Onion crop sheet


Onions are believed to be the oldest cultivated vegetable in the world. They are bulbs which are underground storage organs. Onions can be grown from seeds or sets. 

  • Estimated time: 30 minutes
  • Location: Outdoors & Indoors
  • School term: Early Autumn, Late Autumn, Late Spring
  • Level of experience: No experience needed
  • Subject(s): Science

Learning objectives

  • Learn how to sow seeds or bulbs
  • Learn what seeds and plants need to grow
  • Learn to plant at a specified distance
  • Learn to harvest vegetables


Organic matter or fertiliser should be incorporated at least one month beforehand.
The soil, raised bed or planter should have already been cultivated, weed free with a fine, crumbly texture ready for planting.

Equipment needed

  • Rake or hand cultivator
  • Measuring stick
  • Onion sets purchased from a garden shop (correct variety for time of year)
  • Label and pencil

Step by step

Buy autumn onion sets to plant from September to November or spring sets from February to early April. 

  1. Make a shallow drill about 2cm deep in the soil, using the measuring stick .
  2. Space the onion sets 10-15cm apart. Make sure they are the right way up with the roots at the bottom.
  3. Gently push the bulbs into the soil so that just the tip is showing above the soil surface. 
  4. Make the next row 30-40cm away and remember to label each row.
  5. Keep the area weed free and watch out for birds pulling the onion sets up.
  6. Wait for the leaves to die down in the summer, lift the onion bulbs and leave them to dry on the surface of the soil. When they are fully dry the onions are ready for storing.

Onion seeds can be sown late summer or spring.

Hints & tips

  • Growing onions from sets rather than seed means that they are less prone to disease and provide reasonable crops in poorer soils

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