The “Candy Onion” is a specific hybrid variety of Allium cepa celebrated by home gardeners for its reliability and rapid maturity, often taking only 90 to 100 days from transplanting to harvest. This cultivar offers a highly desirable flavor profile, combining substantial sweetness with very low pungency. Unlike many sweet onions, the Candy Hybrid also offers a reasonable storage potential of up to three months when properly cured. The variety is designated as an intermediate-day or day-neutral type, meaning it is widely adaptable and can be grown successfully across a large range of latitudes.
Selecting the Site and Timing the Planting
Selecting a site that receives full, direct sunlight throughout the day is necessary, as onions are a leaf crop requiring maximum light exposure to produce large bulbs. The soil structure is important; onions possess shallow root systems that require loose, well-drained soil, ideally a sandy loam, to prevent waterlogging and allow for proper bulb expansion. Heavy clay soils should be amended with organic matter to improve aeration and drainage before planting.
Soil preparation should also include a test to confirm the pH is within the preferred slightly acidic range of 6.0 to 6.8. Because the Candy Onion is an intermediate-day variety, it requires approximately 12 to 14 hours of daylight to trigger the bulbing process. Gardeners typically plant these onions four to six weeks before the last expected spring frost, giving the young plants a substantial vegetative growth period before the summer solstice triggers bulb formation.
Planting Methods and Depth
Candy Onions are typically grown from small, dormant bulbs called sets or from small green transplants, as direct seeding is often less successful and slower. Transplants are often preferred because they allow for the selection of specific varieties and generally produce larger, more uniform bulbs than sets. These young plants should be set into the prepared soil just deep enough to cover the roots and the white base of the plant, leaving the neck and green portion fully exposed to the air.
Proper spacing is necessary to allow the bulb to swell to its full potential, which can be up to six inches in diameter for this hybrid. Plants should be spaced about four to six inches apart within the row. Planting too deeply or hilling soil up around the base of the plant inhibits the natural bulbing process, which is signaled by the plant sensing the exposure of its neck to the air.
Essential Care for Growth
Onions are considered “heavy feeders” that require a consistent supply of nutrients and moisture to develop the large, fleshy leaves that directly correlate to the final size of the bulb. Since the root system is shallow, consistent, shallow watering is necessary; the soil should be kept steadily moist, especially as the bulb begins to expand. Watering should be deep enough to soak the top several inches of soil, but cease watering once the tops begin to naturally fall over near harvest time, which aids in the curing process.
The plant has a high nitrogen requirement early in the season to fuel vigorous leaf growth, with a majority of the nitrogen uptake occurring after bulb initiation. Apply a high-nitrogen fertilizer, such as ammonium sulfate (21-0-0), as a side dressing every few weeks after the transplants are established. Applying this fertilizer along the side of the row and scratching it lightly into the soil helps deliver the nutrients directly to the root zone.
Stop all nitrogen applications once the bulb is roughly two-thirds of its expected final size, or when bulbing starts, which is typically around mid-season. Excess nitrogen late in the season encourages the growth of large, thick necks that are difficult to cure and can result in soft bulbs with poor storage quality. Consistent, careful weeding is also paramount because shallow-rooted onions cannot compete against weeds for moisture and nutrients; any deep cultivation must be avoided to prevent root damage.
Harvesting and Post-Harvest Curing
The signal for harvest occurs when the tops of the Candy Onions naturally weaken, bend over, and begin to yellow. This indicates that the plant has stopped its vegetative growth and is redirecting its energy, flavor compounds, and color from the leaves into the bulb. Once approximately two-thirds of the tops have fallen over, the bulbs are ready to be lifted from the soil.
Harvesting involves gently loosening the soil around the bulbs and pulling them up on a clear, dry day, taking care not to bruise the flesh. The most important step for ensuring long-term storage is the curing process, which involves drying the outer skins and the neck of the bulb. Curing should take place in a warm, dry, and well-ventilated area, such as a covered porch or shed, away from direct sunlight, for two to four weeks.
The onions are fully cured when the neck is dry, tight, and shrunken, and the outer skin has a papery, rustling texture. Once cured, the roots can be clipped close to the bulb, and the dried tops trimmed to about one or two inches above the neck. This process seals the bulb, preventing the entry of moisture and microorganisms, which prepares the Candy Onions for their typical storage life of up to three months.