. There are patches with clay shelves, and others with sandstone. So some parts drain quickly, other holds. Ironically (and we didn't plan it this way) it's divided by a pond! Which makes it easier selecting which trees to plant on the swale, based on who likes it drier or not.

Click to enlarge

Two clumps of Lemongrass, did survive in this mound. The first one, was transplanted to the clay pot, seen in the very first image of this post. The second one, was planted back into where the mound was. I struck clay, as I dug into the hole. But I haven't had problems with Lemongrass in clay.

Nonetheless, I like to add a layer of woody material in the hole, before planting the lemongrass back It's not so much about drainage, as it is about the concept of Hugelkultur, aiding in soil building. The bark came from the Hugel mound, so populated with a lot of beneficial organisms. It should help the Lemongrass acclimatise, quicker.

Notice how shallow the roots are though? There wasn't much moisture for the Lemongrass to seek further down. Which is why in more arid climates, you're best placing plants at ground level, than above it.

Leftovers

These are the large tree branches, which came out of mounds. Mostly Black Wattle, which is a hardwood. Even though there's termite damage, it's not as extensive as you might think. Some branches, are still unbreakable. Perhaps if there had been more water, these would be more chewed up by termites. But I do know Black Wattle, is very slow to break down!

Surprised by their solid form, as I pulled them out of the mound, I nonetheless had a useful purpose for them...

Footpath, down to the house (left), new flatten area (right) ~

there's a sloped area, between them.

In our topography, this is where it makes the most sense to build Hugel Mounds. Not raised up on mostly flat ground, but on the slopes BETWEEN flat ground. It's difficult keeping soil on the slope, let alone making it! But the Hugelkultur growing system, acts as both gravity inhibitor and soil builder, at the same time.

So this is where I stacked the partly softened, but still solid, tree branches. You can see red clay in the footpath too. Clay is also in the sloped section, which is why I've always had problems establishing plants there. Being a north facing slope, it receives year round sun. The only time it doesn't, is when it's overcast.

Hugel Mound is fully dismantled

Speaking of which, it was overcast the whole two days it took, to complete this project. Which was kinder on the soil I was unearthing. Kinder on me too, as it was extremely humid! Very grateful the sun wasn't baking this area, all that time. Sometimes the weather works in your favour, and it feels like God is smiling upon you.

Knowing the weaknesses of this area being a heat sink though, I did have to get that soil covered, as quickly as possible. Because water has been so scarce formerly, and I want to keep it in the soil, I didn't mind purchasing inputs for a fast solution.

Covered

Sugarcane mulch, is more readily available in Queensland, than other forms of soft mulch. Plus it's not animal feed. I once spoiled my garden with lucerne bales, but since the drought, it's more valuable to a farmer with livestock. I don't want to put demand on the price, for the farmer. So we're fortunate sugarcane mulch, is readily available instead.

I did however, use copious amounts of freshly cut grass - left of the image. Some was pulled from the Hugel Mounds, others needed to be cleaned away from infrastructure - like the chicken coop. I'm drowning in waist high grass at the moment. Which I intend to turn into soil, for this area. The main reason I stacked grass, above that little sloped area was to prevent soil erosion.

Another addition

I introduced you to the Nashi pear, the Lemongrass, and the final tree to go in this area, was a Moringa tree. It's going to be chop and drop material, for the fruit trees as well. Several years old now, grown from seed, it's a rare survivor of the drought from my shade house. I lost a lot of plants in there, when I wasn't able to water. I was grateful the Moringa survived though. Not surprising for it's resilient reputation.

I did have to net around it, because although the kangaroos don't need the feed right now, I don't want them developing a taste for it. They regularly clean the pigeon peas and leucaena, in the dry springs we get. So I know the Moringa is a likely target, at some point too.

Nashi, Lemongrass and Moringa ~

large termite mound, poking through the grass at the back

I'm much happier with this area, now I've altered the growing systems. Hugelkultur is now placed where it can do the most good (on a slope) and removed from where it was a hindrance. It does work as a growing system, so long as it suits the application. Understanding your climate, natural resources and topography, all contributes to a better design.

I stumbled upon Hugelkultur, at the end of our wet years, which lead to severe testing through our dry ones. I'm really glad for that knowledge. Even though it was an excruciating wait, for the living systems to come back online again, But I now have a tangible comparison, to find the right application. As the worth of a growing system, is only determined by how it performs through both extremes.

I will still use Hugelkultur at Gully Grove. There's so much woody material here, it would be ludicrous not to. I'll just use it, how and where it benefits the most.