Customer Service Hours
Mon-Fri 8-4 MST
Features
Family
Alliaceae
Native
Exists only in cultivation
Life Cycle
Annual
Plant Height
3" to 4" round bulb
Further Information
Growing Conditions
Frost Tolerant
About Red Amposta Bulb Onion Seeds
Allium cepa
3"–4" reddish- purple, globe-shaped, sweet onions.
Planting Onion
Plant Spacing
A group of 2 seeds every 4"
Light Required
Full sun
Plant Height
3" to 4" round bulb
Planting Depth
¼"
Coverage & Planting Details
| Coverage | This packet sows up to 22 feet. |
|---|---|
| Row Spacing | 12"–16" |
| Seed Depth | ¼" |
| Seed Spacing | A group of 2 seeds every 4" |
| Thinning | When 2" tall, thin to 1 every 4" |
| Germination | 7–15 days |
| Start Indoors | RECOMMENDED. 10 to 12 weeks before your average last frost date. Transplant outdoors 4 to 6 weeks before your average last frost date. The earlier the start, the bigger the bulb. Ideal soil temperature is 60°–85°F. |
| Direct Sow | 4 to 6 weeks before your average last frost date, or as soon as soil can be worked; when soil temperature is at least 45°F. |
| Growing & Harvesting | When onion tops have fallen over and turned yellow or brown, they are ready for harvest. Harvest in the morning, lifting onions with a garden fork. Dry them in the garden in the sun for 2 to 3 days, lightly covering the bulbs with straw, or the tops of other onions to prevent sunscald. Cure onions for 3 to 7 days in a dry area with good air circulation. Once dry, cut the roots to 1/4", and the greens to 1" to create a seal, preventing decay. |
Find Your Frost Date & Grow Zone
Average First Frost Date
October 19
Average Last Frost Date
May 19
Your Hardiness Zone is
5b
Send Your Recommendation
Total 5 star reviews: 7 Total 4 star reviews: 3 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 1
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Rating
Which best describes you as a gardener?
11 reviews
- Debi U.Verified BuyerRated 4 out of 5 stars4/15/26Growing well
The seeds were slow to germinate but doing well. I started them inside and will plant soon. I’m in zone 4b so still not ready to plant out.
Which best describes you as a gardener? IntermediateBIBotanical Interests4/15/26Hey Debi,
We're so glad to hear your Red Amposta Bulb Onion Seeds are doing well also! Your photo is great! You're going to have a great onion harvest this year. You'll have strong transplants ready to go when your weather warms up! These red beauties are going to produce some amazing sweet onions with that gorgeous deep color for your kitchen. Keep on growing 🌻️
- MarjorieVerified BuyerRated 5 out of 5 stars4/4/26Red Amposta Onion Seed!Intermediate day onionss or neutral day onions.
I ordered this in Mid January & winter-sown on 2/07/26. Now, ready to be transplanted into the ground. 💯 %Germination . Highlands Ranch, COLORADO Zone 6a. This variety is great for Intermediate day or neutral day latitude from 32-42.
Which best describes you as a gardener? IntermediateBIBotanical Interests4/4/26Hey Marjorie,
We're absolutely thrilled to hear about your perfect 100% germination rate with your Red Amposta Bulb Onion Seeds! It sounds like your winter-sown timing was spot on, and how exciting that they're already ready for transplanting. You clearly know your stuff about intermediate and neutral day varieties - these Red Ampostas are going to do fantastic in your Zone 6a Colorado garden! Here's to a wonderful harvest of beautiful red onions this season. Keep on growing 🌻️
- PatriciaRated 5 out of 5 stars3/25/265 Stars
Great
- Laura R.Verified BuyerRated 5 out of 5 stars2/18/26Wow, Robust
Wow, these Red Amaposta seedlings were robust and are huge compared to the other onion variety I planted! Great seed!
Which best describes you as a gardener? IntermediateBIBotanical Interests2/20/26Hey Laura,
Wow, that's incredible! We're absolutely thrilled to hear your Red Amposta onions are showing off their robust nature right from the start! There's nothing quite like seeing those seedlings take off and outperform your expectations - it sounds like they're really making a statement in your garden! Red Amposta onions are known for their vigorous growth, and it sounds like you're getting the full experience. We can't wait to see how massive these beauties get as they continue to mature! Thank you for choosing us and for sharing this fantastic growing update with us. Keep on growing 🌻️
- Katie L.Verified ReviewerRated 5 out of 5 stars1/9/26Fantastic start
17 out of the 18 cells I planted germinated. I'm really excited to see how these do! I'll update if I can later after growing is complete.
Which best describes you as a gardener? BeginnerBIBotanical Interests1/13/26Hey Katie,
Thank you so much for taking the time to share your fantastic germination results with our Red Amposta Bulb Onion Seeds! We're absolutely thrilled to hear that 17 out of 18 cells germinated - that's incredible success! The Red Amposta variety really is something special and we're so excited for you to experience the full growing journey. We'd love to hear how they turn out for you later in the season! Thank you for choosing us and for sharing your growing success with us. Keep on growing 🌻️