Digging a Hügel

Couldn't have known what a big job it would be.

The single largest task we had planned for this spring was creating a large (about 12 x 4 metres, or 40 x 15 feet) new vegetable bed down in the bottom paddock.

We're nearing the end of our rolling programme of covering large areas with black plastic each year, for digging new beds the following year. The ground down there is quite heavy with clay, borderline boggy. The original intention was that it should be this year's potato bed, but when I started digging it, back in February or March, I soon concluded that it was far too wet and stony to be ready in time for planting potatoes! We found a better spot for the tatties and put this one on the back-burner for a little longer.

Happily, at just this time, we heard about Hügelkultur (literally mound- or hill-culture). This is a land management technique long practised in parts of Germany and Eastern Europe, in which marginal land is made cultivable by creating mounds of wood, woody waste from around the garden, plant and grass cuttings: basically whatever organic material is handy, with compost and soil over all. The result is a bed with a decaying core of organic matter that acts as a moisture store, while gradually breaking down, enriching and contributing to the soil.

Typically, the material is simply piled up on the surface of the ground, over an area of about one by two metres, to a maximum height of approximately one metre. In our case, the area we wanted to cultivate is considerably larger (of course, we could have just created a series of small mounds), and is also very windswept. Although we have planted hedges to break the wind, it'll be a few years yet before the shelter is really good and in the meantime we can't get into vertical gardening.

By this stage I was starting to realise the scale of it.

We decided to modify the method to suit our needs, inverting our Hügel and embedding it in the ground, so I started by digging a large trench. The first six to eight inches weren't too bad, coming up with the spade as hefty soil blocks, with some stones scattered throughout.

Couldn't have done it without the fishbox soil sifter.

Then came the 'stone zone'. A layer of another six to eight inches so packed with stones as to be impenetrable to spade or fork. I suppose at one time, 9000 or so years ago, this was the bed of a glacial meltwater runoff.

We had just invested in a Mantis tiller, which proved to be the very tool for the job. With that, I was able to gouge out the stone zone layer, into piles of earth and stone the we could shake through our homemade fishbox soil sifter. The soil was thus kept to go back on top and the stone added to our ever-increasing mound of rubble in the bottom corner of the garden.

Probably couldn't have done it without beer either.

Once underneath the stone zone, the ground was again penetrable to the spade, allowing me to dig out the deepest, central portion of the trench, down another 12 inches or so.

That's where the trench met the level of the ground water, and soon there was water pooling in the bottom of the trench, even though we were weeks into an unusually dry spell of weather. This hopefully means that the new bed won't ever need watering.

Now it was time to start filling it all back up again. We started out by sacrificing a couple of large sitka spruce firewood logs to the cause, providing the substantial, slowest-decaying core.

Step 1. Logs

Next came a layer of scorched gorse bush remains, which our neighbour had burnt off a nearby hillside the year before. Still woody matter, but much smaller pieces than the core logs.

Step 2. Brush

On top of that, we happened to have a very large pile of winter brassica ready to be cleared from the rest of the veg garden.

Spent winter brassicas

So, in it went. This will break down much more rapidly.

Step 3. Garden waste

We also chucked in some rotted manure at this point, for good measure.

Step 4. Manure

As the final, swiftest decaying layer, we spread in a load of grass cuttings.

Step 5. Grass

And then it was time to Mantis (yes, that is now a verb here) the soil back over top of all.

Step 6. Tilling and covering

The soil is, of course, still heavy clay. Very sticky when wet and easily compacted. So we added a bale of wood shavings (animal bedding type), to lighten things up a bit.

Step 7. Wood shavings to be mixed in

Soon it will be time to add squash seedlings. Hope they're going to like the new bed created especially for them!

Just add seedlings