When To Plant Onions In Arkansas

Getting your onion planting timing right is the single most important factor for a succesful harvest. If you’re wondering when to plant onions in Arkansas, you’re already on the right track. This guide gives you the clear, simple steps to follow for big, beautiful bulbs.

Onions are a staple in Arkansas gardens, but they can be a bit picky about when they go in the ground. Plant them too early, and a late freeze can cause them to bolt (flower) too soon. Plant them too late, and they won’t have enough time to form large bulbs before our summer heat arrives. Let’s break down the perfect schedule.

Arkansas spans USDA Hardiness Zones 6b through 8a, which means our springs warm up at different times. Your specific location in the state is the key to perfect timing.

Understanding Onion Types: Day Length is Key

Before you plant, you must choose the right type of onion. Onions are categorized by the ammount of daylight they need to form bulbs:

Long-Day Onions: Need 14-16 hours of daylight. Best for northern Arkansas.
Short-Day Onions: Need 10-12 hours of daylight. Ideal for central and southern Arkansas.
Day-Neutral (Intermediate-Day) Onions: A flexible choice that forms bulbs with 12-14 hours of daylight. They perform well almost anywhere in the state.

Your Arkansas Planting Calendar

Onions can be grown from seeds, sets (small bulbs), or transplants. Transplants are the most common and reliable method here.

For Spring Planting (Primary Season)

Transplants & Sets: Plant them outdoors from late January through mid-March.
Seeds: For a head start, sow seeds indoors about 8-10 weeks before your intended outdoor planting date. This means starting seeds in December or early January.

The goal is to get them in the ground as soon as the soil is workable—not frozen or soggy. They can tolerate a light frost.

For a Fall Planting (Overwintering)

In southern Arkansas (Zone 8a), you can plant short-day onion varieties in October. They will establish roots, go dormant in winter, and then start growing vigorously very early in spring, often resulting in an earlier harvest.

Step-by-Step Planting Guide

Choose Your Variety: Pick based on your zone. For north AR: ‘Walla Walla’, ‘Yellow Sweet Spanish’. For south AR: ‘Texas Grano’, ‘Red Burgundy’. For all areas: ‘Candy’, ‘Super Star’ (day-neutral).
Prepare the Soil: Onions need loose, well-draining soil with lots of organic matter. Work in compost or aged manure. They prefer a soil pH between 6.0 and 6.8.
Plant Correctly: Space transplants or sets 4-6 inches apart in rows 12-18 inches apart. Plant them just deep enough so the base is covered, with the top point peeking out. If using sets, don’t bury them too deep.
Water and Feed: Water immediately after planting. Keep the soil consistently moist but not waterlogged. Feed with a nitrogen-rich fertilizer every few weeks until bulbs begin to form.
Weed Carefully: Onions have shallow roots. Hand-pull weeds regularly so they don’t have to compete for nutrients.

Common Mistakes to Avoid

Even experienced gardeners can make a few errors with onions. Here’s what to watch for:

Planting the Wrong Type: Putting a long-day onion in southern Arkansas will mean it never gets enough daylight to form a proper bulb.
Poor Soil Preparation: Heavy, compacted clay soil will stunt growth and lead to small, misshapen onions.
Overcrowding: Giving onions to little space is a common mistake. They need room to expand underground.
Inconsistent Watering: Letting the soil dry out completely, then flooding it, can cause bulbs to split or become bitter.

Harvesting and Curing Your Crop

Knowing when to harvest is as important as knowing when to plant. Here are the signs:

The tops (leaves) will turn yellow and begin to fall over naturally.
Once about half the tops have fallen, gently push over the remaining ones to stop growth.
A week later, carefully lift the bulbs from the soil with a garden fork.

Curing is Essential: Lay the bulbs in a single layer in a warm, dry, airy place out of direct sun—like a garage or covered porch. Let them cure for about two to three weeks until the necks are tight and the outer skins are papery. This step ensures they store for months.

FAQ: Your Arkansas Onion Questions Answered

Can I plant onions from the grocery store?

It’s not recommended. Grocery store onions are often treated to prevent sprouting and may be varieties unsuited for our climate. It’s best to buy seeds, sets, or transplants from a garden center.

What are the best companion plants for onions in my garden?

Onions do well near carrots, beets, lettuce, and members of the cabbage family. Their scent can help deter some pests. Avoid planting them too close to peas or beans, as they can inhibit each others growth.

Why are my onions so small?

Small onions are usually caused by one of three things: incorrect day-length variety, planting too late, or insufficient nitrogen early in the growing season. Double-check you’re using the right type for your zone.

How do I store my harvested onions for the long term?

After curing, store them in a cool, dry, dark place with good air circulation. Mesh bags, old pantyhose, or a well-ventilated bin work great. Check them periodically and use any that feel soft.

Getting your timing right with onions in Arkansas sets the stage for a rewarding harvest. By choosing the correct day-length variety and getting them in the ground at the right moment—late winter to early spring—you give your plants the best possible start. With a little preparation and care, you’ll be pulling up plump, flavorful onions to enjoy for seasons to come.