UC IPM Home > Homes, Gardens, Landscapes, and Turf > Vegetables > Cultural Tips
How to Manage Pests
Pests in Gardens and Landscapes
Time to plant
Onions: Temperature plays an important role in
the development of onion bulbs. However, in order to
initiate bulb formation, day length is more critical.
Each onion variety has a critical day length for inducement
of bulbing regardless of temperature or plant size. Short-day
onions require day lengths of 12 to 14 hours. Long-day
varieties require 14 to 16 hours of day length. Growing
onions at less than critical day length results in formation
of new leaves but no bulbing. When short-day onions are
grown under long-day conditions, bulbing develops while
the plants are very small and results in small bulbs
(great for cocktail onions).
Garlic: Garlic is generally best planted in the fall for largest size bulbs at harvest. Later planting
is acceptable but bulb size may be smaller. Bulb formation begins in response to lengthening days.
In cold-winter areas, mulches around the plants will protect them from severe cold.
Garlic and onions are suitable for a small garden if
compact varieties are grown. In a suitable climate, green
onions may be planted more than once a year for a continuous
harvest. |
Planting
Dates for Onions and Garlic* |
CALIFORNIA |
Transplant or direct
seed |
North and North Coast
Monterey County north |
Oct.–Dec.
(garlic)
April–July
(green onions)
Jan. - Mar.
(bulb onions) |
South Coast
San Luis Obispo County south |
Oct.–Dec. (garlic)
All year
(green onions)
Feb.–March
(bulb onions) |
Interior Valleys
Sacramento, San Joaquin valleys |
Oct.–Dec.
(garlic)
Aug.–Dec.
(green onions)
Nov.–March
(bulb onions) |
Desert Valleys
Imperial and Coachella valleys |
Sept.–Nov.
(garlic)
Sept.–Jan.
(green onions)
Oct.–Nov.
(bulb onions) |
*Areas are large, so planting dates are only approximate,
as the climate may vary even in small sections of the
state. Contact experienced gardeners in your community
and experiment on your own to find more precise dates. |
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