Steep garden beds formed over a mound of rotting logs prevent soil compaction, hold onto water like a sponge, provide nutrients for decades, create more surface area for crops and an easier height for harvesting.
If you’re looking for the most efficient raised garden bed design ever, look no further than hugelkultur.
Pronounced hoo-gul-culture, hugelkultur is the centuries-old German practice of building hill- or mound-shaped garden beds over piles of rotting logs.
It might sound strange, but as the logs decay over the years, they provide slow-release nutrients for your potatoes, tomatoes, or whatever else your heart may desire to grow.
Austrian permaculture expert Sepp Holzer recommends digging your garden bed about a foot deep and laying long logs (or even tree trunks) vertically in it… stacking them up with wide base and using fewer and fewer as you go up to form a narrow ridge.
Cover that with branches, wood chips, leaves, grass clippings, compost and then soil and you’ve got a self-watering garden bed with at least 20 years of fertilizer in it!
The logs soak up the rain like a sponge and then release it into the soil during drier times. You actually may never need to water your garden again after the first year, except during times of drought.
They also provide a steady supply of nutrients as they break down – a couple of decades worth, depending on whether they are hardwood or soft wood.
The shape and structure of the hill or mound also helps prevent soil compaction, creates more surface area for planting, and makes harvesting easier.
It also creates several microclimates, so that you can put plants requiring less water and more sun near the top, and those requiring more water and less sun near the bottom.
The one nutrient hugelkulture garden beds don’t have enough of at first is nitrogen, as the logs release it when they start to decay, so legumes, and other nitrogen fixers, are a good thing to plant during the first year.
For more detailed instructions, see Farmer’s Almanac.