Spring Onion
Allium fistulosum
Spring onions are one of the quickest and easiest salad crops, ready to harvest just 8–12 weeks after sowing. They take up very little space and can be tucked in between slower-growing crops, making them perfect for intensive allotment gardening. Sow seed thinly in drills 1cm deep from March to September for a near-continuous harvest from late spring to autumn. Successional sowing every 3–4 weeks ensures you never run out. Hardy varieties like 'White Lisbon Winter Hardy' can be sown in September and October to overwinter, providing the earliest spring harvest. They grow happily in containers, window boxes, and grow bags. No thinning is needed — simply pull individual onions as required, or harvest whole clusters. They prefer fertile, moisture-retentive soil in full sun or light shade. Water in dry weather to prevent the bulbs becoming tough and overly pungent. Japanese bunching onions (A. fistulosum) are a perennial alternative that can be harvested repeatedly. 'Performer' is excellent for summer crops; 'Guardsman' for its upright, uniform growth; and 'North Holland Blood Red' for striking red-skinned bulbs.
Plan where to grow Spring Onion using our vegetable garden planner.
When to Sow Spring Onion
Sow spring onion in March, April, May, June, July, August, September, October.
Time to Harvest Spring Onion
Expect to harvest approximately 2 months after sowing.
Expected Yield
Very quick crop; a 1m row produces 30–40 spring onions in 8–12 weeks.
Growing Tips
Sow successionally every 3–4 weeks for continuous harvest
Common Problems with Spring Onion
Onion fly
Small white maggots bore into the base of the bulb, causing yellowing and wilting leaves. The flies are attracted by the scent of bruised foliage, so avoid thinning (which isn't needed for spring onions anyway). Cover with enviromesh from sowing to harvest to prevent egg-laying. Grow alongside carrots — the onion scent deters carrot fly in return.
Bolting (running to seed)
Spring onions sown too early in cold conditions, or those subjected to sudden temperature fluctuations, may bolt — sending up a flower stalk instead of forming a usable bulb. Sow at the right time for your area, and use bolt-resistant varieties like 'Performer' for early sowings. Bolted plants are still edible but tougher.
Downy mildew
Leaves develop grey-purple fuzzy patches and turn yellow from the tips down, especially in wet, humid weather. Avoid overhead watering, ensure good spacing for air circulation, and remove affected foliage. Rotate allium crops annually. Worst in cool, damp autumns on overwintering crops.
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Cherry Tomato
Solanum lycopersicum var. cerasiforme
Cherry tomatoes are one of the most rewarding crops for UK allotment growers. These small, sweet fruits ripen reliably even in cooler summers, producing heavy trusses from July right through to October. They thrive in grow bags, pots, or directly in the ground, making them versatile for any plot size. Pinch out side shoots regularly on cordon varieties to channel energy into fruit production. Bush varieties like 'Tumbling Tom' need no training and work brilliantly in hanging baskets. Feed weekly with a high-potash tomato feed once the first fruits set. The key to great flavour is letting them ripen fully on the vine rather than picking early.
Beefsteak Tomato
Solanum lycopersicum
Beefsteak tomatoes produce the large, meaty fruits that are perfect for slicing into sandwiches and burgers. They need a long growing season in the UK, so starting seeds early under cover is essential. These are almost always grown as cordons — train them up a single stem, removing side shoots weekly. Each truss produces fewer but much larger fruits than cherry types, often weighing 200–500g each. They benefit from greenhouse growing in cooler regions, though sheltered outdoor spots in the south can produce good results. Consistent watering is critical; irregular watering causes blossom end rot and fruit splitting. Stop the plant at 4–5 trusses to ensure fruits ripen before autumn.
Nantes Carrot
Daucus carota
Nantes carrots are the gold standard for flavour — sweet, crisp, and cylindrical with a smooth skin that barely needs peeling. They perform well in most UK soils but prefer light, stone-free ground to grow straight. If your soil is heavy clay, grow them in raised beds or deep containers filled with sandy compost. Sow thinly to avoid the need for heavy thinning, which attracts carrot fly. Cover rows with fine mesh or enviromesh as a physical barrier against carrot fly — this is far more reliable than companion planting alone. Successional sowing from March to July gives you carrots from June through to winter. Late sowings can be left in the ground over winter under a thick mulch of straw.
Butterhead Lettuce
Lactuca sativa
Butterhead lettuce produces soft, rounded heads with tender, buttery-textured leaves that melt in the mouth. It's one of the quickest salad crops to grow — ready in as little as 8 weeks from sowing. Unlike iceberg types, butterheads tolerate partial shade and are less likely to bolt in warm spells. Sow small batches every 2–3 weeks from March to September for a continuous supply. They work well as an intercrop between slower-growing vegetables like brassicas and leeks. Water consistently but avoid wetting the leaves to reduce the risk of grey mould. 'All the Year Round' is the classic UK variety and lives up to its name, performing well in almost every season.