Worm Castings

Worm castings are the finished product of composting worms, and they are one of the gentlest fertilizers you can put on a plant. The nutrients are already in a form roots can take up, yet the concentration is mild enough that there is no risk of burning, even on seedlings and houseplants.

Beyond feeding, castings bring beneficial microbes into the soil, which help plants take up nutrients and cope with stress. Gardeners usually notice deeper leaf colour and steadier growth within a few weeks.

Mix a handful into planting holes, work a thin layer into the top of container soil, or use it as a top dressing on established beds. Because it is so mild, you can use it right through the season without waiting between applications.