How To Tell If Onions Are Ready To Harvest

Knowing how to tell if onions are ready to harvest is the key to getting the best flavor and storage life from your crop. If you pick them too early, the bulbs will be small; too late, and they might not store well. This guide will walk you through the clear, physical signs that your onions are mature and waiting to be pulled from the ground.

Onions are a patient gardener’s reward. They take a long time to grow, often over 100 days from planting. But that wait is worth it when you have a basket full of firm, flavorful bulbs. The trick is knowing exactly when to stop watering and start lifting.

Onions send unmistakable signals when they’re done growing. Unlike some vegetables, you can’t judge by size alone. Instead, you need to watch for a specific sequence of changes in the plant’s top growth. This process is called “bulbing” and it’s your main clue.

The Top Signs of Onion Maturity

Look for these three things happening in your onion patch. When you see them, harvest time is near.

Neck Softening: The area where the leaves meet the bulb (the neck) will start to feel soft and lose its rigidity. If you gently squeeze it, it won’t feel sturdy anymore.
Foliage Collapse: About half to three-quarters of the green tops will fall over. They’ll bend at the neck and lay down on the soil. This is the plant’s way of saying it’s finished growing.
Leaf Color Change: The green leaves will begin to turn yellow and then brown, starting from the tips and moving down. This is normal and indicates the plant is diverting its last energy into the bulb.

Timing and Onion Types

Not all onions behave the same. The type you planted affects the timing.

Short-Day Onions: These varieties start forming bulbs when daylight lasts 10-12 hours. They’re best for southern latitudes. They often mature faster, sometimes in early to mid-summer.
Long-Day Onions: These need 14-16 hours of daylight to bulb and are ideal for northern gardens. They typically mature in mid to late summer.
Day-Neutral Onions: These flexible varieties form bulbs regardless of day length and can be grown in many regions. Their maturity is more consistent across locations.

Always check your seed packet for the “days to maturity” estimate. Use it as a guideline, but let the plant’s physical signs be your final authority.

A Step-by-Step Harvest Readiness Check

Follow this simple process each day once you think your onions are close.

Walk through your onion bed and look for tops that have fallen over. Don’t worry if they don’t all go down at once.
Gently squeeze the neck of a few plants that have flopped over. It should feel soft and pliable, not thick and firm.
Brush away a little soil from the shoulder of a bulb. The very top of the bulb should be visible and the outer skin will have a papery, dry look.
If most plants show these signs, stop watering. This is crucial for good curing. Let them sit in the dry soil for about a week.

What About Green Onions?

Green onions, or scallions, are a different story. You harvest these before they form a large bulb. Simply pull them when the green tops are the thickness and height you desire. They are always harvested immature.

Common Mistakes to Avoid

Even experienced gardeners can make a few errors when judging onion readiness.

Harvesting at First Topple: When the first few tops fall, wait. Let most of the crop signal it’s ready. Picking too early means smaller bulbs that won’t store.
Continuing to Water: Once tops are down, extra water can rot the bulbs or cause the outer skins to split. Let the soil dry out.
Bending Tops Yourself: Never bend the green tops over by hand to force maturity. This can damage the neck and invite rot. Let the plant do it naturally.
Ignoring the Weather: If heavy rain is forcasted right when you need to stop watering, you might harvest a bit early to prevent rot. Cure them thoroughly instead.

The Harvest and Curing Process

Knowing when to harvest is only half the job. Proper handling right after is what gives you onions that last for months.

Choose a dry, sunny morning for harvest. Gently loosen the soil with a fork, being careful not to pierce the bulbs, and lift them out.
Lay them in a single layer right on the dry garden soil for 1-2 days, if weather permits. This sun-bath helps kill rootlets and starts the drying.
Move them to a well-ventilated, shaded, and dry place. A covered porch, garage rack, or shed is perfect. Spread them out so air can circulate all around.
Let them cure for 2-4 weeks. The necks should become completely tight and dry, and the outer skins rustle like paper. The roots will shrivel up.

How to Know When Curing is Complete

You’ll know your onions are fully cured and ready for storage when you can’t feel any moisture at the neck. It will be completely closed and tight. The outer skin will be fully papery and uniform in color. When you trim the roots, they should snap off cleanly without any tugging.

Storing Your Harvested Onions

After curing, trim the tops down to about 1 inch and clip the dried roots. Store them in a cool, dark, and dry place with good air flow. Mesh bags, old pantyhose, or slatted crates are ideal. Check them occasionally and use any that feel soft first.

FAQ: Onion Harvest Questions

Can you leave onions in the ground too long?

Yes, you can. If left in wet ground after maturity, they are prone to rot or secondary root growth, which ruins them for storage. In very dry ground, they might become sunburned or overly dry.

What if my onion tops haven’t fallen over?

Sometimes, especially in cool, wet seasons, tops are slow to fall. If the bulbs look full and the necks are soft, you can carefully lift them and begin the curing process. They may just need a little nudge.

Why are my onions flowering?

A flower stalk, or “bolting,” is usually caused by stress like temperature swings. Once an onion bolts, it focuses energy on seed, not the bulb. Harvest bolted onions immediately and use them soon, as they won’t store well.

How long after onions fall over do you harvest?

After most tops have fallen, stop watering and wait about 7-10 days for the bulbs to finish maturing in the dry soil. Then, lift them for curing.

Can you eat onions right after harvest?

Absolutely! Freshly pulled, uncured onions are delicious and often more juicy. Just remember they have a higher water content and need to be used within a few weeks, unlike cured storage onions.

Learning how to tell if onions are ready to harvest takes a little observation, but it’s a simple skill. Watch for the tops to fall and the necks to soften. Then, stop watering, lift carefully, and cure them thoroughly. With this knowledge, you’ll enjoy homegrown onions from your garden long into the winter. There’s nothing quite like reaching into your own stash of onions for a meal.