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SeedStepsYour vegetable garden, one step at a time.My gardenRed Baron brings colour to the onion bed. Follow growing from seed or sets to a dry bulb, with separate source context for the variety, Dutch sowing guidance and general care.
This image was created with AI from described plant characteristics and growing advice. It shows a possible situation and is not a photograph of a verified cultivar.
This growing advice helps you choose. Your variety, growth stage, weather and conditions in your space determine the actual timing.
Start under cover in a cool, bright position · Onion
February–March for seed-grown onionsSow lightly in modules or a seed tray and grow on steadily.
Onion sets and seed-grown onions are different starting routes. Bunching and spring onions are generally harvested young.
Royal Horticultural Society · RHS — ui kweken ↗Soort- of productgebonden bron; buitenlandse perioden zijn geen vaste Nederlandse zaaidatum.
University of Minnesota Extension · UMN Extension — ui in de moestuin ↗Soort- of productgebonden bron; buitenlandse perioden zijn geen vaste Nederlandse zaaidatum.
Guideline periods for the Netherlands and Flanders. Check the variety, available light, soil and measured temperatures. Greenhouse heating does not guarantee enough winter light.
The source context and any limitations are in the background information at the bottom.
Compare with another varietyThe options below belong to the plant. From these, choose the method that suits your variety's growth habit.
This image was created with AI from described plant characteristics and growing advice. It shows a possible situation and is not a photograph of a verified cultivar.
Small planting bulbs make an accessible start. The tip stays visible and the root base gets loose soil.
For a simple start and a batch of storage onions.
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This image was created with AI from described plant characteristics and growing advice. It shows a possible situation and is not a photograph of a verified cultivar.
Sowing opens more choice but needs time for young shoots. Start timing must suit variety and intended planting position.
For anyone following the whole process with a suitable seed-grown variety.
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This image was created with AI from described plant characteristics and growing advice. It shows a possible situation and is not a photograph of a verified cultivar.
Onions can grow in a broad container if every bulb has enough room. A container makes weeding easy but needs more frequent moisture checks.
For a sunny balcony or patio and a limited stored crop.
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This image was created with AI from described plant characteristics and growing advice. It shows a possible situation and is not a photograph of a verified cultivar.
Put onion sets into the soil root-end down. The bulb belongs in the soil; only the dry tip stays above the surface.
View your supplies →The RHS profile describes Red Baron as having dark red skin and firm white flesh with red edges. De Bolster describes it as pungent and slightly flattened. That profile helps you choose. Label the bed with the variety from the start, so you later know which onions you tasted and under what name you stored them.
Onion sets are small bulbs starting the crop; seed starts with seedling development. Record which you used, otherwise comparing harvest dates is less useful. Check purchased stock is actually Red Baron and save packet guidance with the crop.
De Bolster gives direct March sowing until mid-April at latest. This guides seed onions, not all sets. The page's table and full text differ on spacing. Check current labels before laying out rows; table values become no universal bed rule.
Onions root shallowly, making reachable moisture important. Check below surfaces in drought before watering. Needs change when bulbs mature and foliage flops. Reassess plants then rather than automatically repeating earlier watering rhythms.
Weeds compete with young onions. Work regularly and carefully. Deep hoeing can damage roots or bulbs; hand-weeding beside onions is easier to control. Observe foliage and bulb development simultaneously, tracking more than row cleanliness.
Yellowing, flopping foliage helps recognise harvest stage. The RHS guide discourages deliberately bending leaves. Lift gently without bruising and separate damaged bulbs for prompt use. Calendars bring you to beds; plant condition determines what to do there.
Storage onions need thorough drying. Look for papery outer skins and dry roots; airflow aids curing. Use shelter in wet weather. De Bolster advises drying out of full sun. Record conditions so later storage problems are not attributed solely to variety.
Inspect stored onions regularly, using softening or sprouting bulbs first. Good-storage variety descriptions still require careful drying and inspection. Record quality progression and which batches were used first, continuing Red Baron's story beyond the bed season.
Tick what you already have. The extras depend on how you grow.
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SeedSteps editorial team · updated on 11 October 2026. The AI images illustrate species and practical growing situations; they do not prove an exact cultivar, observations from your own garden or yield.
Britse gewasadviezen worden gecombineerd met Nederlandse en Vlaamse informatie waar beschikbaar. Amerikaanse Extension-bronnen ondersteunen plantprincipes en herkenning; hun kalenderdata, lokale plaagdruk, bestrijdingsmiddelen en mestdoseringen worden niet rechtstreeks op Nederland of Vlaanderen toegepast. Vorst, bodemwarmte, standplaats en expliciete rasinformatie blijven de lokale controle. Commerciële bronnen onderbouwen uitsluitend benoemde ras- en plantkenmerken; zij zijn geen affiliate-aanbeveling.
Supporting evidence by chapter: A red skin with a recognisable interior: Royal Horticultural Society, De Bolster. Seeds and onion sets begin in different ways: Royal Horticultural Society. The Dutch sowing instructions have their own conditions: De Bolster. The roots are close to the surface: University of Minnesota Extension. Keep the row clear without damaging the bulb: University of Minnesota Extension. Let foliage indicate ripeness: Royal Horticultural Society. Drying is part of harvesting: Utah State University Extension, De Bolster. Stored crops need a round of checks too: Utah State University Extension, Royal Horticultural Society.
Height: 10-50 cm Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Light: Full sun Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Main colour: Dark red Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Secondary colour: White flesh with red edges Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Save: Stores well with suitable harvesting, drying and storage Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Flavour: Strong flavour Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Texture: Firm flesh Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society
Width: 10-50 cm Brits RHS-rasprofiel. Brongebonden beschrijving, geen vaste groei- of bewaargarantie voor Nederlandse of Vlaamse tuinen. Royal Horticultural Society