Abstract Three lamping systems were devised and evaluated for their suitability in providing energy for plant growth and development. These systems were based on three types of high-pressure vapour-discharge lamps (phosphor-coated mercury vapour, mercury iodide, and metal halide types) operated with red and blue wavelength supplementation. The vegetative growth responses of four plant species (sorghum, soybean, perennial ryegrass, and white clover) were examined. In general, plants grew equally well, and growth form and chemical composition were similar under all lighting systems. However, the metal halide lamp was found to be the most efficient tested and at the same time possessed the most uniform spectral distribution over the visible wavelength range.