Question
The red onions I've previously grown in Toronto, Ontario have had vibrant greens, but, when harvested, the bulbs were small.  Is there a trick to force the growth into the bulbs?

Answer
Jacob, small bulbs with lush foliage is caused by excess nitrogen in the soil along with a deficiency in potassium.  The secret is to plant bulb producing plants in soil high in organic matter.  These amendments include compost, peat moss, shredded leaves, dried grass clippings, and aged manure.

Once the foliage reaches 8", add a granular fertilizer high in potassium.  Potassium, also referred to as potash, is the third number in the ratio on the front of the bag.  This ratio is referred to as NPP, which stands for nitrogen, phosphorus, and potassium.  Nitrogen produces lush foliage; phosphorus strong stems and flowers; and potassium for healthy roots and larger bulbs.

I hope this answered your question.  Please write again if I can ever be of assistance.

Regards,

Mike