Onion Sets

Growing onions is a rewarding endeavour. Choose a sunny location with well-drained soil. Plant onion sets or seeds, ensuring proper spacing. Keep the soil consistently moist during the growing season. Onions thrive with nitrogen-rich fertiliser. Harvest when the tops have fallen over and dried. Cure onions in a dry, well-ventilated area before storage. With patience and care, you'll enjoy homegrown onions in various sizes and flavours.

  • Wide variety of delicious onions for sale
  • Perfect for pots and containers
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Onion Sets
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Onion Sets FAQs

Take a look at some of the frequently asked questions we receive from those looking to buy Onion Sets in the UK. You can contact our Customer Service Team or browse our general FAQs for further advice.

What is an onion set?

An onion set is a small, immature onion bulb that has been grown from seed and then harvested before it reaches full maturity. These small bulbs are typically sold for planting purposes and are used to grow onions in home gardens. Onion sets are advantageous because they offer a head start in the growing process, allowing gardeners to bypass the early stages of seed germination and seedling growth. They are planted directly into the soil in the garden, where they will develop into fully grown onions over the course of the growing season. Onion sets are available in various sizes and varieties, allowing gardeners to choose the best option for their growing conditions and culinary preferences.

What month do you plant onion sets?

Onion sets are typically planted in the UK in early spring, usually around March or April. This timing allows the sets to establish themselves before the warmer months, leading to better bulb development. It's essential to avoid planting onion sets too early in the winter, as they may not survive the colder temperatures. Additionally, planting too late in the spring may result in smaller bulbs. By planting onion sets in the early spring, you can ensure a successful harvest later in the year.

How many onions grow from one set?

From a single onion set, you can typically expect to grow one onion bulb. However, each bulb can produce multiple individual onion cloves or segments, which can be separated and planted to grow additional onion plants. Therefore, while one onion set yields one mature bulb, it can potentially result in multiple onions if the cloves are separated and planted individually.

How do I know when onions are ready to harvest?

Onions are ready to harvest when the tops begin to turn yellow and fall over. This typically occurs in late summer or early autumn, depending on when they were planted. As the onion tops start to dry and bend over, it indicates that the bulbs have stopped growing and are ready for harvesting. Additionally, you can gently push back the soil around the bulb to check if the outer skin has begun to dry and become papery. Once the majority of the tops have fallen over and the outer skin is dry, it's time to harvest the onions.

Do onions regrow after harvest?

No, onions do not regrow after harvest. Once onions are harvested, they do not produce new growth from the bulb. However, some onions may produce small bulblets or offsets around the base of the bulb after harvest. These bulblets can be replanted to grow new onion plants, but they will take time to mature into fully grown onions. Additionally, if you leave some onions in the ground and allow them to overwinter, they may produce flower stalks and develop seeds, which can be collected and planted to grow new onions in the following season. Overall, while onions do not regrow from the harvested bulb itself, they can produce new plants through bulblets or seeds.

Where can you grow Onion Sets?

Onion sets can be grown in various areas of your garden, offering flexibility in design and landscaping. They thrive in well-drained soil with plenty of sunlight, making garden beds or raised beds ideal locations for planting. Additionally, onion sets can be grown in containers or pots, making them suitable for small spaces or urban gardens. It's important to ensure that the soil is loose and well-aerated to allow for proper bulb development. With proper care and attention to soil quality and sunlight exposure, onion sets can flourish in a variety of garden settings, providing a bountiful harvest of flavorful bulbs.

Why Buy Onion Sets from Marshalls?

  • Our customers are supported by a team of experts dedicated to providing valuable advice. You can also use our growing guides, backed by 70 years of experience, to get the best results from your onion sets.
  • You can contact us six days a week – including bank holidays – to discuss our products and services or to chat about all things gardening.
  • We pride ourselves on offering fast delivery on all orders, with any 'in stock' plants and seeds sent out within three working days. We're green-fingered in more ways than one, too, thanks to our fully recyclable packaging.
  • We won second place at the 2022 Great British Growing Awards for Best Online Retailer.
  • Thousands of five-star reviews on Feefo and a 100% satisfaction guarantee on all our products show that we're a company you can trust.