[data-breadcrumbs] { opacity: 1 !important; visibility: visible !important; } @media screen and (max-width: 767px) { [data-breadcrumbs] [data-breadcrumb-middle] { display: inline-flex !important; } [data-breadcrumbs] [data-breadcrumb-ellipsis] { display: none !important; } }

Heat Treated Rosanna Onion Sets

Name: Heat Treated Rosanna Onion Sets
Brand: DT Brown
SKU: 53098
Price: 6.95 GBP
Availability: InStock

Botanical Name: Allium cepa

250g pack (approx 80 sets)SKU: 53098

From: 12/03/2027

£6.95

Buy with confidence - quality guarantee

High germination rates

Expert growing support available

DescriptionDetailsGrow InPlanting CalendarDelivery

Heat-treated Rosanna onion sets are a must-have for any vegetable garden or allotment. Bred specifically for the UK climate, the Rosanna has performed exceptionally well at recent trials. This modern hybrid onion is crossed with the Rose de Roscoff – a well-known heritage variety that was once sold door-to-door by traditional French onion sellers.

Boasting a unique sweet and fruity taste, Rosannas are impressive globe-shaped onion plants marked by a characteristic pink blush. This colour continues once peeled, revealing stunning rosy hues running right through the layers. With their melt-in-the-mouth flavour, these gourmet onions are perfect for eating raw in salads or adding depth to cooked dishes.

Our Rosanna onion sets are carefully heat-treated before despatch – an entirely natural process which takes several months. This ensures rapid establishment and growth, resulting in higher yields. It also virtually eliminates the risk of the onions prematurely running to seed or 'bolting'.

All of our onions are certified disease- and virus-free. Plant these particular onion sets outdoors in March and April and enjoy a bountiful home-grown harvest from August to September. 250g pack contains around 70 sets for planting.

Key information

Botanical Name: Allium cepa

Genus: Onion

Recommended growing locations.

Allotment / Veg Patch

Container

Raised Bed

J Jan F Feb M Mar A Apr M May J Jun J Jul A Aug S Sep O Oct N Nov D Dec

Sow Indoors

J Jan F Feb M Mar A Apr M May J Jun J Jul A Aug S Sep O Oct N Nov D Dec

Sow Outside

J Jan F Feb M Mar A Apr M May J Jun J Jul A Aug S Sep O Oct N Nov D Dec

Flowers / Harvest

J Jan F Feb M Mar A Apr M May J Jun J Jul A Aug S Sep O Oct N Nov D Dec

Hassle-Free Delivery

Looking for a hassle-free way to get your gardening essentials? Look no further than DT Brown! We know how important your garden is to you, and want you to be able to stock up on everything you need. All our delivery charges will automatically appear in your shopping basket.

1

Seed Only Orders

£2.95 delivery charge

2

Non-Seed Items

£6.95 delivery charge

3

Combined Orders

£7.95 delivery charge (e.g. seeds and plants)

Heat Treated Rosanna Onion Sets

£6.95

FAQs

Want to know even more about our Rosanna Onion Sets? We answer your questions here.

What are heat-treated onion sets?

Heat-treated onion sets are small, immature onion bulbs that have undergone a carefully controlled natural heating process over several months. This treatment triggers the plant's flowering cycle early, effectively preventing the onions from bolting when planted in your garden. The result is more reliable crops, faster establishment, stronger growth and higher yields.

How to grow Rosanna onion sets?

Plant Rosanna onion sets from March to April in well-prepared, fertile soil with good drainage. Push each set gently into the soil so just the tip shows above the surface, spacing them 10 cm apart in rows 25-30 cm apart. Choose a sunny position and firm the soil around each set. Keep the area weed-free and water during dry spells.

How do you harvest and store your Rosanna onions?

Harvest Rosanna onions when the foliage turns yellow and falls over naturally, in July to August. Gently lift the bulbs with a fork on a dry day and lay them out to dry for a couple of weeks in a sunny, well-ventilated spot or under cover if rain threatens. Once the skins are papery and the necks have dried completely, trim off any remaining foliage and store in nets, trays or sacks in a cool, dry, frost-free place with good air circulation.