How to grow Calabrese

How to grow Calabrese

Calabrese is one of the most rewarding members of the brassica tribe you can grow. Chock full of cancer-fighting compounds ready for devouring within a few short months, it’s a crop that works hard to earn its place on the plot. If you’re wondering what calabrese is, it’s sold as broccoli in the supermarkets – the firm bright green heads that are delicious lightly steamed, stir-fried or made into a rich soup with blue cheese.

This misnaming has given rise to some confusion between calabrese and ‘true’ broccoli – a sprouting vegetable that’s enjoyed very early on in the year when pickings on the plot are otherwise thin. True broccoli overwinters while calabrese is sown, grown and harvested in the same year, completing its useful life cycle within four to five months, and often quicker than this.

Calabrese broccoli needs a rich, firm soil that isn’t acidic. You will need to ensure there is minimal root disturbance, which means sowing directly where it is to grow, or starting seedlings off in modules and pots, rather than transplanting. During the growing season, broccoli plants demand careful watering and a weed-free patch.

Protection against some of calabrese broccoli’s biggest pests, notably marauding pigeons and the cabbage white butterfly, is also likely to be necessary. Don’t be put off if all this sounds like too much fuss – despite appearances calabrese is still a relatively easy crop to grow and given these few precautions you’ll be picking good, solid heads of tightly-closed flower buds throughout late summer and autumn and cooking into tasty broccoli recipes before you know it.

Where does broccoli grow best?

Pick a sunny position on the vegetable plot for your calabrese. It is important to practice strict crop rotation to avoid potential pest and disease problems, as well as making the best use of your soil. Do not plant your plants where other members of the calabrese broccoli family, brassicas such as cabbage and Brussels sprouts, have grown in the past two years. If possible, follow the plants on from legumes such as peas.

Like all brassicas, calabrese broccoli prefers a firm, loamy soil that is full of nutrients. Prepare the ground the autumn or winter before sowing by digging it over then adding organic matter – about a barrow load of garden compost, leaf mould or manure per square metre should do the trick. Allow the worms to draw this into the ground over winter, before forking over the area the following spring.

If your soil is in any way acidic, you will need to apply some garden lime at this point. Add at least 100g per square metre, or considerably more if your soil has a particularly low pH. It is hard to add too much lime for your calabrese crop, so err on the side of excess if in doubt. The level should be at least pH 7.5 – that’s just above neutral.

Around one week before sowing or planting out, add a final boost of nutrients to the soil by sprinkling over some blood, fish and bonemeal – a general-purpose organic fertiliser that will give your young broccoli plants a strong start.

Growing broccoli in a greenhouse

Calabrese may be sown directly where it is to grow outdoors, or started off under cover in modules or pots. These broccoli plants hate root disturbance and sowing in this way reduces this risk. Sow directly in rows placed 45-60cm apart – the larger spacing will give bigger heads at harvest time.

Draw drills into finely raked soil approximately 1cm deep and sow the seed very thinly. Alternatively, station sow by dropping a few seeds every 25cm, which will allow an intercrop of quick-growing radishes, spinach or salads before the calabrese needs the extra room to start producing broccoli heads. Cover the seeds back over and moisten the rows using a watering can fitted with a rose.

To sow under protection into modules, drop a couple of calabrese seeds into each cell and cover over with 1cm of compost. Water from the base of the trays, so that the moisture is drawn up from below without unsettling the newly sown seeds. Sowings under glass or plastic can be made as early as March, while those outside should begin in April or a few weeks earlier given the added warmth and protection of a cloche. Sowing a small quantity every few weeks up to mid-June can be helpful in extending the broccoli harvesting season.

Seedlings should emerge within about 10 days at which point direct-sown crops may be thinned to an initial spacing of one plant every 10-25cm. Thin young calabrese plants further once they are 5-7cm high to leave one every 50cm. Try to leave the biggest, healthiest seedlings in place each time to give your broccoli crop the best possible start.

Module-sown calabrese can be potted on into their own individual 7-10cm plastic pots when they are big enough. Take extreme care not to disturb the roots – slide the seedlings out of their modules very gently and have pre-prepared pots ready to receive them. Fill containers with compost, making a hole that is the same size as the module’s rootball. When the young broccoli plants are about 10cm high and have a few adult leaves they can be transferred outside. This will be in June or early July. Set the brassicas in rows 45-60cm apart, leaving 50cm between plants within the row.

How to grow broccoli indoors

You may want to grow broccoli from scraps of your food waste, but this would be a fun project, rather than to get a productive return for your efforts. Gardeners hungry for a quick result from their calabrese should consider growing microgreens rather than for broccoli heads. Loved by top chefs the world over, these tender leaves add sparkle and flavour to sandwiches and salads, or as a garnish to soups and hot dishes.

For gardeners growing in limited space, and searching for ways to grow broccoli in pots indoors, this is a good solution. Microgreens, also called micro-leaves, are simply seedlings harvested at their first leaf stage. The time to harvest is astonishingly quick – as fast as five days and rarely longer than two weeks. The cress and mustard you probably grew as a child are microgreens.

The young seedlings of calabrese and broccoli have a gentle, peppery flavour that goes well with egg dishes or fish. Don’t waste expensive calabrese seed to grow your microgreens – instead buy purpose-sold broccoli microgreen seeds. Add a double-layer of kitchen paper into the bottom of an old food container, mist with water and then sow fairly thickly. Place the container on a light windowsill and keep moist. Harvest by snipping the greens at their base.