Ithaka Institut

Biochar Seed Wrapping

As seen with the biochar-compost substrates, the effect of biochar is more pronounced the closer it is applied to the root zone. Based on this observation we tried to wrap seed with various biochar-clay-nutrient mixtures. Especially in poor, eroded, and dry conditions seed germination and growth in the decisive early days are significantly improved.

Wrapping seeds with clay is an old seeding technique.  It protects the seeds while providing needed moisture, nutrients and structure for seed germination and growth. In addition, it protects seeds from being eaten by birds and other wildlife. Thanks to this method the risk is reduced that seeds germinate after the first light rainfall when the soil is only superficially wet which often causes young plants to dry out after a few days. Only when the clay is sufficiently soaked with water will seeds germinate properly.  Due to the insulating capacity of the clay, seeds are also better protected against frost as well.

The addition of biochar enhances these qualities as humidity, redox and nutrients are better balanced and probably also due to some plant growth signalling compounds of biochar's volatile compounds. Since 2012 we have tested different mixtures for a variety of seeds and application techniques. We have created wrapped seeds for faster prairie re-growth on ski slopes after the artificial snow melts. We have developed wrapped seed mixtures for re-vegetation of degraded soils and we are currently working on a system for direct cereal seeding.

We see huge potential for biochar based seed wrapping to reduce fertilizer useage, giving herbicide-free direct seeding the necessary advantage over weeds.  Biochar based seed wrappings provide a highly efficient, low dose and thus economic way for growers to use biochar.