Tips for Growing Romanesco Cauliflower in Pots

Romanesco is a worthy addition to any vegetable garden. The sophisticated member of the cabbage family is superbly flavored and nutritious. What makes it popular is not even the nutty taste and its crispy texture, but the striking apple green heads with numerous spiraling cone-shaped florets.

It simply looks like something from another planet. Leaves are large, dark green, and resemble those of cauliflower. If left to go to seed, it will bolt and produce small yellow flowers that are bitter in taste. This explains why Romanesco is harvested before the head has a chance to bloom.

Hailing from northern Italy, this vegetable was once grown exclusively around Rome, but it’s now a favorite in many regions, including the US. Romanesco cauliflower grows exceptionally well in temperate climates over the cooler months. Extreme heat or drought affects bud development.

Here are a few things to know about the Romanesco plant.

Common names	Romanesco Cauliflower, Romanesco Broccoli
Botanical name	Brassica oleracea (Botrytis group)
Plant type	Annual
Foliage color	Bright green
Size when mature	Height 18.0 – 24.0″ and 18.0 – 20.0″ Diameter
Sun exposure	Full sun, min 6 hours daily
Hardiness Zones	3a – 10b USDA
Soil pH	6.0 to 7.5
Growing Temp	40°F – 75°F
Days to Maturity	70-90
Growing difficulty	East to moderate

How to Grow Romanesco Cauliflower in Pots

I have successfully grown Romanesco in 5-gallon fabric containers. Although a little daunting, the experience is fulfilling, especially when you don’t have enough space. Here are tips that worked for me in growing Romanesco cauliflower in pots.

1. Sow indoors 

Romanesco is easy to grow in pots or gardens like normal broccoli or cauliflower. Even though it is a cool-season plant, it is best started 5-6 weeks before the last anticipated frost and transplanted into the garden in early spring. For fall planting, sow your seeds in late July or August.

While you can sow directly in the pots, I prefer using generous-sized module trays and soilless potting media for stronger healthy plants. Make sure to press the seeds one-half inch deep, and they will pop up in as little as one week. Once the seedlings appear, place the tray in bright light to encourage growth.

2. Use well-drained soil

Romanesco thrives in fertile loamy soils that drain well. Water standing at the root may cause root rot and other fungal infections. So it’s important to use well-drained soil when growing. The soil should be high in organic matter with a 6.0 to 7.5 pH. I prefer compost or well- rotted manure.

3. Keep the temperature cool 

As said, Romanesco broccoli grows best in cool weather. Start your earliest seedlings off under the protection of an unheated greenhouse or cold frame. Seedlings should be transplanted outside once the soil temperature is in the range of 40°F – 75°F.

4. Use pots with drainage

Water standing at the roots of the plants can cause root rot and other fungal problems. For successful container gardening, use pots with drainage holes. I recommend using fabric containers or breathable terracotta pots, as they also allow air to circulate the roots.

5. Harden the seedlings before transplanting

Leave them outside during the day and bring them under cover, gradually over a period of one to two weeks. Start with one hour, and you increase to about six hours as you near the transplanting day. This also helps in preventing the seedlings from becoming leggy.

6. Provide bright indirect light

Romanesco needs full sun to produce tasty edible heads. Ensure the plants get 6 to 8 hours of light per day. The vegetable will also grow well under a variety of artificial lamps, including LED or fluorescent. Plants that don’t get enough light may grow pale and leggy.

7. Fertilize accordingly

Romanesco are heavy feeder of nitrogen, potassium, and phosphorus. So, before you start, it’s always important to conduct a sail test, available through local university extensions. If the soil fertility is low, apply a balanced fertilizer as directed four weeks after transplanting. 

8. Water moderately

The Romanesco Cauliflower plant requires moderate levels of water. Always aim for consistent soil moisture. You don’t have to worry about frequent watering unless the weather is dry and hot. Lack of moisture outdoors can cause plants to bolt, making the vegetables unusable.

9. Apply mulch

Mulch can help grow Romanesco broccoli. The protection layer can moderate soil temperature during the cold winters, keep weeds under control, and conserve moisture. The plants will be better off with straw, shredded leaves, paper mulch, or newspaper.

10. Do not prune

Pruning is not recommended for Romanesco plants. The action can greatly reduce production and expose the plant to fungal infections. If they become too top-heavy as they grow, provide a stake for support.

Common pests and diseases

Like other plants in the cabbage family, Romanesco broccoli is susceptible to several pests, such as caterpillars, diamondback moth, cabbage root maggots, and cabbage looper. Regular inspection can help in early detection for appropriate treatment.

Without proper care, diseases such as blackleg, black rot, and clubroot can be a problem. Most pest and disease control is best achieved by a 3-year rotation. Do not plant the crops in the same soil or the same place consecutively. You may plant legume crops like beans and peas.

Harvesting and storing Romanesco cauliflower

Romanesco cauliflower is ready to harvest 75 to 90 days after transplanting. You need to cut the main head while it is still intact, and before the florets begin to spread apart and open. Keep it unwashed in a plastic bag in the crisper drawer of your refrigerator, and it will remain fresh for up to a week

This vegetable can also be blanched and frozen for later use. However, the earlier you eat it, the better the taste. I love the flavor when eaten raw or steamed. You can also sauté, roast, or boil it. Whatever method you choose to consume it, you will still benefit from tons of nutrients in this vegetable.