Soil — How to Grow
Grow from sets in spring in the same way as standard onions — push into prepared, well-drained soil in rows, tip just showing. They tend to store slightly less well than brown onions so use within a few months of harvest. Harvest when foliage falls and turns dry; cure thoroughly before storing to avoid neck rot.
Space plants 10cm apart
Watch Out For
Companion Planting
Keep apart from
Regional Growing Guides
Uk
Sow
Feb, Mar, Apr
Harvest
Jul, Aug
Smoke — In the Kitchen
Red onion is a versatile vegetable with a distinctive sharpness and subtle sweetness that mellows beautifully when cooked. Raw, it has a crisp texture and a pungent, slightly spicy flavour that adds a fresh bite to salads and salsas. When exposed to heat, especially over an open flame or on a BBQ, red onion undergoes a transformation: its natural sugars caramelise, producing a rich, jammy texture and a deep, sweet flavour that complements smoky and savoury dishes. This makes it an ideal companion for grilled meats, fish, and even vegetarian options. When cooking red onion on the grill, it is best to slice it into thick rings or wedges to prevent it from falling apart. The heat softens the layers while the edges char slightly, adding complexity and a hint of smokiness. You can also skewer chunks for kebabs or wrap slices in foil with herbs and a splash of vinegar or olive oil to infuse extra flavour. Buying firm onions with smooth, dry skins ensures freshness. Avoid any with soft spots or sprouting as this indicates age and reduced quality. For storage, keep red onions in a cool, dark, and well-ventilated place away from potatoes, which can cause them to spoil faster. Once cut, wrap the onion tightly and refrigerate to maintain moisture and slow down oxidation. Proper storage will preserve their flavour and texture for several weeks, allowing you to enjoy their full potential in your everyday BBQ cooking.
Prep
Quarter through the root, or halve crosswise and grid-mark the cut face. Oil and season.
Cook
Halves cut-face-down over medium heat: 8–10 minutes — the cut face caramelises to an almost jammy texture. Great with balsamic glaze. Red onions are sweeter than white and respond brilliantly to the grill.









