Growing Guide: The Incredible Onion

The Basics - Growing Onions

Onions’ hardiness, high yield, and easy storage make them a must-have in any avid Gardner’s crop.  Be aware, however, that onions planted from seeds can take up to 5 months to reach maturity.  So, if you’re starting from seeds, sow seeds indoors 8 to 10 weeks before the last average frost date—this is usually in February or early March.  If you’re starting with sets, plant them in late April or May.  With Green Valley fabric grow bags, you can do this indoors and simply carry your grow bag outside once weather permits.  With no transplants necessary, your seedlings are less likely to suffer from transplant shock.  Our pop-up plant cover will allow you to move seedlings outside in their grow bag weeks earlier if you need to free up space in your home.


What you'll need... 

  1. Green Valley Grow Bag 
  2. Seeds or sets
  3. Potting soil
  4. Seed Starter
  5. Trowel
Planting Care Harvest
  • Pour soil (and seed starter if necessary) into your grow bag; or, make sure your raised bed has about 10-12 inches of loose, loamy soil.
  • Plant seeds about ¼” away from each other, about ¼” deep in rows. Rows should be 4”-6” apart.  If you’re starting from sets, plant 3-4 small bulbs about 1” deep together—Brady Bunch style; groups should be 6” away from each other.
  • Keep soil moist. If the soil is dry when you’re planting, water immediately.
  • Place in direct sunlight or under plant lights.
  • Remember! Seeds can take up to two weeks to germinate, do not despair!
  • These little guys need water and warmth to germinate and grow!
  • Make sure they get lots of sun.
  • Add general nitrogen fertilizer every 2-3 weeks.
  • Move seedlings outdoors once they have 3 leaves.
  • Onions mature when their tops begin to fall over or yellow.
  • Once most leaves have fallen over, bend the rest over manually, stop watering them and wait for 2-3 days.
  • Pull your onions out and let them sun dry for about a week.
  • Harvest and store somewhere dry with sufficient air flow.

    Onion Life Cycle

    Onion Life-cycle


    Planting Onion Sets

    Planting Onion Sets

    Onion Seeds

    Onion Seeds




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