How to Grow Radicchio (Complete Care Guide)

So, you want to grow radicchio in your garden.

This bitter, complex vegetable can be used as a lettuce substitute in your salad when you’re getting tired of eating the same old same old.

Although it’s not as popular in the US as it is in other countries, it still offers a flavor that becomes a new addiction for many people.

It can even be used in soups, sauces, or added as a flavor complement to balance out some sweeter vegetables.

We’ll cover everything you need to know about growing, planting, and caring for radicchio.

Ready to grow some radicchio? Let’s rock.

Quick care guide: Radicchio

Plant type	Perennial (warmer zones), annual (colder zones)
Origin	Italy
Scientific name	Cichorium intybus
Other names	Chicory, Italian chicory.
Soil type	Well-draining, loose
Soil pH	7.5-8 (slightly alkaline)
Sunlight requirement	Full sun
Bloom season	Spring, summer
Colors	Pink, burgundy, purple, white, green
Max height	12 inches
Max width	18 inches
Low temperature	30F
High temperature	90F
Ideal temperature range	60-70F
Humidity	Very high
Watering requirements	Often, keep soil wet, but not waterlogged
Fertilizer requirements	Medium
Fertilizer NPK	5-5-5
Days until germination	1-3 weeks
Days until bloom	60-70 days
Speed of growth	Very fast
Hardiness zones	5, 6, 7, 8, 9, 10
Plant depth	0.25 inches
Plant spacing	8-12 inches
Propagation	Seeds, cuttings
Common pests	Aphids, mealybugs, spider mites
Common diseases	Root rot, bulb rot, powdery mildew, botrytis, anthracnose
Indoor plant	Yes (when sowing only)
Outdoor plant	Yes
Grown in container	Yes
Flowering plant	Yes
Beginner friendly	Yes
Care level	Medium
Uses	Cooking, recipes, soups, salads, edible vegetable

What’s radicchio?

Radicchio looks like miniature red cabbage. Many people don’t know the proper name for it or even know where it comes from, as it’s not nearly as popular as mainstream vegetables.

It has a bitter taste and is surely distinct from other veggies. Since many people here in the US prefer sweeter veggies, it makes sense that bitter greens don’t top the list of favorites.

But in other parts of the world, this plant is cherished for its full flavor. The flavor is herbal and bitter, but tasty to add some oomph to your food. Italy is a prime example. This plant is grown to an art in their country.

Origins

Radicchio is also known as Italian chicory and comes from the chicory plant.

The veggie is part of the Asteraceae plant family which also includes sunflowers.

Even though the plants are far from similar, they’re still in the same family because of their characteristics and flowering phenotype. The plant grows natively all over the world in countries like Africa, Europe, Asia, Australia, and even parts of America.

Why is it so expensive?

Producing traditional radicchio requires a lot of work and patience to grow.

The process of growing this plant is difficult. it’s been refined over many decades to get the bitter, rich flavors we can extract from it today.

Italians are given the credit for their hard work over many decades for the plant we can simply buy at the supermarket today.

Types of radicchio

Raddicchio freshly grown. — Bitter and crunchy.

Many varieties and new ones are being discovered.

They’re often named after the area they were found in (the majority in Itlay), which gives them those heritage-rich names.

In the United States, the most common type of radicchio is Chioggia which people identify by its red leaves and spherical shape- like a small red cabbage (but it’s not).

This is a beet, not a cabbage.

The common types are green heads and red heads. The red headings will turn color in cooler weather.

When blanched, they may transform into brown heads before harvest. There is also differently shaped radicchio, such as Belgian or Treviso that have elongated shapes.

Some types are looser, such as Radichetta.

Bel Fiore, Chioggia, Indigo, Red Verona, Palla Rossa, Red Treviso, and Rosso di Chioggia are all popular types that are commonly grown commercially or in the yard.

Hardiness zone

The best hardiness zone for growing radicchio is zones 4-10.

This particular veggie needs a warmer temperature and doesn’t have cold tolerance. It’s also quite finicky and sensitive to cold snaps so keeping temps stable is key.

The hardiness zone of where you plant it matters and is the foundation of a garden that produces radicchio efficiently.

When to plant

The best time to plant is either in the early spring or fall. This depends on the date of the last frost in your area. You want to time the sowing so that you can harvest before the frost comes and wipes it out.

If you’re in a higher hardiness zone, you should be OK.

But colder zones will need to focus on timing it properly or provide some other kind of artificial way to heat the plants (greenhouse planting, growing indoors, row covers, mulch, cold frames, etc.)

How to propagate radicchio

There are two main ways to propagate this plant.

It can be done by direct sowing from seeds or transplants (cuttings). Here we’ll cover the process of doing both propagation techniques.

From seed

Starting from seed is the most popular method for advanced growers.

Utilizing the seed that was previously grown in your lineage ensures that you get exactly what you expect.

But for beginners, it’s not recommended because it takes a lot longer and can be disappointing.

If you’ve never grown radicchio before, I suggest starting cuttings or transplants until you have some experience under your belt.

For those that want a bit of a challenge and are up for it, radicchio seeds can be sown in the spring around 3 weeks before the last frost date. Look up the average last frost and sow the seeds accordingly.

Depending on the specific strain you’re growing, you’ll need to plan ahead of time so that it becomes ready to harvest to decide when to plant.

This is important if you’re growing in an area that has cold temps in the winter. If you’re in a mild area, it’s not as important to time it.

But for the best chance of harvest, you should plant accordingly based on time until frost.

If your cultivar takes longer to harvest, plant earlier.
If it’s an early bloomer, then plant it later.

Average cultivars of radicchio will be ready for harvest in about 4-6 weeks so you can use this ETA if you don’t know what type of radicchio you have.

When planting from seed, plant as many as possible at the same time. Radicchio won’t have a high germination rate, so you can maximize your yield by quantity over quality. Each seed can be planted together with others in a large container.

Space each seed a few cm apart and 0.25” deep to let them grow.

As they sprout, pluck the smaller seedlings to allow more space and nutrients for the larger ones to thrive.

Some gardeners will plant in the fall, which allows the seeds to develop after the first frost in your area.

Growing indoors

The seeds can be sown indoors using a seed starter with a nutrient-rich starting medium.

Each seed should be planted 1/4” in depth and 1-2 seeds per square.

Keep the sprouts wet with the dome cover. Transplant after they grow their first set of true leaves. Thin accordingly.

From seedlings/transplants

This is the recommended method for people new to growing radicchio. Starting from a small transplant saves you time and guarantees germination.

You also don’t have to deal with the work due to planting seeds, watering them, and hoping that you see those small green sprouts pop out of the dirt. Easy peasy.

Radicchio can be hard to find in your local nursery, so you’ll want to call around to make sure they have it.

When you’re there, ask the expert for some tips and the specific cultivar you’re growing. Specialty nurseries may have radicchio in stock.

When you take your transplants home, plant them based on the average frost date in your region. Transplant the seedlings in the spring or the fall, depending on your hardiness zone.

You can even start the seedlings indoors, then slowly acclimate them to the outdoors. They can tolerate a small cold snap here and there, but don’t let them stay in the cold for extended periods.

Taking it outdoors for an hour or so each day and then slowly increasing the time outside can help harden them off.

After a week or so of hardening to the outdoor elements, you can transplant them to their new home in the garden.

How to grow radicho

Here we’ll cover the basic requirements for the best yield. You’ll find answers to the most commonly asked questions here in this section.

Remember that the process will vary depending on your hardiness zone.

Location

Choose a location that has either full or partial sun for the best yield possible.

Radicchio likes full sun in warm weather with moderate humidity for best results.

Some partial shade helps when the team-tires are too high in higher hardiness zones that the plant can’t tolerate. This will help the plant not burn in the sun. 6-8 hours is all that’s needed for sufficient growth.

Sunlight

The more sunlight the plant is exposed to, the more color it’ll produce.

Depending on the cultivar you’re growing, sunlight UV rays will make the plant turn from green to red, while others will stay green.

Don’t be afraid if your radicchio stays green or even only slightly turns red, this may be normal based on the strain you’re growing.

Soil type

Radicchio prefers well-draining, nutritious soil that’s high in organic content.

Some mulch or compost also works well to supplement the nutritional profile of the soil. If you don’t know the metric of your soil, you can use a soil tester to find out.

Moist soil also helps prevent some of the bitter flavors in the dish. Radicchio tolerates a variety of soil types but grows best with loamy, fertile soil. Moisture retaining and well-draining soils are ideal.

You can add some compost to help improve drainage. Mulch can also be used to help keep weeds out and retain water in the soil. Organic mulch or leaves both works.

Soil pH

Radicchio prefers soils that are slightly alkaline, not acidic. Aim for soil that has a pH of 7.5-8 for best results.

You can add supplements to help raise the pH such as limestone powder or wood ash. Use organic amendments to keep your veggies organic certified.

If you’re growing in a container, use an organic, well-draining potting mix rather than garden soil.
If you’re growing outdoors, use high-quality garden soil supplemented with compost.

Depth

When starting from seed, place each seed ¼ inch deep.

There’s no need to press down on the soil after you backfill it. The seed will sprout by itself and poke its head through the dark soil to make your day after germination. Just give it some time and TLC.

Spacing

Space each plant at least a few cm apart to prevent trapping moisture and humidity problems later down the line. The more space you provide, the easier it is for moisture to escape.

If you’re growing a dense plot of radicchio, consider adding ample space between each plant in rows.

Watering

Watering radicchio is easy. The soil just needs to be kept wet and moist at all times. It should never be waterlogged and should never be completely dry.

You don’t need to follow any “let it dry out” rule here. Keep it wet, friends.

Temperature

Keep temps stable for best growth. Temperature dips below 20F should be OK, but don’t let it keep those cold conditions for an extended period.

This is a cold-loving plant and grows well with similar veggies like cauliflower and broccoli. Consider companion planting for more goodies in your garden.

If you’re in a colder zone, consider doing the following to help keep your radicchio warm in the wintertime:

Add a blanket of mulch to protect the root system
Move the plant indoors or into a greenhouse if it’s planted in a pot
Build a cold frame (DIY frames are easy to construct)
For those in warmer climates, you should be fine just keeping it outdoors during the winter.

Did you know that radicchio tolerates cold, but not heat? That’s right. They like the COLD.

Temperature spikes will damage the plant and it’s important to keep them below 80F for best results. Anything above 75F will cause your plant to start bolting.

The plant seeds will sprout and the plant will produce an extremely bitter taste. For most people, boiled radicchio is too bitter to eat or use in recipes.

The ideal zone is warm, but NOT hot. This lets you grow it when you want rather than letting it wilt by the summer heat.

Western states in the north are the ideal planting location. But for the rest of us, we’ll have to deal with temp swings and time our planting season.

Humidity

Radicchio likes humid environments, but not allowing proper air flow will lead to fungal problems and rot. You can help improve air flow and reduce humidity by pruning the leaves and eating them, or spacing your plants. Keep the humidity around 98% or higher.

If you’re having trouble keeping it this high, use a humidity dish or drip system.

Plant food

Radicchio fertilizer should be an organic blood meal. They benefit from nitrogen-rich plant foods a few months after being planted. Look at the NPK rating and opt for a 12-0-0 fertilizer.

Harvesting

Radicchio is ready to harvest anytime. The leaf heads can be collected and ready to be cut when they’re firm and not so soft.

This usually happens around 60 days of planting. Use a sterile pruner and cut the plant right at the soil line. The entire plant should be cut with nothing left behind.

The best time to harvest is when they’re still young so they don’t turn too bitter.

If you wait past the harvest period, the heads will start flowering by growing a flowering stem.

The core develops and will lead to flowering (bolting) if you don’t harvest them at the right time. This can lead to extremely bitter flavored radicchio and most people will discard them at this point.

You shouldn’t let them bolt unless you plan on propagating them and regrowing them.

Storage

After harvest, place the heads in the fridge in an airtight container. They last about 3 weeks in the cold. They can be used for recipes for even up to 3 weeks, plus will hold their flavor.

Best uses

Radicchio can be used for a variety of dishes, especially when a little “kick” is needed.

Not everyone will enjoy the bitter taste of radicchio, but for those that are a little more daring, this can be used as a simple veggie or cooked into a complex dish.

The bitterness can be controlled and balanced with some other sweeter foods or dressings. Walnuts, honey, berries, and other basic condiments can be used to help sweeten it up.

Radicchio can be used for a variety of recipes. The bitterness can be alleviated by mixing with some balsamic vinegar, butter, cheese, lemon, salami, shell beans, etc. It’s commonly used in salads or paired with fruit, potato, or even seafood. Radicchio can be eaten raw or cooked with the individual leaves or entire head.

Olive oil and salt with radicchio is a simple and no-cooking required side dish that can be prepped in just a few minutes.

Raw leaves blended with some mild lettuce or chunks of chicken can be used to stir up a tasty salad. Heads of radicchio can be used to bake or sauté for pasta, legumes, rice dishes, or soups.

Collecting seeds

Seeds can be harvested from the flowering shoots after the core develops. You can use these seeds to regrow the plant for future harvests.

Bolting

When you don’t harvest them on time, radicchio will develop the core and flowering stem, which will make it bolt. The only reason to do this is for propagation purposes.

You can harvest the seeds, then plant them for continued yields next season. Some bolt-resistant varieties stop bolting altogether.

Blanching

Blanching, also known as forcing, helps benefit the radicchio with some more flavor.

Since this plant is already biter by default, giving it a more unique flavor by blanching helps. It’s already a lot of work to produce it, so why not maximize the quality of each crop?

Blanching is already commonly practiced for other crops like celery to help sweeten the flavor. Radicchio that’s blanched will produce more colorful fruit and a complex flavoring.

The process is as follows:

Don’t harvest and leave radicchio in the soil after a hard freeze with the outer leaves tied around the heads of each plant
If tying isn’t an option, you can cover each radicchio plant with a container or use straw mulch to cover them
Harvest and pull out the outer leaves to reveal the tender, softer leaves on the inside
Blanching blocks sunlight from reaching the plant, which stops photosynthesis. This produces a plant that’s softer and sweeter.

How to regrow radicchio

You can regrow radicchio by using the seeds harvested after it bolts.

The seeds can be collected from the flowering stems that form from the core when it develops without harvest. Save the seeds and replant them to propagate your radicchio strain.

Follow the steps listed above for a detailed step-by-step guide on regrowing it.

Radicchio pests

This plant is susceptible to a variety of different insects that’ll gladly feed on the heads. The most common bugs are listed below with some basic ways to get rid of them.

Aphids will drain the life out of your plants by using their piercing mouthpieces to extract the plant juice. These are commonly found in the garden on a variety of different plants. They can be controlled by hose spray, horticultural oils, and exclusion.

Slugs and snails will chew holes in the leaves. They come out at night to munch on your plant and will leave behind a trail of slime. If your local environment is too damp, you may have a snail problem. Remove them by handpicking at night or using a beer trap.

Leafminers will bore holes in the leaves which leave behind random, veiny lines that run through the plant. These are easy to see and you’ll notice black and yellow flies. The larvae are responsible for the damage to the plant leaves and look like small yellow worms. Prune off any affected foliage.

Flea beetles are jumping beetles that will eat the leaves of your plant. They’re responsible for transmitting disease between plants. Avoid flea beetles by rotating crops properly.

Loopers are green worms that have a stripe on the sides of their body. They eat through radicchio heads. Use a worm killer and prune off any damaged foliage. You can also use row covers to keep larger pests off your radicchio.

Radicchio diseases

Alternaria leaf spot is the main culprit of radicchio.

This may cause brown or white spots to appear on the leaf surfaces, which can cause wilt or damage. Prune off any damaged parts and avoid overwatering. Provide plenty of air circulation to prevent rot or fungal problems.

Downy mildew is a fungus that forms white/gray patches on the leaves. You’ll first notice them on the underside of the leaves by seeing these patches.

Proper crop rotting will help prevent fungal problems in general. You can also water the stem, not directly overhead to stop trapping humidity. Space your radicchio plants correctly to allow proper dissipation of trapped humidity and dry out wet plants.

Black rot is caused by bacteria that grow in humid conditions. The leaves will show orange V-shaped lesions that spawn on the edges of the plant. The leaves will eventually wilt and fall off the plant. Rotate crops and keep humidity low to prevent this from occurring.

Damping off occurs when growing radicchio from seed. The seedling will wilt and then die nearly instantly. The culprit behind this is a fungus that grows when moisture is high with warmer temperatures above 68F. Avoid wet soil and decrease nitrogen in the soil’s profile.

Provide proper coruscation and avoid overcrowding by allowing the right amount of space.

The majority of problems can be prevented by keeping humidity low and allowing plenty of space between each radicchio plant. Don’t let them suffocate each other and keep the leaves pruned so they can dry out.