Courgettes are so easy to grow – and you get so many courgettes from each plant – expect three or four a week if you grow your own! Courgette plants do like to spread out (about 1m 2) but you can always plant them in a growbag if you’re short of space.Back to Vegetables A to Z.row. Two weeks before planting or sowing seed outdoors, make planting pockets 90cm (3ft) apart for courgettes, 1.2m (4ft) for marrows, 90 cm (3ft) for bush plants of summer squashes and 1.5m (5ft) for trailing plants of summer squashes.