My 3 BEST Tips for Growing MASSIVE Onions Onions are one of the trickiest things to grow - it took me years to master it Here are a few more thoughts that I have on growing onions While it is possible to have success with sets I know I ll ruffle some feathers over this one you ll have the best shot at an abundant harvest when starting from seed Why are deep roots important Onions have shallow root systems and are prone to drying out so having deeper roots makes them so much more resilient Pick varieties that are known to store well so you can eat them through spring as long as you cure them properly My Favorite is Sedona F1 which is a l o n g -day onion so it s best for northern climates Pick a s h o r t -day onion if you