Hugelkultur

Hugelkultur is a no-dig gardening method that uses mounds of logs and branches covered with soil to create growing space. Mounds are commonly used when growing pumpkins, melons, and other cucurbits. These “hills” help prevent waterlogged roots, prone to rot. Hugelkultur is something entirely different.

Sketch of hugelkultur (Wikipedia) CC BY-SA 2.5

​These mounds start out 3 feet high and wide. As decomposition occurs, the mounds collapse. After being built, mounds are normally left to rest for several months, though some people plant them right away. Since more decomposition is occurring during the first seasons of a hugelkultur’s life, heavy feeding crops, such as melons, squashes, cabbages, potatoes, and tomatoes are grown first, followed by less demanding crops, such as beans, strawberries, and peas, in later seasons. The average lifespan of a hugelkultur is 5 to 6 years.

Hugelkultur beds are generally positioned so is to be perpendicular to prevailing winds and slopes. For a more whimsical appearance, you can create hugelkultur in whatever shape suits your fancy, such as spirals or mazes. While enthusiasts claim hugelkultur can be used to redirect stormwater, these mounds do not have the strength or stability required of solid earthworks. Instead of protecting against flooding, hugelkulturs can cause even more destruction as floating logs and branches join the water flow.

Problems with hugelkultur

Before you get caught up in the hugelkultur fad, understand that there is, as far as I know, no scientific research to verify the claims made by hugelkultur fans. This doesn't mean the claims are false. It simply means that scientific studies have not yet verified the claims. There are some obvious problems, however.

Traditionally, hugelkulturs were recommended for counteracting “poisoned layers” of soil. This is a terrible idea. Plant roots will move through the mound and into the soil below. Using raised beds with soil barriers, or container gardening, are much better solutions.

Hugelkultur is also said to feed and water nearby plants. In nature, fallen logs do provide water and nutrients to nearby plants. This occurs because they are on top of the soil. As they decompose, they become more porous, storing water and releasing nutrients. These ‘nursery logs’ have long been a source of water and nutrition for young trees and other plants. Hugelkultur logs are underground and do not function in the same way.

​What is hugelkultur?​

Hugelkultur was started in Germany as a way to put woody debris to good use when, at the time, it was illegal to burn it. While proponents state that hugelkultur started “hundreds of years ago”, there is no proof to substantiate that claim. The term was first used in 1962 by Herrman Andrä, a German gardener, when he noted the diversity of plants growing on a pile of woody debris at his grandmother’s home. Andrä and others standardized the method, claiming that the rounded mounds increased growing area and nutrient availability, while storing moisture for growing plants.

How to build a hugelkultur bed

At first, hugelkultur was nothing more than long piles of logs, branches, twigs, and plant waste, such as straw, compost, or sod, covered with soil. In some cases, the design evolved to start with a dug trench or sunken area. The soil removed to make the trench is then used on top of the mound, before planting occurs. The trench method is more commonly used in sandy soils [In another method I found, cardboard, kitchen waste, and old clothing are also incorporated into the mound. Depending on the type of fabric, cotton and wool, as opposed to polyester and rayon, this may or may not be a good idea, respectively.]

​Other concerns about hugelkultur include the potential for nutrient deficiencies or toxicities. With all that decomposition going on, nitrogen deficiencies may occur. This can happen because the microorganisms responsible for breaking down plant materials use nitrogen as an energy source. (See nitrogen cycle) On the flip side, so much organic material is being used and broken down that nutrient levels can become excessive, creating toxicities within the soil and groundwater.

Also, the materials used to create the mounds can cause problems of their own. Cedar and walnut contain chemicals that slow the growth of other plants. Some branches, such as Chinese privet, will generate roots all along the buried branches and twigs, and take over the area. Because there is sod, water, soil, and nutrients available in a hugelkultur, weeds can also become a serious problem.

​If hugelkultur works for you, wonderful! If you haven’t tried it yet, you may want to put all those logs, stumps, or tree trunks to work in the garden in other ways. Larger pieces make attractive stumperies, while logs make excellent path markers. Ultimately, these woody limbs will break down, adding nutrients and improving soil structure but, as nature intended, these things take time.

Logs make a nice path edging