Can bark mulch help retain soil moisture

Few gardening tricks rival laying a soft quilt of bark mulch when soil looks thirsty. Each chip acts like a tiny tile, intercepting sun-light and softening rainfall. The mulch curbs evaporation by cooling the surface; on a July afternoon, slip a hand under five centimetres and feel the chill. Irregular pieces allow air to pass, keeping dampness sweet.

Moisture savings start the moment the layer settles. Water that would normally bead and run away now drips between gaps and sinks gently, held by capillary tension within the bark. As the top centimetre dries, vapour meets the cooler underside of the mulch and condenses, effectively recycling itself overnight. In light soils this can cut irrigation by half, while in clay it stops surface cracking that wrenches young roots.

Over time, the mulch breaks down, becoming spongier and even better at holding water. Topping up once a year keeps the barrier intact; specialists at AHS LTD suggest renewing whenever you can see bare earth poking through. Combine the mulch with organic feeds or green manures and you create a two-layer system: mulch above, sponge below. The result is fewer hosepipe sessions, steadier growth, and beds that shrug off heatwaves with quiet confidence.