Yellow & Red Onion Seeds – Utah Yellow & Red Creole

Yellow & Red Onion Seeds for Planting – Utah Yellow & Red Creole – Non-GMO Heirloom Seeds (Allium cepa) include two classic bulb onion varieties with distinctly different colors, flavors, and day-length requirements. Utah Yellow Onion (Yellow Sweet Spanish Utah) produces large, globe-shaped bulbs with golden-yellow to copper-colored skins and crisp white flesh. It has a mild, sweet flavor that is excellent for slicing, cooking, grilling, and caramelizing. Red Creole Onion produces smaller to medium-sized bulbs with reddish-purple skins and firm, flavorful flesh with a stronger, spicy-sweet onion taste that becomes milder when cooked.

The main difference between these two varieties is their color, flavor, bulb size, and preferred growing region. Utah Yellow is a long-day onion that can produce large 3½–6-inch bulbs and performs best in northern growing regions. Red Creole is a short-day onion developed for southern climates, typically producing 3–4-inch bulbs with excellent storage potential.

Planting Season

Best planted in: Early Spring, with Fall Planting Possible in Mild Climates (Cool-Season Crop)

Start seeds indoors approximately 8–12 weeks before the last expected spring frost, or direct sow outdoors as soon as the soil can be worked.

Utah Yellow can be sown approximately 4–6 weeks before the last frost and performs best as a long-day onion. Red Creole is better suited to short-day regions and can be planted in fall or winter in warm southern climates for a spring harvest.

Onion seeds germinate well when soil temperatures are approximately 60–85°F (16–29°C), although established plants tolerate cool weather and light frost.

How to Grow Yellow & Red Onion Seeds

Start seeds indoors in trays or sow directly into fertile, loose, well-drained soil.

Sow seeds approximately ¼–½ inch deep.

Keep the soil consistently moist during germination but not waterlogged.

Seeds typically germinate within approximately 7–15 days under favorable conditions.

Choose a location receiving at least 6–8 hours of direct sunlight daily.

Thin or transplant seedlings approximately 4–6 inches apart, with rows spaced about 12–16 inches apart. Utah Yellow benefits from slightly wider spacing when growing for extra-large bulbs.

Mix compost or aged organic matter into the soil before planting. Avoid compacted or poorly drained soil because onions have shallow root systems.

Container growing is possible in wide containers at least 8–10 inches deep with good drainage.

How to Care for Yellow & Red Onion Plants

Water consistently throughout active growth, keeping the soil evenly moist while the bulbs are developing.

Apply mulch around plants to conserve moisture, suppress weeds, and protect the shallow roots.

Feed with a balanced vegetable fertilizer during early growth. Avoid excessive nitrogen once bulbs begin enlarging.

Keep the planting area weed-free because onions compete poorly with weeds.

Monitor for common onion pests such as thrips and onion maggots. Good drainage, crop rotation, and adequate airflow help reduce fungal and bulb diseases.

Utah Yellow generally matures in approximately 110–130 days, producing large golden bulbs with mild, sweet flavor.

Red Creole generally matures around 110 days after transplanting, although maturity varies with climate and planting season. It produces reddish-purple bulbs with a stronger flavor and can store for several months when properly cured.

Harvest when the tops begin to yellow, fall over, and dry naturally. Lift the bulbs carefully and cure them in a dry, well-ventilated location until the outer skins become papery.

After curing, trim the roots and tops and store bulbs in a cool, dry, dark place with good airflow. Red Creole is particularly well suited to storage and may keep for up to approximately six months under favorable conditions.

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