Three leafy grass varieties, S215 meadow fescue, S37 cocksfoot and S51 timothy. were subjected to four dril spacings of 6, 15, 24 and 36 in. under two levels of nitrogen application. Over three harvest years, meadow fescue gave better seed yields with 6‐ and 15‐in, drill spacings. Cocksfoot gave very similar yields from 1.5, 24‐ and 36‐in, drills but a signincantly reduced yield from 6‐in, spaced drills. Timothy produced significantly higher yields at the 24 in spacing.The three varieties showed a significant response to nitrogen application.Aphids seriously affected the vegetative growth of meadow fescue and timothy at the wider spacings, but the 6‐in. drills m boths species remained relatively free of aphid attack, as also did the cock