12/10/2026
Why do we use 7 mm bluestone screenings in our VEG wicking beds? 💧🌱
We put six materials to the test to see how high water would rise through capillary action. Sand was quickest initially, but the 7 mm screenings caught up after 24–48 hours. They also outperformed the same-sized scoria, while aggregates 10 mm and larger showed less capillary rise.
Our preferred choice for over 10 years, 7 mm screenings hit the sweet spot: strong wicking, water storage, fast sideways water movement when filling, and a stable reservoir that supports the soil above. They’re also economical, readily available and easy to work with, making them our overall winner.
No drainage cells or networks of pipe needed, just a short length of slotted agi pipe to help distribute incoming water. Better capillary rise means moisture can keep reaching the soil as the reservoir level drops.
📷 Left to right: 7 mm screenings, 10 mm aggregate, 15–20 mm bluestone, 7 mm scoria, 20 mm scoria and sand.
VEG has been installing wicking beds and refining their design since 2009, helping people grow abundant edible gardens. Want to learn more? Visit wickingbeds.com.au for our Wicking Beds 101 guide, and join our mailing list for practical tips for an easy, productive edible garden.
www.wickingbeds.com.au