While preparing soil for growing vegetables, I wanted to build a bed that would also use pruning waste and pieces of wood. I used the Hügelkultur approach to make a 200 × 200 × 40 cm garden bed with a corrugated sheet-metal frame. Here I explain the materials, filling sequence and points to consider from the project I shared on my Bahçe Sırları channel.
What is Hügelkultur?
Hügelkultur is an approach to building a growing bed by placing organic material and planting soil over wood. The German name refers to growing on a mound. Traditional examples form a raised hill; in my project, the filling stays inside a metal frame.
The purpose is to use organic materials from the garden and create a structure that decomposes over time. It should not be assumed to produce the same yield in every soil or eliminate watering. Wood decomposition, nitrogen balance and water retention all need attention.
An illustrative diagram of a mound-style bed. Mine has a flat top and a sheet-metal frame; this is not a scale plan of my project. Image: Genetics4good / Wikimedia Commons, CC0.
Dimensions and materials
The base covers about 4 square metres. Using the outer dimensions, its volume at 40 cm high is approximately 1.6 cubic metres. I did not fill that entire volume with soil: the lower part contains wood and other organic materials.
The main materials in the video are:
- Corrugated sheet metal and 40 × 40 mm metal corner posts.
- Intermediate supports to reduce outward movement along the long sides.
- Sheet-metal screws.
- Cardboard to cover the ground.
- Large wood pieces, thinner branches, green plant material and dry straw.
- Soil, well-rotted sheep manure and sawdust.
- Plastic sheeting for covering during the initial preparation period.
I bought the metal from a scrap dealer. The 450 Turkish lira mentioned in the video was what I paid for the sheet metal alone in March 2024. It is neither a current price nor the total project cost. I used posts I already had and assembled the frame with screws rather than welding.
1. Preparing the ground and frame
I first hoed the area to clear weeds. Then I positioned the metal sheets and drove the corner posts into the ground. I added intermediate supports to reduce bowing along the two-metre sides under the pressure of the filling.
Total area is not the only consideration. Reaching the middle of a two-metre-wide bed can be difficult. Plan access from both sides, paths and maintenance without stepping on the soil.
If you use metal, cover sharp edges. Check the previous use of reclaimed material and whether it carries unknown paint or chemical residues. The permeability of the ground underneath matters too: building a frame does not by itself solve drainage problems.
2. Cardboard first, then large wood pieces
I laid cardboard on the ground to reduce light reaching the weeds below. Thick wood went on the bottom, with thinner branches above.
The source of the wood matters. Do not use painted, treated, glued or chemically processed wood in a vegetable bed. Remove tape and plastic coatings from cardboard. Large gaps between wood pieces can allow soil to fall through and cause uneven settling.
3. Adding plant material and soil
After the woody layers, I added green plant material and dry straw. I watered during preparation, then added the soil. The video also shows stages where I added sawdust and well-rotted manure.
I do not consider this sequence a fixed recipe. What matters is leaving a deep enough upper layer with a suitable structure for root growth. In a bed only 40 cm high, such as mine, too much lower filling leaves little room for planting soil.
Green plant waste and straw play different roles. Their balance with dry woody materials influences decomposition. Avoid thick, compacted layers of green clippings with little air, and do not use clippings treated with chemicals unsuitable for the bed.
An important distinction about sawdust
In the video, I used sawdust between layers and on the surface to help retain moisture. However, mixing sawdust into soil is different from leaving it on top as mulch.
Oregon State University explains that small wood particles, especially when mixed into soil, can temporarily tie up available nitrogen as they decompose. It would therefore be misleading to present the generous sawdust use in my video as a filling recipe recommended for everyone.
For a new bed, preparing the upper planting layer with mature compost rather than a large amount of fresh sawdust gives you a more controlled starting point. Use surface mulch so water can still reach the soil, and do not pile it against plant stems.
Sulfur and pH: measure first
The video includes a stage where I apply sulfur to lower my soil’s pH. This is not a step required in every Hügelkultur bed. Sulfur or lime should be chosen according to soil analysis, the intended crop and the product instructions.
Rather than treating one pH number mentioned for tomatoes as a universal target, consider the growing conditions together. Purdue University, for example, gives a suitable range of 6.2–6.8 for tomatoes. Trying to acidify soil without measuring its pH may be unnecessary.
I also do not recommend sulfur as a general insect repellent. I give no application quantity here because the amount cannot be calculated from the bed’s dimensions alone.
4. Covering the surface before planting
Finally, I spread sawdust on top and covered the bed with plastic. I wanted to prepare it while the seedlings were growing and reduce moisture loss. At planting time, I planned to remove the covering and move mulch aside at each planting spot.
Plastic covering is not an essential part of Hügelkultur. If used, the moisture and temperature beneath it need checking. Waiting for a while does not mean the wood has fully decomposed or manure has matured. Use properly composted material rather than fresh manure for growing vegetables.
What to monitor after construction
The video shows construction and preparation. I do not infer a particular increase in yield or percentage of water saved from it. Afterwards, watch:
- Soil level: Organic filling may settle as it decomposes; top up with suitable soil and mature compost when necessary.
- Moisture: The surface can look dry while lower layers remain wet. Do not judge watering only from the surface.
- Plant growth: Yellowing or poor growth does not automatically mean nitrogen deficiency; consider watering, roots and nutrition together.
- Plant spacing: Overcrowding four square metres can make maintenance and air circulation difficult.
For me, the most valuable part of this project was using materials from the garden to make a defined growing space. Anyone considering a similar bed should first plan access, assess the existing soil and allow a sufficient upper root zone. The filling and later care matter just as much as the visible frame.
Construction stages in the video
Watch the frame assembly and filling in the video, or jump to a stage:
- Sheet dimensions and frame preparation — 00:34
- Cardboard and large wood pieces — 03:02
- Plant waste, watering and soil — 05:08
- Surface cover and preparation for planting — 09:10
Further reading and sources
The practical account is based on my Bahçe Sırları video. For the technical explanations:
