I would use Coco-Wet or another rewetting agent as the surfactant of choice, rather than a detergent. Of course, the key is not allowing bark particles to drop below that 30% moisture content benchmark that constitutes the turning point at beyond which the bark becomes difficult to rewet.

If you happen to have Turface fines available, mixing a small amount into your soil will help rewet soils at the second watering. The Turface immediately soaks up any water it contacts; then water passes into the bark by diffusion, effectively breaking the bark's tendency to repel water.

Al

Poke an ice pic size hole(not too big) in the bottom of a two liter soda bottle,fill it with water and place so it drip,drips on you soil ,this will give it some time to s ooak in.
Or soak your container in a larger container of water.

I usually have luck with warm water.