Tuesday, July 13, 2010

Growing Onions in Kihei

White Bermuda and Texas Early Grano

In Kihei, bulbing onions are a cool season crop - their germination and growth are negatively affected by the heat. With the exception of White Bermuda, I plant bulbing onion seeds from November through January. White Bermuda is the most heat tolerant onion I've grown and I've planted seeds as early as October.

Short day onion seeds are recommended for Hawaii. I didn't have success with bulbing onions until I grew seeds that were short day. Not all onion seeds note the day length on the package or in the catalog. If you're not trialing seeds, I recommend planting only the seeds that are noted as short day.

Texas Early Grano  is one of the varieties that's grown in Kula for sweet Maui onions. White Bermuda is the super-star of all of the onions I've grown. It's just as sweet and delicious as a sweet Maui onion. Unfortunately, untreated White Bermuda seed is not always available online.

Red Creole

Violet de Galmi, Texas Early Grano,
White Bermuda and Red Burgundy

Red onions need our coolest weather to grow to a normal size. Some red onions are less heat tolerant than others - my best results have been with Red Creole and Red Burgundy.

Red Creole seeds are available from 

Most of the bulbing onions I've grown could be stored at room temperature for several months.


 Pompei is a cipollini onion - they're small, flat and great for shish kebob 
but they weren't a storage onion.

White Bermuda
At 3 months

Onions take 4 to 5 months to grow from seed to maturity. They need full sun, daily water and twice monthly applications of fish emulsion or a monthly application of an organic all-purpose fertilizer. They grow well in containers with a soil depth of at least 7 inches.

Seedlings growing in half gallon size milk cartons.

I start onions in seedling pots rather than plant the seeds directly in the soil. I use a generous amount of seed and transplant the seedlings at 1 month. 

Prior to transplanting, I amend the soil with green sand and an organic all-purpose fertilizer. Container grown onions are seldom bothered by insects or moth larvae. The Kihei winter climate is hard on the green portion of the onions but as long as the bulbs are developing all is well.

Onion and leek seeds don't remain viable for very long, even when stored in the refrigerator. For best results, purchase fresh seeds prior to planting in the fall.

Sustainable Seed Company has a large selection of short day onion seeds.
According to their website, these onions are short day:
 Red Creole, Red Burgundy, Vidalia, Yellow Granex, Yellow Burmuda, White Bermuda, Crystal White Wax, Red Granex, Early Grano, Texas Grano, Torpedo Red

A CTAHR fact sheet on growing onions in Hawaii:


  1. Aloha Jane! How long does it take for red burgundy onions bulb in kihei

    ~ Caroline

  2. Hi Caroline! All of the bulbing onions I've grown have taken at least 4 months to grow to a harvestable size. In Kihei, if the onions aren't bulbing by 3 months then they probably won't bulb due to either the heat or the day length.