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Nothing kills the start of a growing season faster than a bag of dried-out onion sets that crumble to dust the moment you open it. The difference between a pantry full of storage onions and a disappointing handful of green tops often comes down to the viability of the bulbs you plant, not your soil preparation or watering schedule.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. I study market pricing trends, compare germination data across suppliers, and analyze aggregated owner feedback to separate the consistently harvested crops from the single-season disappointments.
Choosing the right batch of long day onion seeds means matching the day-length trigger to your region’s summer solstice hours, and the options below cover everything from heirloom bunching varieties to premium mixed color sets that overwinter well in colder zones.
How To Choose The Best Long Day Onion Seeds
Long-day onions begin forming bulbs when daylight exceeds 14 to 16 hours, which makes them ideal for northern gardeners above the 37th parallel. Choosing the wrong photoperiod type — planting a short-day variety up north — results in lush tops but tiny bulbs. Here is what matters most when selecting a batch.
Day-Length Classification
Check the product description for explicit “long-day” labeling. Intermediate or day-neutral varieties bulb under a wider range of daylight hours, but they often produce smaller storage onions in northern climates. Stargazer Perennials clearly marks the Red Baron sets as a long-day variety, which gives northern growers a predictable bulbing window.
Bulb Viability and Set Size
Larger marble-sized sets (approximately ½ to ¾ inch in diameter) tend to bolt faster than smaller sets, while dime-sized bulbs produce single large storage onions with less risk of early flowering. Open the package immediately upon arrival — if more than 10 percent of the bulbs are soft, desiccated, or moldy, return them before the return window closes.
Storage Longevity
Long-day varieties like Yellow Stuttgarter are bred for superior keeping qualities. If you plan to store onions through winter, look for varieties described as “storage onions” with firm, papery skins. Bunching types such as Tokyo Long White are harvested fresh and do not store long-term.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Red Baron Red Onion Sets | Sets | Long-term storage | 50-60 bulbs per 8 oz | Amazon |
| Yellow Stuttgarter Onion Sets | Sets | Versatile cooking | 50-60 bulbs per 8 oz | Amazon |
| Mixed Onion Assortment | Sets | Color variety | 40-60 bulbs per 8 oz | Amazon |
| 100 White Onion Bulbs | Sets | High quantity | 100 bulbs per bag | Amazon |
| Tokyo Long White Bunching | Seeds | Microgreens or scallions | ~33,600 seeds per 4 oz | Amazon |
In‑Depth Reviews
1. Red Baron Red Onion Sets
The Red Baron sets from Stargazer Perennials are explicitly labeled as a long-day variety, which removes any guesswork for northern gardeners tracking daylight hours. Each 8-ounce box holds 50 to 60 firm burgundy bulbs that landed in good condition according to most buyers, with one user reporting 45 out of 50 successfully bulbed in a raised bed.
The strong flavor profile makes these a solid choice for fresh salsas and grilling, and the storage life is competitive with the Yellow Stuttgarter. The package includes a growing guide, though some customers received a higher number of small shriveled sets than expected in earlier shipments.
Slightly more expensive per bulb than bulk white options, but the consistency of bulb size and the variety’s slow-bolt characteristic justify the premium for northern growers who need predictable timing.
What works
- Explicit long-day labeling removes photoperiod confusion
- High germination rate with strong bulb formation reported
What doesn’t
- Some packages contained excessive loose skins rather than bulbs
- Cannot ship to Idaho or Washington
2. Yellow Onion Sets for Planting — Stuttgarter
The Yellow Stuttgarter sets are classified as an intermediate-day variety, meaning they adapt to a wider range of latitudes than strict long-day types. This flexibility is valuable for gardeners near the transition zone where 14-hour days are borderline.
Customer reports describe healthy, hearty bulbs that established quickly, with one buyer planting in October and seeing nearly all sets sprout within three weeks. The flavor is mildly sweet, and the keeping quality is a standout feature — these are bred for long-term storage rather than immediate fresh use.
The main drawback is inconsistency: one negative review noted that over 80 percent of the sets arrived desiccated and crumbled, suggesting that quality control varies by harvest batch. The included growing guide is a helpful addition for beginners.
What works
- Intermediate-day classification suits transitional climates
- Excellent storage life for winter keeping
What doesn’t
- Batch quality inconsistency — some packages arrive dried out
- Cannot ship to Washington or Idaho
3. Mixed Onion Assortment — Red, White, Yellow
This mixed assortment combines red, white, and yellow varieties in a single 8-ounce package, giving you a color-varied harvest without buying three separate boxes. The mix includes intermediate, day-neutral, and long-day types, so germination success is less dependent on precise latitude.
Buyers consistently report high germination rates — one reviewer noted 100 percent sprouting within 10 days. The bulbs arrived firm and plump, which contrasts with the dry husks often found at local nurseries. The variety also supports harvesting young as scallions or letting bulbs mature fully.
The trade-off is the random color ratio: one customer noted the bag was heavily weighted toward yellow with only a few red onions. If you need a specific color ratio for cooking or pickling, this mix may not deliver the balance you expect.
What works
- High germination rate with firm, healthy bulbs
- Multiple colors from a single purchase
What doesn’t
- Color distribution is random and uneven
- Some bulbs arrived dried out in certain batches
4. 100 White Onion Bulbs for Planting
For gardeners who need a high bulb count for large beds or community plots, the Yunaksea white onion set bag offers 100 bulbs at a per-unit rate that is among the lowest in this roundup. The bulbs are marketed for full-sun exposure and moderate watering, matching standard onion care requirements.
Positive reviews describe vigorous growth and successful use in educational programs, with one Master Gardener using the bulbs for a preschool planting project. However, multiple negative reviews report that the package contained significantly fewer than 100 viable bulbs, with some bags holding mostly empty skins or soft, unusable sets.
The risk of receiving a substandard batch is higher here than with the Stargazer Perennials offerings, making this a gamble for precision-focused growers who need every bulb accounted for.
What works
- Lowest per-bulb cost for high-volume planting
- Bulbs grew well for most customers who received viable sets
What doesn’t
- Short count and empty skins reported in several batches
- Soft, non-viable bulbs arrived in some orders
5. Tokyo Long White Bunching Onion Seeds
This is the only true seed product in the roundup — a 4-ounce bag of heirloom, non-GMO Tokyo Long White Bunching seeds containing roughly 33,600 individual seeds. Unlike bulb sets, these are intended for direct sowing or microgreen production, with a maturity window of 65 to 100 days.
The Mountain Valley Seed Company brand is well-regarded for seed quality, and early germination reports are positive. The bunching variety produces scallion-style onions that do not form large bulbs, making this a poor choice for storage onion growers but an excellent option for fresh green onions or microgreens.
One review noted a low germination rate, which can happen with any seed lot, but the massive quantity means even a modest percentage yields plenty of plants. This product is best suited for gardeners who want scallions or microgreens rather than bulbing onions.
What works
- Extremely high seed count for the price
- Heirloom, non-GMO, open-pollinated genetics
What doesn’t
- Low germination rate reported in some batches
- Does not produce storage onions — scallion only
Hardware & Specs Guide
Bulb Set Size and Count
Onion sets are typically sold by weight (8 ounces), but the number of bulbs per package varies from 40 to 60 depending on the diameter of each set. Marble-sized sets (½ inch) produce the best single storage onions, while larger sets often bolt and produce flower stalks instead of bulbs. Count the bulbs immediately upon arrival to verify the advertised quantity.
Day-Length Classification
Long-day varieties bulb when daylight exceeds 14 to 16 hours, making them suitable for northern latitudes above the 37th parallel. Intermediate-day types adapt to 12 to 14 hours and are more forgiving for transitional zones. Short-day varieties require 10 to 12 hours and are best for southern growers. Check the label to match your region.
FAQ
What is the difference between onion sets and onion seeds?
How do I know if a variety is truly long-day?
Can I plant long-day onion sets in the fall?
What should I do if my onion sets arrive dried out?
Final Thoughts: The Verdict
For most northern gardeners searching for a long day onion seeds solution, the winner is the Red Baron Red Onion Sets because its explicit long-day labeling and strong storage life remove the two biggest sources of failure: photoperiod mismatch and early spoilage. If you want a mixed-color harvest from a single package, grab the Mixed Onion Assortment from Stargazer Perennials. And for high-volume scallion production or microgreen growing, nothing beats the seed count of the Tokyo Long White Bunching.