How to Build a Thermal Mass Wall for Your Water Garden (Step-by-Step)
A thermal mass wall is a dense, heat-absorbing structure positioned on the sunny side of your pond that captures warmth during the day and releases it slowly at night, smoothing out the temperature swings that stress koi, goldfish, and aquatic plants. Building one takes a weekend and requires just basic masonry skills, but the payoff is significant: you’ll see pond temperatures stabilize by several degrees, reducing shock to sensitive species and extending your growing season at …