Nevada’s varied climate zones require careful attention to elevation when scheduling your onion planting. Knowing the best time to plant onions in Nevada can mean the difference between a bumper crop and a disappointing harvest.
Onions are cool-season crops that need specific day lengths and temperatures to bulb properly. In Nevada, you have to work with both the desert heat and the mountain cold.
This guide breaks down exactly when to plant onions in every part of the Silver State. We’ll cover soil temps, variety selection, and step-by-step timing.
Understanding Nevada’s Growing Zones For Onions
Nevada spans USDA hardiness zones 4 through 9. That’s a huge range. Las Vegas is zone 9a, while Elko sits in zone 4b.
Your elevation is the biggest factor. Lower elevations mean hotter summers and milder winters. Higher elevations bring late frosts and shorter growing seasons.
Onions need about 90 to 120 days from transplant to harvest. They also require 10 to 14 hours of daylight to form bulbs, depending on the variety.
Low Elevation Zones (Below 4,000 Feet)
This includes Las Vegas, Laughlin, and parts of the Moapa Valley. Winters are mild, summers are scorching.
- Average last frost: Mid-February to early March
- Average first frost: Mid-November to early December
- Growing season: 200+ days
You can plant onions here in late winter. The key is to get them established before the intense heat arrives in June.
Mid Elevation Zones (4,000 To 6,000 Feet)
Reno, Carson City, Fallon, and Winnemucca fall here. Winters are cold, summers are warm but not extreme.
- Average last frost: Late April to mid-May
- Average first frost: Mid-October to early November
- Growing season: 120 to 160 days
Spring planting is standard here. You’ll need to start seeds indoors or buy transplants.
High Elevation Zones (Above 6,000 Feet)
Elko, Ely, and Tonopah are in this group. Short summers and cold nights are the norm.
- Average last frost: Late May to mid-June
- Average first frost: Early to mid-September
- Growing season: 80 to 100 days
You need fast-maturing onion varieties here. Even a slight delay in planting can ruin the crop.
Best Time To Plant Onions In Nevada
Now let’s get specific. The Best Time To Plant Onions In Nevada depends entirely on your location and whether you’re using seeds, sets, or transplants.
For Low Elevations (Las Vegas, Laughlin)
Plant onion sets or transplants from January 15 to February 15. This gives them time to grow before the heat hits.
If you’re starting from seed, sow indoors in late November or early December. Transplant outdoors in January or February.
Onions need consistent moisture. In the desert, you’ll water more often. Mulch helps retain soil moisture and keeps roots cool.
For Mid Elevations (Reno, Carson City)
Plant onion sets or transplants from April 1 to May 1. Wait until soil temperatures reach at least 50°F.
Start seeds indoors 8 to 10 weeks before your last frost date. For Reno, that means sowing seeds in late February or early March.
Hardening off is important. Gradually expose transplants to outdoor conditions over a week before planting.
For High Elevations (Elko, Ely)
Plant onion sets or transplants from May 15 to June 1. The soil must be workable and frost danger should be past.
Start seeds indoors in late March or early April. Use a heat mat to speed germination.
Consider using black plastic mulch to warm the soil. This can give you a crucial head start in short seasons.
Choosing The Right Onion Variety For Nevada
Onions are classified by day length. This determines when they start forming bulbs. Pick the wrong type, and you’ll get tiny onions or no bulbs at all.
Short-Day Onions
These need 10 to 12 hours of daylight. They’re best for low elevations in southern Nevada.
- Texas SuperSweet
- Red Creole
- Yellow Granex (Vidalia type)
- White Bermuda
Plant these in late winter. They’ll bulb in late spring before the heat arrives.
Intermediate-Day Onions
These need 12 to 14 hours of daylight. They work well in mid elevations like Reno.
- Candy
- Red Candy Apple
- Super Star
- Cabernet
These are versatile and store reasonably well. They bulb in early to mid-summer.
Long-Day Onions
These need 14 to 16 hours of daylight. They’re essential for high elevations in northern Nevada.
- Yellow Sweet Spanish
- Walla Walla
- Red Wethersfield
- White Sweet Spanish
These onions bulb in late summer. They need the long days of June and July to develop properly.
Step-By-Step Planting Guide
Follow these steps for success no matter where you live in Nevada.
Step 1: Prepare The Soil
Onions need loose, well-draining soil with a pH between 6.0 and 7.0. Nevada soil is often alkaline and compacted.
Work in 2 to 3 inches of compost or well-rotted manure. Add a balanced fertilizer like 10-10-10 at a rate of 1 pound per 100 square feet.
Remove rocks and break up clods. Onion roots are shallow and need room to spread.
Step 2: Choose Your Planting Method
You have three options: seeds, sets, or transplants.
- Seeds: Cheapest but slowest. Start indoors 8 to 10 weeks before planting. Direct sowing is risky in Nevada due to heat and cold.
- Sets: Small bulbs grown last year. Easy but more prone to bolting. Good for beginners.
- Transplants: Started from seed by a nursery. Most reliable for timing. Slightly more expensive.
For most Nevada gardeners, transplants or sets are the best choice. They save time and reduce risk.
Step 3: Plant At The Right Depth
Plant onion sets and transplants 1 inch deep. Space them 4 to 6 inches apart in rows 12 to 18 inches apart.
If you’re growing for storage, space them 4 inches apart. For large bulbs, go with 6 inches.
Firm the soil around each onion. Water thoroughly after planting.
Step 4: Water Consistently
Onions need about 1 inch of water per week. In Nevada’s dry climate, you may need more.
Water deeply once or twice a week. Shallow watering encourages shallow roots.
Stop watering when the tops start to fall over. This signals the bulbs are maturing.
Step 5: Fertilize Regularly
Onions are heavy feeders. Apply a nitrogen-rich fertilizer every 2 to 3 weeks during the growing season.
Use a side dressing of ammonium sulfate or blood meal. Avoid high-nitrogen fertilizers after bulbs start forming.
Too much nitrogen late in the season can cause thick necks and poor storage.
Common Onion Planting Mistakes In Nevada
Even experienced gardeners make errors. Here are the most common ones to avoid.
Planting Too Early Or Too Late
Planting too early exposes onions to frost damage. Planting too late means they won’t mature before heat or frost arrives.
Check your local frost dates. Use a soil thermometer to confirm the ground is warm enough.
Using The Wrong Day-Length Variety
Short-day onions planted in northern Nevada won’t bulb properly. Long-day onions in southern Nevada will bulb too early.
Always match the variety to your latitude. Ask your local extension office for recommendations.
Overwatering Or Underwatering
Onions need consistent moisture but not soggy soil. Overwatering leads to rot. Underwatering stunts growth.
Use a moisture meter or check soil 2 inches down. Water when it feels dry.
Ignoring Soil Preparation
Nevada soil is often hard and alkaline. Onions struggle in compacted ground.
Take time to amend the soil before planting. It makes a huge difference in bulb size.
Harvesting And Storing Onions In Nevada
Knowing when to harvest is just as important as knowing when to plant.
When To Harvest
Onions are ready when the tops fall over and turn yellow. This usually happens 90 to 120 days after planting.
Don’t wait too long. Overripe onions can split or rot in the ground.
Gently pull or dig them up on a dry day. Brush off excess soil but don’t wash them.
Curing Onions
Curing is essential for storage. Spread onions in a single layer in a warm, dry, well-ventilated area.
Leave them for 2 to 3 weeks. The necks should be completely dry and the outer skin papery.
Cut off the tops 1 inch above the bulb and trim the roots. Store in a cool, dark place.
Storage Tips
Store cured onions in mesh bags or crates. Keep them at 32 to 40°F with low humidity.
Check regularly for soft or sprouting onions. Remove any bad ones to prevent spoilage.
Sweet onions don’t store as long as pungent varieties. Eat them first.
Frequently Asked Questions
Can I Plant Onions In The Fall In Nevada?
Yes, in low elevations like Las Vegas, you can plant short-day onions in September or October for a spring harvest. In higher elevations, fall planting is too risky due to freezing temperatures.
What Is The Best Onion For Northern Nevada?
Long-day varieties like Yellow Sweet Spanish or Walla Walla work best. They need the long daylight hours of summer to form bulbs properly.
How Deep Should I Plant Onion Sets?
Plant sets 1 inch deep with the pointed end up. Cover them lightly with soil and water well.
Do Onions Need Full Sun In Nevada?
Yes, onions need at least 6 to 8 hours of direct sunlight daily. In southern Nevada, some afternoon shade can help prevent heat stress.
Can I Grow Onions From Grocery Store Bulbs?
It’s possible but not recommended. Grocery store onions may carry disease or be treated to prevent sprouting. Use certified seed or sets from a garden center.
Final Tips For Success
Onions are one of the most rewarding crops you can grow in Nevada. They store well and add flavor to almost any dish.
Start small if you’re new. A 10-foot row of onions can yield 20 to 30 pounds of bulbs.
Keep a garden journal. Note your planting dates, variety, and harvest results. This helps you refine your timing each year.
Talk to local gardeners. Nevada’s Master Gardener program is an excellent resource. They know the quirks of your specific area.
With the right timing and a little care, you’ll be pulling beautiful onions from your Nevada garden. The best time to plant onions in Nevada is when you’ve matched your variety to your elevation and prepped your soil properly.
Get your sets or transplants ready. Check your frost dates. And enjoy the satisfaction of homegrown onions that taste far better than anything from the store.