If you are wondering when to plant onions in Texas, the answer depends on your region and the type of onion you choose. Texas offers a longer growing window, so plant your onion transplants in late winter for a spring harvest. This guide covers everything you need to know for a successful crop.
When To Plant Onions In Texas
Onions are a cool-season crop that thrives in Texas’s mild winters and warm springs. The exact timing varies across the state, but the general rule is to plant in late winter for a late spring or early summer harvest. Onions need cool weather to develop tops and warm weather to form bulbs.
Understanding Texas Growing Zones
Texas spans USDA hardiness zones 6 through 9. This means planting dates shift by several weeks from north to south. In North Texas (zones 6-7), plant in February or early March. In Central Texas (zone 8), aim for January to February. South Texas (zone 9) can plant as early as December or January.
Key Factors That Affect Planting Time
- Day length: Onions are photoperiod-sensitive. Short-day onions bulb when days are 10-12 hours long, perfect for southern Texas. Intermediate-day onions work for central areas. Long-day onions are not ideal for most of Texas.
- Soil temperature: Onions germinate best when soil is between 50°F and 75°F. Too cold and seeds rot. Too hot and bulbs may not form.
- Frost dates: Onions can tolerate light frost, but hard freezes below 28°F can damage young plants. Plant after the last hard frost in your area.
Best Time For Onion Transplants Vs Seeds
Most Texas gardeners use onion transplants or sets instead of seeds. Transplants give you a head start and are easier to manage. Plant them 4-6 weeks before the last expected frost. For seeds, start indoors 8-10 weeks before transplanting, or direct sow in fall for a spring harvest in mild areas.
When To Plant Onion Sets In Texas
Onion sets are small bulbs grown from seed the previous year. They are less common in Texas because they often bolt (flower early) or produce small bulbs. If you use sets, plant them in late winter, same as transplants. Choose short-day varieties for best results.
Regional Planting Calendar For Texas
Here is a simple breakdown by region. Adjust based on your local weather patterns.
- North Texas (Dallas, Fort Worth, Amarillo): Plant transplants from mid-February to mid-March. Harvest in June to July.
- Central Texas (Austin, San Antonio, Houston): Plant from January to February. Harvest in May to June.
- South Texas (Corpus Christi, Brownsville, Laredo): Plant from December to January. Harvest in April to May.
- West Texas (El Paso, Midland): Plant in March. Harvest in July to August.
Fall Planting For Onions In Texas
Some Texas gardeners plant onions in fall for a spring harvest. This works best in mild winter areas like South Texas. Plant transplants in October or November. They grow slowly over winter and bulb in spring. This method avoids the heat stress of summer.
How To Plant Onions Step By Step
Follow these steps for a strong start.
- Choose short-day or intermediate-day varieties. Examples: Texas Grano, Texas Sweet, Red Burgundy, Candy.
- Prepare the soil. Onions need loose, well-draining soil with a pH of 6.0 to 7.0. Add compost or aged manure.
- Plant transplants 1 inch deep, spacing them 4-6 inches apart. Rows should be 12-18 inches apart.
- Water thoroughly after planting. Keep soil moist but not waterlogged.
- Mulch around plants to retain moisture and suppress weeds.
Soil Preparation Tips
Onions are heavy feeders. Before planting, mix in a balanced fertilizer like 10-10-10. Avoid high-nitrogen fertilizers after bulbs start forming, as they promote leaf growth over bulb development. Test your soil pH if possible.
Common Mistakes When Planting Onions In Texas
Many beginners get the timing wrong. Here are frequent errors to avoid.
- Planting too late: Onions need cool weather for top growth. If you wait until April, bulbs may not form before summer heat.
- Planting too deep: Onions should be set just deep enough to cover the roots. Deep planting can cause rot or misshapen bulbs.
- Using long-day varieties: These are bred for northern states. In Texas, they often produce small bulbs or none at all.
- Overwatering: Onions need consistent moisture, but soggy soil leads to fungal diseases. Water deeply once a week.
When To Harvest Onions In Texas
Harvest time depends on planting date and variety. Look for signs like yellowing tops and bulbs pushing above soil. Stop watering 2-3 weeks before harvest to allow bulbs to cure. Pull them up on a dry day.
Curing And Storing Onions
After harvest, cure onions in a warm, dry, well-ventilated area for 2-3 weeks. Trim tops to 1 inch and store in a cool, dark place. Properly cured onions can last for months.
Frequently Asked Questions
Can I plant onions in the spring in Texas?
Yes, but only if you use transplants and plant early. Spring-planted onions may not bulb fully if heat arrives too fast. Fall planting is often better for larger bulbs.
What is the best onion variety for Texas?
Short-day varieties like Texas Grano, Texas Sweet, and Red Burgundy perform best. Intermediate-day varieties like Candy also work in central regions.
How deep should I plant onion transplants?
Plant them about 1 inch deep, with the roots fully covered and the neck just above soil level. Do not bury the entire stem.
Do onions need full sun in Texas?
Yes, onions need at least 6-8 hours of direct sunlight daily. Partial shade can reduce bulb size.
Can I grow onions from kitchen scraps?
You can regrow green tops from onion bottoms, but they will not form full bulbs. For bulb onions, use transplants or seeds.
Final Tips For Success
Onions are one of the easiest crops for Texas gardeners if you get the timing right. Start with short-day varieties, plant in late winter or early fall, and keep soil consistently moist. Watch for pests like onion thrips and diseases like downy mildew. Rotate crops each year to prevent soil-borne issues.
Remember that local weather can vary. Check your specific frost dates and soil temperatures before planting. A soil thermometer is a cheap tool that saves you from guessing. With a little planning, you will enjoy a bountiful harvest of sweet, homegrown onions.
If you are still unsure when to plant onions in texas, start by looking up your county’s average last frost date. Then count backward 4-6 weeks for transplants. That simple calculation will set you up for success. Happy gardening!