Onions and Sunflowers

This year, we decided to try something different— growing onions and sunflowers together. As we are in USDA zone 8b, we put onions in the garden in February and then sunflowers after danger of frost.

Picture of Onions and Sunflower seedlings

Onions and Sunflowers Apr20-2014

The onions are growing well and will be out of the garden by mid-May and the Sunflowers will probably start blooming shortly after that time.

There are two ways to set this up; (1) try and see what happens or (2) check plant compatibility for preferred moisture, soil pH, nutritional needs, and then try to match conditions as best as possible (In our garden, we will err on the side of the onions if there are any major difference because we place greater value on harvesting onions, over sunflowers. (We can always put a few sunflowers elsewhere in the garden since we plant them as ornamentals.)

A few Pros and Cons (onions and sunflowers):


  • sunflowers have a head start for summer and don’t have to be transplanted— that’s especially important in Texas where little grows once the dog days of summer arrive.
  • Sunflowers are pretty tolerant and not very picky, they should grow just fine with onions.
  • Sunflowers and onions are in different families so there shouldn’t be any common pests amplified due to the extended period of time for plant growth.


  •  The sunflowers need nutrients and can potentially reduce onion size—onions are heavy feeders and may lose some nutrients to the sunflowers. (We are going to observe for differences at onion harvest.)
  • Harvesting onions will possible damage sunflower roots. (We’ll be checking as we harvest.)

Happy gardening!


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