Walla Walla Onion Seeds - Non-GMO & Heirloom. 110 days. Intermediate day type. Recommended by USU. Some say this is the world's best tasting onion. A delicious, mild, sweet onion, measuring about 4 inches across. In mild-winter areas plant in August for harvest early next summer. Does not keep well. Very limited quantities available. Approx. 8,140 seeds/oz.