How to Build an In-Ground Hugelkultur Garden Bed
Building an in-ground hugelkultur garden bed is an interesting garden method for developing very productive gardens. A hugelkultur bed is simply a variety of materials including wood, leafy material, straw, animal manure, soil amendments and native soil to create a very rich growing area. The traditional hugelkultur bed will be stacked very high, however, for urban homesteaders, an in-ground version may be a better option both practically and aesthetically.
The biggest benefit of a hugelkultur bed is they evolve into very rich gardens full of organic matter that break down slowly over time. As a result the materials cause a slow release of nutrients and minerals. Provided that you add the right components over the long term the garden will have everything it needs to grow vegetables and fruit shrubs. Along with these benefits as the buried wood continues to rot it retains moisture. This results in hugelkultur beds needing to be watered significantly less than traditional in-ground garden beds.
Overview – What is an In Ground Hugelkultur Bed
Hugelkultur is a German word that means mound culture or hill culture. This gardening topic has been popularized by Sepp Holzer, an Australian permaculture advocate. He made hugelkultur popular and written books on the subject. In its most traditional form, large logs form the base of the mound and it can be built up with smaller woody debris, compost, manure, and soil reaching a height of 6 or 7 feet. Provided that you have a need to use up large logs the traditional method may be best. However, due to the large size, it can be intimidating for average gardeners to undertake. Whereas in ground versions are not as intimidating and require less big wood.
An in-ground hugelkultur bed mimics many of the techniques used to create a traditional hugelkultur bed without becoming so massive. Instead of layering the material on the surface of the ground, an in-ground version requires the gardener to dig down one to three feet. This hole is then filled in with rich organic materials and covered with native soil prior to planting transplants or seeding.
Steps for Building a Hugelkultur Garden
The steps for building an in-ground garden bed with hugelkultur techniques is straightforward. In its most simple form, it is to dig a big hole and fill it with wood and other organic matter and fill the hole back in.
Step 1 – Dig the hole between one and three feet deep. Set the topsoil and subsoil to the side. This material will be used on the top of the hugel bed later.
Step 2 – Add larger pieces of wood to the bottom of the hole.
Step 3 – Fill in the gaps in the hole with smaller pieces of woody debris and branches. Add ramial wood chips or chips from an arborist to completely fill in the gaps as much as possible in the bed. If you have access to a local mushroom grower try and acquire spent mushroom blocks. Add these blocks into the mix of heavy carbon material to ignite the mycelium in the garden bed. It is possible to even get a harvest of edible mushrooms.
Step 3 – Add leafy material such as grass, leaves, plant matter like old vegetable stalks and leaves, chop and drop material, or prunings from a hedge.
Step 4 – Add in any additional carbon heavier materials like straw or bedding from animals that will have some uncomposted manure.
Step 5 – Place a layer of animal manure either fresh or composted on top of this layer of material.
Step 6 – Dump a load of well-composted material either homemade compost that has had time to age properly or purchased compost that is ready to go. If you make your own leaf mold at home this is a good time to add it into the mix.
Step 7 – Finish off the hugelkultur garden bed with a top layer of native soil used to dig out the hole that started the process. Get additional native soil from your property or acquire additional soil to complete the bed.
Step 8 – Water the bed thoroughly which will help everything to settle well into place.
Step 9 – Plant the bed with transplants or direct seed into the garden bed.
Start to Finish Pictures for an In-Ground Hugelkultur Bed
Supplies for Building a Hugelkultur Bed
Creating a hugelkultur bed can be done with tools that are likely already in the garden shed. It must be remembered to not overcomplicate your gardening projects. In other words source materials from around your property first. Second, look for free or nearly free resources from online marketplaces. In general you should avoid buying materials from a big box store in order to build a hugelkultur bed. The biggest component of building a hugelkultur bed is the labor involved with preparing the space and moving all the materials in place. Therefore, if you are doing more than a single garden bed on a weekend it can be a good idea to invite a few friends over to help.
Organic Materials for Hugelkultur Garden Beds
A hugelkultur bed uses a lot of the same materials that are used when making sheet mulch lasagne style garden bed. However, a hugel bed uses woody debris at the base.
- Large Wood Pieces – Ideally the wood is large in diameter. Bigger chunks will be slower to break down and have a much higher water holding capacity than just small branches. If the wood is already rotting then it is even better.
- Small Wood Branches – Branch material that is cut up to size helps fill in the gaps so the bottom of the hugelkultur mound is solid without a lot of air for soil to collapse and fill in. Ramial wood chips, which are chipped small branches from trees such as fruit trees, are an excellent source. Adding wood chips from a chip drop is also an acceptable option for filling the gaps in the larger wood pieces.
- Leafy Materials – Fresh “green” material that will add some nitrogen to the pile is essential as the wood is very heavy in carbon.
- Compost – Compost material that is either purchased or homemade.
- Animal Manure – either composted or still hot. Again with the large carbon input from the wood a hugelkultur garden can take a lot of nitrogen right out the gate.
- Native Topsoil – add to the surface layer for planting directly into.
- Additional Materials – inside of a hugel mound include: straw, spent mushroom substrate blocks, animal bedding, chop and drop plant material like comfrey or trimmings from a hedge, extra plant material from a recent harvest like corn stalks, broccoli plants, etc. and any other soil amendments that you may use to boost the soil microbiology in your gardens.
Tools for Building a Hugelkultur Bed
A quality garden shovel is needed to dig down to the depth of one to three feet deep.
Tree Pruning Saw
A sharp tree pruning saw is great for cutting off branches or cutting down to size larger-sized branches.
A large lopper is great for pruning larger branches from trees and breaking down branches into sizes that will fit the hugelkultur bed.
A pitchfork is great for moving lots of materials especially if you are using homemade compost or have partially broken down leafy material to add to the bed.
A wheelbarrow is not an essential tool, but again if you are moving materials around your property it makes the process easier.
A chainsaw is only necessary if the tree you are using to fill the bottom layer of the bed is too big for a pruning saw. Most in-ground hugelkultur beds are made with smaller diameter wood meaning a chainsaw is not an essential tool
An in-ground hugelkultur bed is a wonderful addition to any urban homestead. Whether the bed will be used for flowers, herbs, annual vegetables, or planting perennial shrubs. Although a lot of work is needed to create them they provide lasting benefits.
We like to grow vegetables and flowers in our hugelkultur beds for the first few years. Then transition the bed to perennials such as a blueberry patch. The blueberries benefit from the water-absorbing qualities of the rotting wood in the hugel mound. Giving the mound time to settle reduce in height before planting shrubs is adviseable. Otherwise you may have to worry about them having stability issues if the hugel mound collapses on itself. There are countless ways to maximize adding a hugel mound to your food forest. Therefore, I encourage you to experiment with them if you need to add organic matter to the soil.
Be prepared to watch the bed slowly sink in height over time. An in-ground hugelkultur bed that is three or four feet tall will slowly reduce in size over the next few years. However as it ages the material in the ground will break down and create a rich growing environment for many years to come.