Spring onions, also known as green onions or bunching onions, can be grown almost all year round bar the coldest winter months. When you know how to grow spring onions successfully, you can receive a continuous harvest throughout the year.
They are versatile and can be grown easily from seeds in water, pots, or sown directly in the ground. As they have a quick maturity rate, it is best to sow fresh seeds regularly throughout the growing season to replace harvested onions and ensure they return the following year due to being perennial plants.
If you want to grow spring onions at home, keep on reading for top tips on when and how to plant them for a good harvest.
How To Grow Spring Onions
Spring onions do not take as long to grow as other onion varieties. They are much smaller and are harvested prematurely before they have developed that classic, rugged outer skin found on brown and red onions.
They can be sown anytime between March and October when there is no risk of frost. Once sown, they can take around 8 weeks to mature ready for harvesting. If using sets or slips, this process can be much quicker.
Prepare the Ground
Though they do not take up much space, the soil in which you plant your spring onions does require turning and ensuring it has the right conditions for your onions to grow.
Spring onions grow best in a pH between 6.0 and 7.0 with nutrient-rich soil. You can improve your ground soil by adding and turning compost, along with removing hard lumps or stones from the area.
Turning your soil also helps limit the risk of the ground becoming waterlogged and your onions being too damp.
If you are choosing to grow your onions in pots, the same conditions apply in terms of soil quality. You can use high-quality compost in each pot and position your pot where necessary in your garden.
Spring onions require an area of your backyard which has access to direct sunlight. To thrive, spring onions need a minimum of 6 hours of sunlight each day.
How To Grow Spring Onions in Pots
Before planting your spring onions, ensure to have selected a pot with good drainage. Fill each container up to the brim with compost.
If planting from seed, scatter seeds across the top of the pot and cover with a further inch of soil. Gently spray the surface with water. The pot will need to be placed in a sunny area and watered regularly as the seeds grow.
Once seedlings show, you can separate and re-pot to avoid overcrowding. The seedlings will then take a further 6-8 weeks until they need harvesting. Remember to regularly water each pot to avoid the soil becoming too dry.
Sets or slips can also be grown in pots but require planting deeper into the soil. When planting slips, make sure to cover the root of the plant. If planting sets, ensure the pointed end of the bulb is facing upwards and covered in soil.
How To Grow Spring Onions From Seeds
Once the ground temperatures have increased to at least 20 degrees and the frost has finished, spring onion seeds can be planted directly outdoors.
Select an area with good quality soil, the right pH level, and direct sunlight. Each spring onion needs to be planted 20mm deep and with a 10cm distance between individual seeds.
This provides them with enough space to grow and limits the risk of competition between plants. If needed, once seedlings appear they can be thinned and replanted to create additional space.
After 8 weeks from sowing, your spring onions are ready to be harvested.
For a regular supply of spring onions throughout their growing season, it is best to continue planting batches of fresh seeds every few weeks. This will provide a consistent crop of spring onions that can be harvested during the Spring and Summer months.
If you are wanting to get a head start on the following year, consider planting a fresh batch of seeds in September. Once the seedlings have begun to grow, cover the ground with mulch such as straw, to help discourage weeds from growing and protecting the soil and your seedlings.
Over the winter months, your spring onions will become dormant until the temperatures increase in early Spring.
How To Grow Spring Onions in Water
Unlike many crops, spring onions can regenerate and thrive in just a glass of water. This method can work well for someone who doesn’t have direct sunlight in their garden or has limited space and resources.
To use this method, you can either purchase spring onions from the supermarket or, use a set of spring onions grown from your garden. The spring onions need to have their roots still attached for this method to work.
Cut up to 5cm off the top of your spring onions to use at home. Place the rest of your spring onions, root ends down, in a clear glass jar or cup. Fill the glass with water up to where the white bulb end finishes.
The jar needs to be placed in a sunny position and the water replaced every 2-3 days. Then simply wait and watch as your spring onions do all the work and continue to grow back fresh leaves.
Select which of these methods of growing spring onions works best for you and your available space at home. Once you have started to grow spring onions, continue to sow fresh seeds every few weeks, and, place fully mature spring onions in water to provide you with a regular supply throughout the year.
Take a look at these posts below for more top tips and guides to help you grow even more vegetables at home: