When to Plant Onions in Texas

October through December is the main planting window for bulb-onion seed in Texas; set out transplants in January or February. These statewide windows give onions time to grow leaves before lengthening spring days trigger bulb formation. The best plan combines the right planting material, a locally adapted variety, and soil conditions that let young plants establish well.

Why Texas Onions Need an Early Start

For bulb onions, planting time and day-length type have to work together.

Onions first grow roots and leaves, then shift toward bulb formation when daylight reaches the variety’s trigger. A well-established plant has more leaf growth to support a substantial bulb. An onion planted late may survive perfectly well but produce a disappointing harvest because it had too little growing time before bulbing began.

That is why Texas onions do not follow the same calendar as tomatoes and peppers.

Planting material also changes the calendar. A seed needs time to become a seedling; a transplant has already completed that stage.

How to Plant Onions in Texas for Bulbs

Choose your starting material before buying seed or preparing the bed.

Starting Material	Statewide Planting Window	Main Trade-Off
Bulb-onion seed	October through December	Lowest cost, but requires an earlier start and more seedling care
Transplants, also sold as onion starts	January or February	Already-growing plants make establishment simpler

Step 1: Choose a Texas-Adapted Onion Variety

1. Short-day onions commonly begin forming bulbs at 11 to 12 hours of daylight and are the usual starting point for much of Texas. The response varies by cultivar, so confirm the named variety’s day-length classification on its seed packet or transplant listing.
2. Choose a named variety rather than color alone. Texas-adapted short-day examples include TX 1015Y, Early Grano 502, and Granex for yellow onions; TX Early White for white onions; and Red Burgundy for red onions. A packet marked only “yellow onion” leaves the variety unspecified.
3. Identify what you are buying. Transplants are leafy seedlings, often sold in bundles. Sets are small, dry bulbs. Both can be planted, but an unidentified bag of sets is a less dependable choice for bulb production than a named, locally adapted variety.

Intermediate-day varieties may also be an option. Avoid assuming that every part of the state needs the same cultivar, or that a long-day onion will bulb properly simply because its leaves grow well.

Step 2: Prepare the Soil and Preplant Fertilizer

1. Choose a sunny, well-drained bed. Before seeding or transplanting, work the soil 8 to 10 inches deep. Break up large clods and finish with an even surface so shallowly planted seeds and starts make good contact with the soil.
2. Use soil-test guidance when available. Where there is no soil-test-specific fertilizer plan, the general preplant recommendation is 2 to 3 pounds of 10-10-10 per 100 square feet of garden area, according to Texas A&M AgriLife Extension. Distribute it across the planting area and incorporate it into the prepared soil rather than concentrating it beneath individual plants. For a 50-square-foot bed, that works out to 1 to 1½ pounds total. This is a garden-bed recommendation, not a fertilizer dose for a single pot.
3. Avoid stacking fertilizer programs. If a soil test provides a different blend or application rate, use that tailored recommendation instead of adding it on top of the general treatment.

Step 3: Sow Seeds or Plant Starts

Choose the planting action that matches your material, then water it in.

1. For bulb-onion seed: Sow during October through December, placing seeds ¼ inch deep and 1 inch apart, following Texas A&M AgriLife Extension’s onion planting guidance. Cover lightly and gently firm the surface. This shallow sowing depth is different from the depth used for starts.
2. For transplants or sets: Plant transplants in January or February; place transplants or sets ¾ inch deep and 3 inches apart. Keep the green growth above the soil.
3. Finish either planting by watering gently. Settle the soil around roots or seeds without washing them out of position. Keep the seedbed moist during emergence, but avoid leaving it waterlogged.

Step 4: Thin Seedlings and Support Leaf Growth

1. Thin seed-grown onions after emergence. When seedlings are about 6 inches high, thin to one plant every 2 to 3 inches. The removed plants can be eaten as green onions.
2. Water slowly and deeply. Once a week is usually enough in spring, although dry, windy weather may require more frequent watering, according to Texas A&M AgriLife Extension. Account for rainfall rather than automatically watering an already-wet bed.
3. Feed at the leaf-development stage. For the general 10-10-10 garden-fertilizer program, side-dress when plants have 5 to 6 leaves, using about ½ cup of fertilizer for each 10 feet of onion row. That amount applies to the general 10-10-10 program. Scatter it alongside the plants and water it in. Do not treat that volume as an interchangeable dose for a more concentrated fertilizer.
4. Keep weeds from taking over. Pull or cut weeds when they are 3 to 4 inches tall. Onions compete poorly with established weeds and grasses, so do not wait until the planting disappears beneath them.

The aim during this stage is steady growth.

Step 5: Harvest and Dry the Bulbs

1. Plan for a May through July bulb harvest after fall seeding or winter transplanting. Variety, location, and growing conditions determine where your crop falls within it.
2. Let the plants show maturity. For dry-bulb onions, wait for the main stem or neck to weaken and the tops to begin falling. The calendar helps you plan, but it is not a command to pull every plant on the same day.
3. Lift and begin drying the onions. In dry weather, leave harvested bulbs lying in the garden for 1 to 2 days to dry. If rain threatens, move them to a dry, sheltered place with good airflow rather than leaving them on wet soil.
4. Finish curing before storage. Continue drying in a shaded, well-ventilated place until the necks and outer skins are dry. Keep sound bulbs in a cool, dry, ventilated location, and use damaged bulbs promptly rather than mixing them into the storage crop.

Do not seal freshly pulled, damp onions in bags. Sweet onion varieties also generally have a shorter storage life than pungent storage types, so plan to use those bulbs first.

How Location Changes the Texas Planting Plan

Texas is too large for one exact planting day to suit every garden. Local conditions refine the statewide calendar; they do not replace it.

North Texas and the Panhandle

Cold spells and soil conditions deserve particular attention in northern and higher-elevation gardens. Choose a day when the bed is workable, and avoid setting out young plants immediately ahead of severe weather.

Do not assume that a variety recommendation automatically fits every location.

Central Texas

The main distinction is whether you are starting the crop from seed or buying plants that have already grown through the seedling stage.

If you reach winter without established seedlings, transplants are the straightforward choice for a bulb crop.

East Texas, Southeast Texas, and Galveston

Drainage and wet planting conditions can be as important as the calendar.

Wait for workable soil rather than forcing planting into a waterlogged bed. In Galveston and other coastal gardens, focus on the winter-to-spring growing season rather than assuming mild weather makes every month equally suitable for bulbs.

When You Want Green Onions Instead of Bulbs

Growing onions for green tops is a different goal from producing mature storage bulbs. You are harvesting a young plant rather than waiting for it to complete bulb development.

Bulb-onion plants can be harvested as green onions from the time they are pencil size until they begin forming bulbs. Pull the plants you want to use and leave the rest to continue growing.

If greens are your main goal, bunching or scallion varieties are another option. Their value is in the tender leaves and stems, so successful harvest does not depend on producing a large, rounded bulb.

Keep plants intended for green harvest separate from those you want to size up. Repeatedly cutting the foliage from a developing bulb onion removes the leaves that support bulb growth.

Signs Your Onion Crop Is on Track

Extra fertilizer cannot correct a poorly matched growing plan.

Before treating small onions as a nutrient problem, check the whole growing plan. Late establishment, crowding, unsuitable varieties, and inconsistent moisture can all limit bulb size.

A healthy crop should show:

• New, upright leaf growth after establishment.
• Evenly moist soil.
• Little competition from weeds or grasses.
• Bulb swelling as the variety reaches its seasonal day-length trigger.

Healthy green tops with little bulb development can signal a variety mismatch. Small but normally shaped bulbs may reflect limited growth.

A flower stalk is another useful warning. Prioritize bolted onions for fresh use rather than long storage.

At planting, write the variety name and date on a durable marker or garden record. Those two details make it much easier to improve next season’s timing instead of guessing why a crop stayed small.

Frequently Asked Questions

Can I Grow Onions in Pots in East Texas?

Yes, provided the container drains freely and receives full sun. Allow 3 inches between bulb-onion transplants rather than packing the pot tightly. Container growing does not change an onion’s day-length requirements, and the growing mix may dry faster than a garden bed, so check its moisture instead of applying a fixed bed-watering schedule.

Can You Grow Onions From Scraps?

Yes, rooted green-onion bases can regrow edible tops, but they are not a dependable substitute for seed or transplants when you want full-size bulbs. Plant the rooted base with the roots covered and the growing tip above moist potting mix. Keep it in good light and clip new leaves while leaving the growing base intact.

Is There a PDF With Fertilizer Recommendations for Onions?

Yes, there is a PDF with fertilizer recommendations for onions. It also covers planting and harvest guidance. It includes preplant fertilizer rates, follow-up feeding, planting instructions, and harvest guidance. Its general garden-bed recommendations are useful starting points; a soil test can tailor nutrient applications to what your own soil needs.

When should you plant bulb onions near Galveston and elsewhere in Southeast Texas?

Near Galveston and elsewhere in Southeast Texas, sow bulb-onion seed from October through December or set out transplants in January or February. Give the crop direct sun and soil that drains readily.

How should you plant bulb onions in Central or North Texas?

For bulb onions in Central or North Texas, place seed a quarter inch below the surface from October through December, leaving 1 inch between seeds. If you plant transplants or sets instead, position them ¾ inch deep and 3 inches apart.

How should you fertilize onions?

Before planting, incorporate 2 to 3 pounds of 10-10-10 fertilizer into each 100 square feet of bed. When plants have 5 to 6 leaves, apply about ½ cup of fertilizer per 10 feet of row and water afterward.

When should you plant TX 1015Y or other bulb onions in Texas?

Plant TX 1015Y and other bulb onions by sowing seed from October through December or setting out transplants in January or February. TX 1015Y is included on Texas A&M’s yellow-onion variety list.