Broccoli is part of the Brassica family and is high in vitamins and anti-cancer agents. There are a few varieties that come in purple and green, it is similar to Calabrese but is an over-wintering vegetable whereas Calabrese can be harvested before winter begins. 

Generally, you can sow broccoli from April-June outdoors and a bit earlier if you are sowing indoors. Sow the broccoli seeds in trays first or straight into their beds approximately 1-2cm deep and allowing them plenty of space apart due to the size that the plant will grow; about 30cm. 

You will want to protect your crop with netting/mesh because birds love broccoli, and they are also prone to white fly and slugs. 

A sheltered spot in well-drained soil is best with watering during dry spells, you may need to use stakes if you have a windy plot, and you can earth up the soil to taller stems to help this. 

You can stagger your sowing for a longer cropping season, as alike other Brassicas they tend to be ready at the same time and should be harvested when the buds have formed but are yet to flower. 

Dependent on sowing times and varieties, you can potentially harvest broccoli from the summer through until early Spring the following year. 
You can harvest the broccoli heads/spears by cutting the centre stem first followed by surrounding smaller ones. 

Fresh steamed broccoli tastes amazing, and you can also freeze florets of broccoli after blanching but not fully cooking.