Spring onions are one of the most rewarding and straightforward crops to cultivate in a home setting. True spring onions are young plants of Allium cepa, the common bulbing onion, harvested before the bulb fully matures, resulting in a distinct, small, rounded base. Growing these vegetables requires minimal space and effort, making them an excellent choice for beginners, container gardening, or windowsill cultivation. Their rapid growth cycle and continuous harvest potential ensure a steady supply of fresh, mild onion flavor directly from your home garden.
Choosing Your Planting Method
Selecting the propagation method determines the timeline and effort required for growing spring onions. Planting from true seed is the most economical approach, allowing for a wide selection of varieties. Seeds should be sown thinly about a quarter-inch deep and require seven to fourteen days to germinate, with the first harvest ready in eight to twelve weeks. For a faster start, small onion bulbs, known as sets, can be planted directly into the soil a few inches apart, significantly reducing the time to maturity compared to seeds. The quickest method is regrowing from kitchen scraps, using the white base of a store-bought spring onion with the roots still attached. Place the root ends upright in a shallow glass of water. Once the roots have visibly regenerated, transfer the base to soil to prevent the plant from weakening and ensure a continuous supply.
Preparing the Growing Environment
When growing in containers, the vessel must be at least six to eight inches deep to accommodate the root structure and must feature effective drainage holes to prevent water accumulation. Spring onions thrive in a loose, well-draining, and nutrient-rich medium. A high-quality potting mix enriched with organic matter or compost is recommended over standard garden soil. The ideal location provides full sun, meaning the plants receive at least six hours of direct sunlight daily. If growing indoors, a bright south-facing window is the most suitable substitute. In areas with intense afternoon heat, providing partial shade prevents the tender green leaves from wilting or burning.
Ongoing Care and Maintenance
Consistent moisture management is essential once spring onions are established. The soil must be kept consistently moist but never waterlogged, which can lead to fungal diseases like downy mildew. Check the soil daily, especially in containers, and water thoroughly when the top inch of the mix feels dry.
Container-grown plants benefit from supplemental nutrients, as watering can wash away existing feed. Applying a weak liquid fertilizer, such as a balanced vegetable feed, every few weeks promotes vigorous growth. If starting from seeds, thinning the seedlings ensures the remaining plants have adequate space. When the young plants are about two inches tall, snip the weaker ones, leaving the strongest seedlings spaced two to four inches apart.
Harvesting Techniques and Regrowth
Spring onions are ready for harvest six to eight weeks after sowing seeds, or much sooner if started from scraps. There are two distinct methods for harvesting: full harvest or continuous yield. Harvesting the entire plant involves gently loosening the soil before pulling the whole onion, including the white base and roots, from the ground.
The cut-and-come-again technique ensures a steady supply of greens over an extended period. To perform this, use a sharp knife or scissors to cut the green stalks, leaving about one inch of the white stem and the root system intact above the soil line. This small portion allows the root base to regenerate foliage, which will be ready for cutting again within a few weeks.