Young vegetative plants (with 6–9 cm shoot length) of Equisetum arvense L. were collected from nature, washed with distilled water, and grown in plastic bottles in a defined nutrient solution with varying silicon concentrations.There was increased growth, as measured by dry weight, with increasing silicon in the nutrient solution. Plants with an adequate Si supply (40–80 mg Si/liter, replenished every 2 weeks) appeared normal and healthier than plants grown without added Si. Deficiency symptoms, such as necrosis of the branch tips, wilting or drooping of the branches, were observed in Si-deficient shoots.It was concluded that silicon is an essential element for the healthy growth of Equisetum arvense.