The tough, bitter outer leaves of a radicchio are largely a waste of time but their true value is in protecting the dense hearts. These are highly sought after, so are often difficult to obtain. Look for them at the markets. They’re totally worth the effort.
Though technically a perennial it is usually grown as an annual. In warmer temperate climates, if the head is carefully cut from the roots in autumn, the roots may survive winter to regrow another head in the spring.
PLANTING
Sow seeds directly to the patch if conditions are mild/warm, otherwise propagate in a seed tray and then transplant to the patch when seedlings are 4 weeks old. Make sure to keep watering up to both seeds and seedlings – always in the morning – as young leafy greens are delicate to both the sun and snails/slugs.
WATERING
In ground: Water daily for the first 4 weeks and 3-4 times a week in the absence of rainfall thereafter. More frequent watering may be required during the warmer times of the year.
In Pots: Water daily while establishing and for the entirety of the warm season, otherwise every second day – after they are 4 weeks old – if growing during the cooler times of the year.
MAINTENANCE
When your plants are young it is often worthwhile to protect them with plastic collars to prevent snail and slug damage, particularly when conditions are very wet. To avoid exacerbating the issue, make sure to water in the morning rather than in the evening.
Mulch around your plants once they are settled into the patch, using pea straw, lucerne hay or sugar cane mulch to a depth of 3-5cm.
Feed your plants every 4 weeks with a liquid seaweed solution, but with something nitrogen heavy – fish fertiliser is ideal – once your plants are 10 weeks old, this helps to create denser hearts, which for us is the ultimate prize from Radicchio.
To achieve the characteristic red colouring and white heads, you will need to blanch your plants. Blanching excludes sunlight from the heads so that they lose their chlorophyll. Generally you need to start the blanching process 2 – 3 weeks before harvest. There are a couple of easy ways to do it; either by using its own leaves or by placing a pot over the plant.
HARVESTING
When planting from seed it will be approximately 8-10 weeks if you choose to harvest leaf by leaf, however it will be closer to 16 weeks if you are after a densely packed heart.
When growing as a perennial make sure to carefully cut at the base of the stem, just above the root zone.
TIP
Radicchio is a perennial plant that we grow as an annual. So if you are growing radicchio in more temperate climates and are not fussed about it occupying garden real estate, you can carefully cut it at the base of the stem leaving the roots intact to lie dormant in the winter. With a little luck you will get a new head shooting come spring time.
