Eelgrass

Eelgrass forms a background of long, narrow leaves and spreads through the substrate by runners. Plan space for the established patch rather than choosing it only by the size of the plant in its pot. Plants sold as Vallisneria spiralis vary in leaf length, and similar species are sometimes traded under the same name. The name refers to the coiling female flower stalk; that behaviour occurs throughout Vallisneria and does not identify this species on its own.

Plant the roots in the substrate while leaving the leaf-producing crown exposed. Medium to strong light and a settled root zone support growth. The optimum temperature is 20 to 28 °C, with pH 6 to 8. Added CO₂ can improve growth; maintain adequate light and nutrition as the patch expands.

Separate rooted daughter rosettes from the connecting runners to propagate or contain the patch. Remove surplus plants before they shade their neighbours. Use a balanced plant fertiliser as directed. Iron fertiliser and liquid-carbon products serve different purposes; follow the directions for the specific product.