Hugelkultur Above And Below In A Raised Garden Bed

I waited until now to post this as I wanted to see if this method would work and it has exceeded my expectations.

This spring I was trying to defeat the quail from dust bathing in the garden.

I got so frustrated as they kept digging up all the plants as they pressed their bodies into the soil and had a wonderful time spraying dirt, leaving wallows behind and upended plants.

And as they thoroughly enjoyed themselves they would stop briefly for a nibble at the newly planted plants just to keep up their energy for more dust bathing.

Or at least that’s how it seemed.

So… after the second round of planting seedlings, I had some bark mulch that we were using around the yard and I thought what the heck.

I would top the raised bed with it and the quail wouldn’t be able to bathe in the dirt.

Now keep in mind this isn’t your regular run of the mill bark mulch.

We get this from an actual sawmill up the road and it comes in big chunks and chips.

Some of it is so large that after we spread it in the yard I go around and pick up the big chunks to use a kindling for the fireplace.

I ended up dumping three large garbage buckets of bark mulch on the raised garden bed which is 5 ft x 12 ft and very carefully nestled it up to the newly planted plants.

In this bed, I had fiesta squash and corn planted together.

But before that, I better go back to the beginning.

This raised garden bed was one of the beds that had been modified as a hugelkultur bed.

You can read more about how we built it in a previous post and then here were the results.

Basically, you build the raised garden bed, fill the bottom with wood, sticks, twigs, grass clipping, leaves, and other organic matter.

The main ingredients is wood and the punkier (rotted) the better as it holds a lot of moisture and breaks down faster.

Then you put a layer of dirt over that and plant.

On the bed, in question, I had also added a layer of compost before I planted the squash and corn to add some additional nutrients to the soil.

Then planted the seedlings and topped with bark mulch.

As I was putting the mulch on I noticed that there was a lot of cedar bark in the mix and according to what I’ve read putting cedar on or in your garden is a no, no as it takes a long time to break down and emits a resin that will actually harms the plants.

But what the heck.

My motto is the plants will either live or die and I wasn’t about to take all the mulch off.

To my relief and amazement, the plants thrived.

Not only thrived but shot up like rockets and outdid the rest of my raised garden beds.

I attribute this to a couple of things.

1. It kept the quails away as if they couldn’t have a dust bath there wasn’t a reason to hop up on the bed
2. the slugs seem to prefer soil to travel on rather than bark mulch so I saw very little slug damage
3. suppress weeds
4. and the most important thing was it kept the moisture consistent in the raised garden bed.
5. but best of all it was producing mycelium in a very short period of time.

Moisture

One thing that I’ve noticed over the years with a raised garden bed is that when it gets hot or really windy that the bed dries out fairly quickly.

This was the reason that over the years I’ve been converting the raised beds to hugelkultur just so they retain more moisture.

And this has worked really well once the plants are established and have a good root system in place.

But when the plants are young I’m constantly having to water the beds as the top soil dries out and the seedling suffer.

I keep thinking I should put irrigation in the beds but as I do most of my watering from a 3000 gallon tank that collects rainwater, I find that there just isn’t enough pressure to make that a viable option.

So, by putting the wood chips on top of the soil when it rained they retained the moisture and kept it consistent which was a boost for the seedlings.

On my other beds, the soil on top would dry out.

Then you water and it drys out again.

Which when you think about it is a bit of a shock to the seedlings.

In many books and information on the web, there is an ongoing consensus that in order to get healthy plants it is best to withhold water and let the soil dry out as it helps their roots grow deeper to find water.

And I have to say I do this with my tomato plants. (rethinking this now)

Upon comparing the raised bed with the bark mulch with other garden beds without it, the one with the bark mulch was the winner.

When the other beds had dry soil all I had to do was to peak under the bark mulch and the soil was moist.

Consistently so.

The seedlings exploded under these conditions so it seemed that having consistent moisture was a benefit not a deterrent.

Just for comparison, I have tried other mulches in the past such as straw, leaves, compost and cardboard.

Each of them has its own benefits but none of them kept the soil so consistently moist as the wood chips.

Mycelium

Mycelium is a cobweb-like structure (fungus) that you see growing under the forest floor.

The fruit of these structures you’ve probably seen and eaten are mushrooms.

Studies like this one have found that the mycelium forms a web called a mycorrhizal network that interconnects with the forest trees allowing them to share water and nutrients with each other via the web.

This means that if my raised garden bed is producing mycelium then my seedlings and plants are interconnected.

The benefits of that are:

• improve water efficiency
• adds oxygen to the soil and promote root growth
• releases phosphate, nitrogen, and other micronutrients

This is all happening under the mulch so I don’t really see it but I am noticing how much bigger and stronger the plants are than in the other garden beds.

You can actually buy mycelium and put it into your garden or you can save yourself the trouble and add some bark mulch to the top.

Benefits

By first creating a hugelkultur raised bed (wood, organic matter, soil) the plants grow their roots long and strong reaching down for the moisture and nutrients created by the layers.

Then by applying wood chips on top of the soil, it seems to support the seedling growth thereby creating stronger plants that can then reach down to the layers below.

These chips are large enough that I can just pull them away from the top of the soil when I want to plant.

Seems like a win-win!

Cons

I wouldn’t do this with all my raised beds.

Just think about trying to plant carrots with those large chunks of wood covering the soil.

For those beds, I will stick to compost as a mulch.

On the other hand, as the wood chips break down and create their own compost in the future it will be perfect for planting small seeds.

I wouldn’t mix the wood chips into the soil it is said they will rob the soil of nitrogen as they break down.

Maybe next year I’ll put grow some nitrogen-fixing plants in the bed like beans.

Overall Assessment

This has been a great experiment in the garden this year and I will definitely do it again.

I actually ended up doing two beds with this method this year.

The one was a hugelkultur bed and the other one wasn’t.

The second bed was planted with all the brassicas like cauliflower, broccoli and cabbage.

These have finished and I’ve pulled them out and replanted.

The roots didn’t grow down like in a hugelkultur bed but overall the growth and produce were better than average.

The one thing that the bark mulch didn’t do was to stop the cabbage moths from laying their eggs on the brassicas and the resulting caterpillars munching on the leaves.

Hugelkultur above and below in a raised garden bed definitely worked.

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How to make a Hugelkultur bed in a raised garden bed click here
To read the test results of the Hugelkultur bed click here…

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Jigsaw Puzzle

If you need help with instructions click here.