I’ve had several readers write to me lately asking me if transplants would be alright shipped across country. They also wanted to know how long the onions would keep.
Onion sets are a great way to get a head start on growing onions These tiny onion bulbs allow you to bypass the seed starting process and plant onions that are ready to grow into full-sized bulbs However, you may find yourself with extra onion sets that you need to store until your growing season begins. Properly storing onion sets is important to keep them fresh and viable for planting. This complete guide will teach you everything you need to know about storing onion sets for planting.
What are Onion Sets?
Before we dive into storage methods, let’s make sure we all understand what onion sets are. Onion sets are small onion bulbs that are planted directly in the garden. They are grown the year prior from seed and overwintered. In the spring, the onion sets are sold for gardeners to plant. Because they have already begun growing, onion sets mature faster than onions grown from seed. This allows you to harvest green onions or full-sized bulbs weeks earlier.
Onion sets are available in most types of onions including yellow white, and red. When shopping for onion sets look for bulbs that are free from mold, damage, and rot. The sets should be firm, dry, and heavy for their size. Storing onion sets properly will help maintain this freshness.
Why Store Extra Onion Sets?
There are a few scenarios that may result in you needing to store leftover onion sets.
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You purchased too many onion sets and weren’t able to get them all planted. It’s easy to buy more than you need when they are on sale early in the season.
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You grew your own onion sets last year and have an excess amount in storage from your harvest. Homegrown sets often result in high yields.
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You ordered onion sets by mail order earlier in the year but couldn’t plant them immediately after receiving them. Transplants shipped by mail require temporary storage.
No matter the reason, it’s important to know how to properly store onion sets to keep them in good condition for planting when the time comes. Using the right storage methods can keep onion sets fresh for up to 2 months.
Step 1 – Cure Onion Sets After Purchase
If you have purchased onion sets from a garden center or received shipped sets, the first step is to cure them. Curing allows the skin to further dry and heal any nicks or damage that may have occurred during handling. To cure sets, simply spread them out in a single layer indoors at room temperature out of direct sunlight. Allow them to sit undisturbed for about 2 weeks. Sunlight can cause sprouting which you want to avoid at this stage. However, air circulation will prevent rotting during the curing process.
Step 2 – Choose the Right Storage Method
Once cured, it’s time to move the onion sets into long term storage until you are ready to plant them. There are a few different methods that all work well for storing onion sets.
a. Hang Sets in Mesh Bags
Hanging onion sets in mesh bags is one of the most common and effective storage methods.
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Place the sets in mesh bags like those used for storing produce. Onion sets sold in bulk at most garden centers come packaged in these ideal mesh bags.
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Hang each bag in a cool, dry place with good air flow. The increased air circulation will prevent mold and rot.
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Ideal places to hang bagged sets are a garage, shed, basement, or even a closet. Just avoid areas that get too hot, humid, or wet.
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Make sure to check the stored onion sets occasionally for any moisture or signs of rotting bulbs. Remove any bad sets immediately to prevent rot from spreading.
b. Store Sets in Shallow Trays
Another good approach is storing the onion sets spaced out in shallow trays or boxes.
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Spread the sets in a single layer in the tray or box, making sure none of the bulbs are touching each other.
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Place the trays in a cool, dry location out of direct sunlight. A mudroom, enclosed porch, or garage typically provides suitable conditions.
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Use a fan to keep air circulating around the trays if needed. Airflow is important to prevent rot and mold.
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Check the onion sets every week or so and remove any that are showing signs of deterioration. Just a few rotten sets can ruin the whole batch.
c. Refrigerate Sets in Perforated Plastic Bags
You can also refrigerate onion sets loose in perforated plastic bags:
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Place the onion sets in plastic bags designed for produce. Make sure the bags have perforations for airflow.
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Keep the bags in the refrigerator set to around 40 degrees Fahrenheit. The low temperature will induce dormancy and extend freshness.
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Check the stored sets periodically and remove any with moisture or damage. Refrigeration can cause increased humidity.
While refrigeration requires more attentiveness, it keeps the onions dormant for longer versus other methods.
Step 3 – Plant Onion Sets Quickly After Storage
Onion sets will keep for 1-2 months using proper storage methods. However, like any living thing, their quality slowly declines over time. For best results, try to plant your stored onion sets as soon as your garden is ready. Here are some tips for a successful planting after storage:
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Inspect the sets closely and discard any with signs of rot or damage before planting. Bad sets can introduce disease into your garden.
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Set the plants deep, with just the tip exposed above ground. This prevents the bulbs from being pushed out of the ground as they grow.
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Space the onion sets 4-6 inches apart in all directions. They need sufficient room to grow into mature bulbs.
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Water the planting area before and after planting if the soil is dry. Consistent moisture will encourage good root establishment.
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Adding a balanced fertilizer when planting will fuel growth. An all-purpose vegetable fertilizer works well.
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Cover newly planted onion sets with a floating row cover to protect from insect pests. Remove once they start growing vigorously.
Storing onion sets properly will keep them in prime, plantable condition so you can get your onion crop off to its earliest start. Just be sure to get them in the ground as soon as possible once your soil is workable.
Frequently Asked Questions About Storing Onion Sets
How long do onion sets last in storage?
Most onion sets will keep for 1-2 months if stored properly in a cool, dry location with good air circulation. Refrigeration can potentially extend their shelf life longer. However, their quality still diminishes over time so plant them as soon as you can.
Can you freeze onion sets for storage?
Freezing is not recommended for storing onion sets. The freezing process will damage the bulbs, making them rot quickly when thawed. It’s best to use one of the methods above that rely on cool, dry conditions without freezing.
What causes onion sets to rot in storage?
The main causes of rotting onion sets during storage are moisture, humidity, lack of air circulation, and storing at too warm of a temperature. Ensure your storage location is cool and dry with ample airflow. Check frequently for any rotting bulbs and remove them immediately. Even minor moisture on the surface can allow rot to take hold under poor storage conditions.
Can you store onion sets from season to season?
It is not recommended to store onion sets long term over multiple seasons. Onion sets are only meant to be stored for a portion of one season until you can get them planted. Storing them long term usually results in complete loss of viability and rot. For extended storage, mature, cured dry onions are a better option.
How can you tell if stored onion sets are still good?
Check onion sets for firmness and mold-free, intact outer skins. Avoid sets with moisture, sunken or mushy areas, or any sign of sprouting. Good onion sets may show some outer peel loosening but should still feel solid when squeezed gently. Sniff the onion sets for any foul odors which can indicate rot. Discard any questionable sets to be safe.
Conclusion
Having a stash of onion sets ready for planting is a great way to get your onion crop started early. With the right storage methods, you can keep extra onion sets in optimal condition for 1-2 months. Look for a cool, dry spot that allows for plenty of air circulation. Inspect the sets frequently and remove any with signs of rot. With the proper care, your onion sets will be fresh and ready to thrive when the planting season arrives. Just be sure to get them in the ground as soon as you can for best results.
Storing Onion Sets – Step 2
Hang the mesh bag in a cool, dry place with good air circulation. Basements arent ideal locations, as they tend to be damp, which can cause rot when storing onion sets. Instead, consider using a semi-heated or connected garage, an attic, or even an uninsulated closet.
They Know How to Ship
Companies that specialize in shipping onions — know how to ship in a manner that your onions will get you in perfect condition. Unless something goes very wrong and unexpected — your transplants will be in great condition when they arrive at your door.
To keep them as good as new until you can plant them here’s what you do:
The minute they arrive at your door
- remove them from the box;
- take the rubber bands off the bunches;
- spread them out so the air can get to them. (I like to spread them out in shallow boxes.)
Keep them out of direct sunlight. I have in the past put mine in the garage, but I prefer to keep them in my mud room/enclosed porch where I can have a fan running 24/7 if the weather is warm enough to make it “stuffy” in my porch.