Tasty edible leaves all year round. 

You may sow straight into the ground or as I prefer, start indoors then plant outside when frost is definitely past which is usually around mid May and at the latest.

Indoors

Sow indoors from April to early May in seed trays then plant into the soil outside.

Outdoors

Sow outdoors in late spring, in the ground or in pots .

I like to spread compost over the soil before planting.

Weed regularly and water well in dry weather.