Growing candy onion plants is a rewarding way to enjoy the sweetest, mildest onions right from your backyard. These hybrid beauties need full sun, well-draining soil, and consistent watering to develop their massive, round bulbs. With the right care and a little patience, you will harvest deliciously sweet onions perfect for salads, grilling, and fresh eating.
Have you ever bitten into a raw onion and wished it tasted more like a sweet apple than a spicy bulb? That is exactly why candy onion plants are taking the gardening world by storm. If you love the idea of harvesting massive, sweet onions right from your backyard, you are in the right place. Growing candy onion plants is easier than you might think. These onions are famous for their mild, sweet flavor. They completely lack the harsh bite of standard yellow onions. Whether you are a beginner or a seasoned pro, this guide will walk you through everything you need to know to grow a bumper crop of these delicious, sweet beauties.
Key Takeaways
- Candy onions are day-neutral: They can grow in most climates regardless of daylight hours, making them highly versatile.
- Start from sets or transplants: While you can use seeds, sets and transplants yield larger, sweeter bulbs much faster.
- Soil quality is crucial: Loose, well-draining soil prevents rot and allows the bulbs to expand easily.
- Water consistently: Sweet onions need steady, even moisture to develop their signature mild flavor.
- Harvest when tops fall: Wait for the green stalks to naturally topple over before pulling your onions.
- Cure before storing: Always dry the bulbs in a warm, airy spot to extend their shelf life.
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What Makes Candy Onion Plants Special?
Candy onions are a hybrid variety. They were created by crossing a standard yellow onion with a sweet Spanish onion. The result is a massive, round bulb with pale yellow skin and a wonderfully mild taste. They are incredibly versatile in the kitchen. You can eat them raw on burgers, caramelize them for French onion soup, or grill them to perfection.
A Sweet Hybrid
The candy onion was specifically bred to be a super-sweet variety. Because they have such a high water content and low pyruvic acid, they are practically tear-free when you cut them. Pyruvic acid is the compound that makes you cry while chopping regular onions. With candy onions, you get all the onion flavor without the eye-stinging burn.
Day-Neutral Advantage
One of the best things about candy onion plants is that they are day-neutral. Onion varieties are usually divided into short-day, intermediate-day, and long-day categories based on how much sunlight they need to form bulbs. Short-day onions need the long days of winter to bulb, while long-day onions need the endless daylight of northern summers. Day-neutral candy onions do not care. They will form bulbs successfully in almost any climate, making them the perfect choice for gardeners everywhere.
When and How to Plant Candy Onion Plants
Timing is everything when it comes to onions. You want to give your candy onions plenty of time to grow green tops before they start forming bulbs. The more energy the green tops produce, the bigger the bulb will be.
Choosing Your Starting Method
You can start candy onion plants from seeds, sets, or transplants. Growing from seed takes the longest time, but it gives you the strongest plants. If you want the fastest route to a sweet harvest, learning how to plant onion sets is a great option. Sets are tiny, dormant bulbs that you push into the soil. Transplants are small seedlings that give you a head start on the season. For those starting from seed, understanding onion seeds when to plant is crucial for timing your garden perfectly.
Best Time to Plant
You should plant candy onion plants as soon as the soil can be worked in the spring. If you live in a warmer climate, you can also plant them in the fall for an early summer harvest. The soil temperature should be at least 40°F for sets and transplants, and 50°F for seeds.
Spacing and Depth
Proper spacing is vital for growing large bulbs. Plant your sets or transplants about one inch deep, making sure the tip of the onion is just barely poking out of the soil. Space them four to six inches apart in rows that are twelve to eighteen inches apart. If you are growing them in raised beds, you can space them a bit closer together.
Preparing the Perfect Soil
Onions have very shallow root systems. They need loose, fluffy soil to expand properly. If your soil is heavy clay or compacted, your candy onions will stay small and might even rot.
Soil Texture and Drainage
Amend your garden soil with plenty of well-rotted compost. This improves drainage and adds vital nutrients. If you have heavy clay soil, consider growing your candy onions in raised beds or mounded rows. Raised beds warm up faster in the spring and provide the perfect loose environment for onion roots.
Adding Nutrients
Candy onion plants are heavy feeders. Before planting, mix a balanced, slow-release fertilizer into the top few inches of soil. Onions love nitrogen. A fertilizer with a higher first number on the bag, like a 10-10-5, will promote strong top growth, which directly leads to larger bulbs. Properly planting onion bulbs also requires keeping the area weed-free, as onions have shallow roots and struggle to compete with aggressive weeds.
Caring for Your Candy Onion Plants
Once your candy onion plants are in the ground, the real work begins. Keeping them happy and stress-free is the secret to a sweet harvest.
Watering Needs
Onions need about one inch of water per week. If you do not get enough rain, you will need to water them deeply. Inconsistent watering causes onions to become stressed. A stressed onion will either bolt (send up a flower stalk) or split into multiple bulbs. Water in the morning so the leaves have time to dry out during the day. Wet leaves overnight can lead to fungal diseases.
Fertilizing Tips
Feed your candy onions every two to three weeks with a liquid nitrogen fertilizer, like fish emulsion or a diluted all-purpose plant food. Stop fertilizing when the necks of the onions start to feel soft. This is a sign that the bulbs are finished growing and are starting to mature. Continuing to fertilize at this point will just cause the bulbs to rot.
Mulching and Weeding
Apply a layer of organic mulch, like straw or shredded leaves, around your plants. Mulch keeps the soil cool, retains moisture, and blocks out weeds. Because onion roots are so shallow, never hoe deeply around them. Pull weeds by hand to avoid damaging the tiny root system.
Harvesting and Curing Candy Onions
The harvest is the most exciting part! But you must be patient. Harvesting too early will result in onions that do not store well.
Signs They Are Ready
Your candy onion plants are ready to harvest when the green tops start to fall over and turn brown. This usually happens in late summer. When about half of the tops have fallen over, bend the rest over to the ground. This forces the plant to stop growing and start maturing the bulb.
The Curing Process
After a few days, pull the onions out of the ground. Do not wash them. Brush off the excess dirt with your hands. Curing is the process of drying the outer skin and neck of the onion. Lay your onions out in a single layer in a warm, dry, and airy spot out of direct sunlight. A covered porch or a garage with open doors works great. Let them cure for two to three weeks until the necks are completely tight and dry. Once cured, trim the roots and cut the tops off about one inch above the bulb.
Common Pests and Problems
Even the best gardeners run into trouble. Here is how to handle the most common issues with candy onion plants.
Thrips and Onion Maggots
Thrips are tiny insects that suck the sap out of the leaves, leaving silver streaks. You can get rid of them by spraying the plants with insecticidal soap. Onion maggots lay eggs at the base of the plant, and the larvae eat the roots. Using row covers over young plants is the best way to prevent maggots from reaching your crop.
Rot and Disease
Bulb rot is usually caused by overwatering or poorly draining soil. If you notice a bulb turning to mush, pull it immediately to prevent the rot from spreading to other plants. Downy mildew is a fungal disease that causes fuzzy patches on the leaves. Ensure good air circulation by properly spacing your plants to keep mildew at bay.
Growing candy onion plants is a fun and rewarding gardening project. By starting with good soil, providing consistent water, and curing your harvest properly, you will be rewarded with the sweetest onions you have ever tasted. There is nothing quite like the satisfaction of pulling a massive, mild onion from your own garden. Happy planting!
Frequently Asked Questions
How long does it take to grow candy onions?
Candy onion plants typically take between 90 and 100 days to reach full maturity from the time you plant transplants or sets. If you start them from seed, expect the process to take closer to 120 days.
Can you grow candy onions in containers?
Yes, you can grow candy onion plants in containers! Choose a pot that is at least 10 inches deep and 8 inches wide to give the bulb enough room to expand. Ensure the container has excellent drainage holes.
Are candy onions long-day or short-day onions?
Candy onions are day-neutral. This means they are not dependent on specific day lengths to form bulbs, making them incredibly adaptable to almost any growing zone in the country.
Why are my candy onions not bulbing?
If your plants are growing tall green tops but not forming bulbs, they might be getting too much nitrogen or too much water. Additionally, if the soil is too compacted, the bulb cannot push the dirt aside to expand properly.
Do candy onion plants flower?
While it is possible for any onion to flower, candy onions are usually harvested before this happens. If the plant experiences a sudden temperature shift, it might bolt and send up a flower stalk. You should pinch off the flower stalk immediately to redirect energy back to the bulb.
How do you store candy onions after harvest?
After properly curing your candy onions, store them in a cool, dry, and well-ventilated place. A mesh bag or a crate in a basement or pantry works perfectly. Avoid storing them in plastic bags, as they need airflow to stay fresh.