Planting Guides

When to Plant Onions in Austin: Complete Guide + Best Varieties for Zone 8b

Austin, Texas

USDA Zone 8b

Last Frost: Mar 1

Last updated: October 30, 2025

Learn when to plant onions in Austin with specific dates for Zone 8b. Compare 6 varieties, get a complete timeline, and discover which onions grow best in Texas.

CCarlos Mendez

October 30, 2025

When to plant onions in Austin - healthy onion plants in Zone 8b garden showing proper fall planting results — — Image © PlantReference.org 2026

Quick Answer

Plant short-day onion transplants October 15-December 15 in Austin for spring harvest. Fall planting allows cool-weather growth before March bulbing triggers.

TL;DR

Plant short-day onions in Austin from October 15-December 15 for spring harvest. Allium cepa 'Texas Super Sweet' and Allium cepa 'Red Creole' thrive in Zone 8b's mild winters. Fall planting allows 4-5 months of cool-weather growth before bulbing triggers in March-April. Garlic cloves plant November 1-30 for July harvest.

Frequently Asked Questions

When is the best time to plant onions in Austin?

Plant onion transplants from October 15 to December 15, with the optimal window being November 1-15. This timing allows 4-5 months of cool-weather growth before bulbing begins in March. Austin's Zone 8b climate requires short-day onion varieties planted in fall for spring harvest—spring planting typically fails due to heat stress and wrong day-length triggers.

What onion varieties grow best in Austin's climate?

Short-day varieties are essential for Austin success. Allium cepa 'Texas Super Sweet' was developed specifically for Texas conditions and produces large, mild bulbs. Allium cepa 'Red Creole' offers better storage life, while Allium cepa '1015Y Super Sweet' creates jumbo-sized onions. Never plant long-day varieties like 'Walla Walla' in Austin—they won't form bulbs at our 30°N latitude.

Can I plant onions from seed in Austin?

Transplants are strongly recommended over seeds for Austin gardeners. The fall planting timing makes direct seeding challenging, and transplants establish more reliably in clay soil. If using seeds, start them indoors in August and transplant in October-November. Most successful Austin gardeners purchase transplants from local nurseries that carry appropriate short-day varieties.

Why did my onions bolt instead of forming bulbs?

Bolting (premature flowering) in Austin usually results from using long-day onion varieties not suited for our latitude, or planting too early when soil temperatures exceed 80°F. Temperature fluctuations during winter cold snaps can also trigger bolting. Stick to short-day varieties and wait for November planting to avoid this problem.

How do I know when onions are ready to harvest in Austin?

Begin harvest when 50% of tops fall over naturally, typically mid-April to mid-May in Austin. Don't wait for all tops to die back—Austin heat arrives quickly and can damage bulbs left in ground too long. Harvest during dry weather and cure in a ventilated area for 2-4 weeks before storage.

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Tagged with

#onions #Austin gardening #Zone 8b planting #short-day onions #Texas gardening #fall planting #garlic growing #clay soil gardening #onion varieties #harvest timing

Written By

Carlos Mendez

Carlos grew up helping his abuelos tend their backyard garden in San Antonio, Texas, but didn't get serious about growing his own food until he bought his first house in Austin. He works as an HVAC technician during the day and gardens in the early mornings and evenings. Carlos specializes in heat-tolerant vegetables and container growing—essential skills for Texas summers and his south-facing driveway that gets intense sun. He's learned through plenty of failures (multiple dead fig trees, countless bolted lettuce crops) and now helps neighbors troubleshoot their own gardens. His YouTube channel documenting his container tomato experiments has a small but dedicated following. Carlos is passionate about growing food on a budget, often sourcing free containers and building his own compost.