Calabrese is generally the well known ‘Autumn Broccoli’ so popular in the supermarkets and green grocers after the summer – though all-year cropping is now being developed! Broccoli sold is Calabrese grown! (There is also sprouting broccoli - green or purple. These are not Calabrese.)
It is different to purple and sprouting broccoli in that it normally develops a single central head – though after cutting, it will also sprout a few small heads which are no less tasty that the original central head.
It is a valuable addition to the vegetable garden, and best suited to the open ground rather than trying in containers. There is no mystique about how to grow Calabrese. The main confusion is with the name! It is sold as Broccoli.
Calabrese – Broccoli – generally prefers a good fertile soil in order to grow a good central head. The centre is actually a mass of tiny flower buds. Rich soil will help the head to develop rather than simply soot into unwanted flowers. Soil manured the year before is best. If your soil is acid or neutral, then a dressing of garden lime will also be beneficial.
If your soil does not fall into this category, it does not mean you cannot grow Calabrese. You can provide feeds throughout the growing season – liquid feeds being best.
To grow good Calabrese, sow Calabrese in April through to July at latest. This is best done direct into the soil, for Calabrese - broccoli - is one member of the cabbage family that do not like to be transplanted. If you decide to sow seed for transplanting, then sow them in peat pots so that there is no root disturbance for the young broccoli plants when planted. If you grow in unit pots – do NOT use ericaceous compost for all members of the cabbage family need alkaline conditions.
If planting from small plants, ensure that the soil is well firmed around the base of the plant – pressing down rather than into the stem, to ensure firm roots without bruising the young stem.
Space the plants about 300 mm (12 in) apart for the highest yields. If you grow them closer - say, 200-225 mm (8-9 in) apart - the side shoots will be suppressed and smaller terminal shoots will mature all together, which is useful for freezing.
Calabrese needs to be fed and watered well – especially if you are growing specifically for freezing. Rapid growth is required for the best freezing of Calabrese. It is normally ready for cutting in about ten weeks after planting. Cut off the main central head - leave the main stalk and it will re-sprout to give further small heads, later on.
Feed with weakened liquid feed – Tomato food will do as well as any – but do not feed when the soil is dry. In any event the plants require to be watered to produce the growth.
As the broccoli head develops, it is a good idea in hot areas to break the leaves over the prized head. This will ensure a good green colour and prevent the sunlight from turning it yellow.
There are two distinct types of Calabrese, being the round headed type and another type having the head split into pyramidal clusters.
They are often referred to as Calabrese or Broccoli - being the round headed version – or ‘Romanesco’ being the pyramidal headed type. The latter is said to have the best taste - especially after freezing, but it is also a little more difficult to grow well. Best to start with the round headed form of Calabrese.
Calabrese is good for freezing as it retains its flavour well, but the sooner after harvesting that the process starts, the better.
The best varieties for freezing are ‘Green Comet’ and ‘Premium Crop’. Much depends upon your seed supplier. Most vegetable seed companies have their favourites.
Calabrese freezes well, retaining both its colour and flavour.
The soil for growing Calabrese needs to be alkaline - as with all Brassicas, and watering will be required throughout the summer - especially in dry conditions. They are best grown in an open sunny position. They are not as fussy as other members of the cabbage