Sowing Guide

How to Sow Spanish Giant Brown Onion Seeds

Growing Brown Onions from Seeds

Known for producing large, sweet onions, this superior variety of vegetable is a favourite among gardeners. Fully matured onions once harvested have excellent storage capabilities. Simply store in a cool dark place for long lasting onions. Also known as Spanish Utah, these fast growing onion seeds germinate in around 10-12 days, leading to a harvest approximately 120 days from germination. Each packet contains over 50 Giant Sweet Spanish Onion seeds, ideal for UK gardeners looking to grow exhibition-quality onions. With their large size, sweet flavour, and resistance to pests, Spanish Utah brown onions are an outstanding choice for gardeners aiming for a bountiful yield. Whether planted in greenhouses, allotments, poly tunnels, vegetable patches, gardens, or large containers, these aromatic sweet onions are sure to be a rewarding addition to any garden.

When to Sow Spanish Brown Onion Seeds in the UK

  • Sowing Temperature: For optimal germination, maintain soil temperatures around 13-25°C (55-77°F). This temperature range encourages quick and even sprouting of seeds.
  • Soil and Location: Choose a location with fertile, well-drained soil that receives full sunlight. Onions thrive in rich soil enhanced with organic compost, providing the nutrients necessary for robust growth.
  • Seed Sowing Advice: Sow seeds at a depth of 1/2 inch. Sow 2-3 seeds per inch and thin to 5 inches apart once the plants reach 6 inches in height.

Spring Sowing

  • Indoor Start: Begin indoors in late winter to early spring, around February to April, to get a jump on the growing season. This is especially useful for regions with shorter growing periods or cooler springs.
  • Outdoor Transplanting: Transplant seedlings outdoors when they are sturdy enough and the risk of frost has passed, typically from late April to May. Ensure soil temperatures have consistently reached 13-25°C (55-77°F) for best results.

Summer Sowing

  • Direct Sowing: For areas with a longer growing season, direct sowing outdoors can be done in early to mid-summer, around June to July. This timing is ideal for harvesting in late autumn or early winter.
  • Considerations: Ensure the soil is warm and there’s enough time for the onions to mature before the colder months. Summer sowing may require additional watering to keep the soil moist due to higher temperatures.

Autumn Sowing

  • Overwintering: In milder UK regions, sowing in autumn for overwintering can yield an early harvest the following year. Sow directly in the ground in September or October.
  • Protection: Provide protection with fleece or a cloche as temperatures drop to shield young plants from severe frost and ensure their survival over winter.

Caring for Onion Seedlings

  • Transplanting: When transplanting seedlings outdoors, clip the plants to three inches and plant them 2 inches deep. Space the plants 5 inches apart in rows that are 18 inches apart to allow for ample growth.
  • Maintenance: Keep the soil moist but not waterlogged. Onions benefit from regular watering, especially during dry periods, to develop their full size and flavour.
  • Companion Planting: Onions are excellent companion plants for lettuce, cabbage, and carrots, helping to deter pests and promote a healthy, diverse vegetable garden.
  • Harvesting: Harvest the onions when the tops are brown and dry, typically around 120 days from germination. Gently pull the bulbs from the soil. Spanish Giant Brown onions are known for their large size, crisp thin brown skin, and sweet juicy white flesh, making them perfect for both raw and cooked dishes.
  • Storage: These onions boast excellent storage capabilities. Once harvested, cure the onions in a dry, well-ventilated area before storing them in a cool, dark place to prolong their shelf life to over 3 months.
  • Watering: Onions require consistent moisture, especially during dry spells. Water regularly to keep the soil evenly moist but not waterlogged.
  • Weeding: Keep the area around onions free from weeds, which compete for nutrients and water. Gentle hand weeding is preferred to avoid disturbing the onion roots.
  • Mulching: Applying a layer of organic mulch helps retain soil moisture, suppress weeds, and regulate soil temperature.

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