The nutty flavour of arugula - also called rocket or roquette - adds piquancy to salads. The dark green, lobed leaves of common arugula (Eruca sativa) form a loose, open bunch that can reach 15 to 25 centimetres across before the plant bolts. Wild arugula (E. selvatica syn. Diplotaxis tenuifolia) is about half the size, with smaller, more deeply lobed leaves. It has a stronger flavour and is slower to bolt.
Sow in spring as soon as the ground can be worked, planting seeds six millimetres deep, 2.5 centimetres apart in rows 15 to 20 centimetres apart. When leaves of seedlings touch, thin to 10 centimetres.
Arugula is ready to pick 28 to 35 days after sowing for common arugula, 49 to 56 days for wild. Cut off individual leaves, cut off the entire plant just below the root attachment or pull up the plant.
Mustard (Shown right)
Leaf mustard (Brassica juncea) is large-leafed and pungent, and includes colourful varieties - most mature in 45 days. Milder and slower to bolt, mizuna mustard (B. rapa var. japonica), widely grown in Japan, has deeply cut, feathery leaves.
Plant seeds six millimetres deep, 2.5 centimetres apart, thinning first to five, then to 10 centimetres - 20 to 30 if growing for cooked greens - when leaves start to touch. Once plants are 10 to 15 centimetres tall, pick individual leaves or cut the entire plant two centimetres or more above the crown; it will regrow and can be harvested four or five more times.
Cress adds a peppery taste to salads; it can also be used in sandwiches and as a garnish. Watercress (Nasturtium officinale), the most familiar type, is a perennial that grows wild in streams. Upland cress (Barbarea verna), a hardy biennial, tastes similar but is easier to grow.
Watercress can be seeded outside in a rich, neutral soil (pH 7) kept constantly moist. Sow seeds three millimetres deep and thin to 10 centimetres apart when leaves start to touch. Harvest by snipping off the top eight to 10 centimetres of the plant until small, white flowers appear in early summer. Plants mature in 60 days; stems placed in a glass of water in the refrigerator will stay fresh for up to a week.
Upland cress grows best in rich, moist soil and tolerates some shade. Sow six millimetres deep in rows 25 centimetres apart, thinning to 15 centimetres apart when leaves start to touch. In most of Canada, mulch plants before it snows to enjoy spring greens. Matures in 50 days, but outer leaves can be harvested as soon as the plant produces a rosette of leaves. As the plant ages, harvest milder-tasting leaves from the centre.