Best Time to Plant Onions in Texas: Frost-Free Window & Variety Guide

Planting onions in Texas at the right time means the difference between a bumper crop of sweet, tender bulbs and a sad, shriveled mess.

Texas gardeners know timing is everything—plant onions too early, and frost will ruin your crop; too late, and the heat will turn them bitter. Mastering the perfect planting window ensures sweet, robust onions all season long.

For Zone 8a-10b, the best months are October-November for fall planting and February-March for spring. These windows align with soil temps of 50-65°F, giving your 🧅 onions the ideal start before summer’s relentless heat arrives.

Below, I’ll break down the exact frost dates by region, the top varieties that thrive in Texas heat, and the one mistake that kills more onion crops here than anything else.

Texas onion planting calendar: frost dates, soil temps & best months

Texas spans USDA zones 8a-10b, creating dramatic differences in frost timing—North Texas (like Dallas) sees frost as early as November 15, while South Texas (Houston/San Antonio) may escape frost until January 15.

These variations mean your onion planting window shifts dramatically depending on location, and choosing the wrong time can mean bitter bulbs or frost damage.

Onions thrive in soil temperatures between 50-65°F. Below 50°F, growth slows dramatically, and above 75°F, bulbs bolt prematurely. In Texas, this means fall planting (October-November) is ideal for most regions, while spring planting (February-March) works in warmer zones like South Texas.

Raised beds warm up faster, giving you a 1-2 week earlier planting window compared to in-ground soil.

Texas gardeners must also account for short-day vs. long-day onion varieties. Short-day onions (like Texas Early White) mature faster in Texas' 10-14 hour daylight and are perfect for fall planting. Long-day varieties (such as Yellow Granex) need 14+ hours of daylight to form bulbs, making them better suited for spring planting in North Texas but risky in South Texas' longer days.

Here’s your Texas onion planting calendar, broken down by region and soil type:

For fall planting, aim to harvest before summer heat (target April-May harvests). In North Texas, this means planting short-day onions by November 1 to avoid winter dormancy.

In South Texas, you can push planting to late November thanks to milder winters, but monitor soil temps—below 50°F stalls growth.

Spring planting in Texas requires caution. North Texas gardeners should start Yellow Granex in February for a summer harvest, but avoid planting after March 15—the heat will cause bolting. Central and South Texas can extend spring planting to April 1, but use shade cloth to protect seedlings from intense sun.

Raised beds help here too, as they retain moisture longer during Texas' erratic spring rains.

Pro tip: Succession planting works in Texas! In North Texas, plant short-day onions every 2 weeks from October to December for staggered harvests.

In South Texas, you can even squeeze in a late summer planting (August) using raised beds—just cover seedlings with frost cloth if temps dip below 50°F.

One critical mistake Texas gardeners make? Planting onions in summer heat. Onion sets or seeds planted after April 15 in most regions will bolt immediately, producing seeds instead of bulbs.

If you’re desperate for summer onions, opt for green onions (scallions), which tolerate heat better and regrow after cutting.

Finally, test your soil pH

Top 5 onion varieties for Texas gardens & their planting strategies

Texas heat and variable frost dates demand heat-tolerant onion varieties that thrive in short-day conditions. The right variety ensures sweet, pungent-free bulbs and avoids bolting (premature flowering). Here are my top 5 picks for Texas gardens, each chosen for climate resilience and harvest consistency.

For fall planting (October–November), prioritize short-day varieties like Yellow Granex or Texas Early White. These bulbs mature before winter chill sets in, while spring planting (February–March) works best with long-day varieties like Candy or Texas Super Sweet—though they’re trickier in Texas’s 10–12 hour daylight.

🌱

Yellow Granex is my go-to for Texas gardens—its mild, sweet flavor and large bulb size (3–4 inches) make it ideal for fall harvests. Plant sets in October for bulbs ready by March. This short-day variety thrives in Texas’s 10–12 hour daylight and handles 80°F soil temps better than most.

Texas Early White, bred specifically for the state, matures in just 90 days—perfect for succession planting. Its white skins store well and resist purple blotch, a common Texas onion disease. For spring planting, start seeds indoors in February and transplant after last frost (typically mid-March in Central Texas).

Red Creole adds color and heat tolerance to your garden, with bulbs that redden in the sun. This short-to-intermediate day variety works well in South Texas (Zones 9–10) where longer daylight might trigger bolting in true short-day types. Space plants 4 inches apart and mulch with straw to retain moisture during 100°F+ spells.

For green onions or scallions, Evergreen Hardy White is a perennial option that regrows after cutting. Plant in fall or spring and harvest leaves as needed—ideal for container gardens or edible landscapes. Its cold hardiness (down to 15°F) makes it versatile for North Texas gardens.

To maximize yields, use succession planting: Sow onion sets every 2 weeks from October to December for a staggered harvest. In spring, repeat the process from February to April. Always water deeply (1 inch per week) and avoid overhead watering to prevent fungal diseases like downy mildew.

🌿