Brussels may grow a bit too tall for you to consider for your windowbox, (up to 75cm) but I include them here in case you still want to try them. For summer crops sow seed under cover in late winter and for winter crops sow from early to mid-spring. Plant out when frosts have passed and when the plants have at least 3-4 adult leaves. Keep plants well-watered until they become established. Remember you can also use the leaves as greens, though don’t deprive the plant too much or it won’t have the energy to put into the sprouts!
Sow seed: 2cm deep, 60cm apart
Varieties: Bosworth, Cascade, Diabolo, Romulus, Wellington