GardenOnion variety
Red Mountain Onion
✓ In your garden
Red Mountain is a red long day onion, ready in about 107 days. It’s a long-day onion — bulbs up in the North (roughly above 37°N) on long summer days. Day length is the make-or-break for onions — pick the wrong type for your latitude and the bulbs stay small. Start from seed or sets in early spring.
“A bulb onion — match the type to your latitude.”
Growing basics — shared by every onion
Red Mountain grows like any other onion. The full picture — how deep to plant, spacing, feeding, pests, harvest — lives on the Onion page so it's maintained in one place.
- Sun
- Full Sun
- Spacing (in row)
- 3–4 in
- Row spacing
- 12–18 in
- Planting depth
- 1–1.5 in
- Soil pH
- 6–7
- Water
- Moderate
What is Red Mountain good for?
- CookingSautéed, roasted, raw. Great
- StoringPungent storage types cure and keep for months; sweet types (Walla Walla, Vidalia, 1015Y) don’t — eat those within weeks. Skip it
- Fresh & rawMilder and sweet types shine raw. Great
From how it grows — kitchens vary.
What Red Mountain is known for
Fedco Seeds describes this as:
- keeps a long time after picking
That is the company selling the seed, describing its own product. True, and worth weighing as such.
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Want the full 10/50/90% odds + nearest stations? Open the frost tool →When to plant Red Mountain in your zone
Zone 6bGreenhouse or cover on: your start slides ~4 weeks earlier and your harvest stretches ~3 weeks later (shown striped).
Planting seeds straight in the ground only works where the season's long and warm — most gardeners start seeds indoors or buy young plants, or you'd pick your first tomato right as frost hits.
Comfortable — first ripe fruit lands around early Jun, well before your typical frost (~late Oct).
- Start seeds indoors
- mid Feb – mid Feb
- Picking
- early Jun – late Jun
Typical dates for zone 6b — set your zone or ZIP above for yours.
What to plant near Red Mountain — and what to keep away
-
CarrotsTrialed
Interplanted onions confused carrot rust fly in some trials and did nothing in others. Worth a try, not a bet.
-
BeetsTraditional
Chart canon, both directions.
-
Cabbage familyTraditional
Old chart pairing; both hold cool-season beds.
-
LettuceTraditional
On the classic charts — lettuce's own row lists onions.
-
TomatoTraditional
Chart canon says onions and garlic make good tomato neighbors. No trials to point at, no conflict either.
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BeansTraditional
The most consistent 'no' in companion planting. Unproven, unanimous.
-
PeasTraditional
Same flag as beans — every chart agrees.
The badge is the honesty. Trialed = a published field trial · Practical = a real mechanism · Traditional = companion-chart lore. These pairings hold for every onion.
Pairings compiled from University of Minnesota Extension, West Virginia University Extension.
Growing Red Mountain — the things that trip people up
- Match the type to your latitude: long-day onions for the North, short-day for the South, intermediate in between — this is the single biggest factor in whether you get big bulbs.
- Onions are shallow-rooted and weak against weeds. Keep them weeded and evenly watered, ease off water as the tops fall over, then cure the bulbs in a dry, airy spot before storing.
Red Mountain onion at a glance
| Type | Long Day |
|---|---|
| Days to ripe | 107 days after you plant it outside |
| Color | Red |
Extra fields from seed-catalog listings and university growing guides. Days to ripe and disease resistance shift with your climate and seed source — double-check with your local extension office before you buy.
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Common questions about Red Mountain
How long does Red Mountain take to grow?
About 107 days from sowing. Start seed or sets in early spring for summer bulbs.
Will Red Mountain bulb where I live?
It’s a long day onion, so it bulbs best in the northern US. Match the day-length type to your latitude for full-size bulbs.
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