Horsetail and composting
I delivered a Compost workshop at a local allotment Open day at the weekend and there was considerable discussion about the problems caused by Horsetail. As a result I have enlarged the section on Horsetail on the Invasive Plants page Toxic Invasive Plant
As with many invasive plants and perennial weeds it is the roots that present the composter with the greatest problems. Cold composting will not kill them. They can survive in a cold compost bin for years the rhizomes laying dormant until the bin is emptied and the compost spread on the garden. They can also survive in many “Hot Composting” piles which do not reach and maintain a high enough temperature to prevent small pieces of root regenerating when the compost is spread on the garden. Many risk adverse composter’s choose to send these weeds to the Local Council composting site to be on the safe side.
Digging to remove the roots is difficult and will need to be continued over a number of years which is why many gardeners resort to chemical controls,
Hot composting operating at 40-60C will kill the seeds and turning the heap regularly will help maintain the temperature, If hot composting is to be used I would recommend regular measurement of temperature particularly on Allotment Community Composting sites where horsetail produced by one grower may be carried in the compost to plots cultivated by another plot holder.
As with other perennial weeds many recommend that they be:
- drowned by soaking in water until they are turned to a mush,
- dried out in the sun or
- heated by bagging with grass as a pre-composting treatment.
The positive note is that while it will not remove this invasive plant using it to make a foliar spray means that something positive can be achieved