Is there a way to build up the water-retention properties of a no-dig garden? The water runs through the layers very quickly and the plants wilt each day.
Hey JH, you can either cover the area with lucerne (straw) or mulch which will both provide a thermal blanket and the worms will also drag the vegetable matter down into the soil which will then help hold moisture - but this takes a while to happen.
The best quick solution is to add a soil wetting agent (surfactant) which will help the soil to absorb more moisture and retain it longer.
The best approach is to do both.
Here's a link to the Garden Shop where you can buy Yates Waterwise Concentrated Soil Wetter:
https://www.gardensonline.com.au/Shopping/GardenShop/Show_6555.aspx