Our design team nailed it with this one! This clever system adapts to practically any planter. 15 3 4" fully expanded, it compresses down to 8". The fill tube is height adjustable too, so you can use Most blueberry problems aren't caused by lack of fertilizer they're caused by the wrong soil conditions Blueberries LOVE acidic soil and healthy fungal networks around their roots. If your plant has: Wrought Iron 33" Spear Fence Window Box Wall Planter Selecting Planter Liners Plant Pot Size Guide Jacksons Nurseries