Onions

What with weather conditions (not just now but since you planted) and the potential variability of any given area, we can't say exactly. Watch for the tops to become yellow and begin to fall over. Stomp (per our advice on this page) and pull the onions when the tops are brown.
Here in New Hampshire, that's usually in late summer.

Months. If you plant in the fall to let the bulbs overwinter in the ground, they would mature near the end of summer, when the green tops dry and flop over. If you plant in the spring, you have to look for the same signs before harvesting.

Onion bulbs are mature when the foliage--the green tops--dry, turn brown and fall over. It's usually late in summer.

This is a cattail! not a green onion, You can eat the roots.

You will not get an edible onion out of this, but you will get onion seeds (and green onion cuttings, I suppose).

It sounds like you have onion maggots. The adult onion maggot fly lays it's eggs in the soil around onion plants in the spring and the maggots appear when the soil warms up. Yellow sticky traps will capture the flies in the early spring or you can use row covers to protect the onions. Plant a new row of onions in a different spot of your garden. Try red onions which are more resistant.

Garden lore tells us that bending the green leaves of onions close to maturity will help the plant to spend more energy on bulb growth. Unfortunately, this is not the case. The plant needs the leaves in working order so that they can make food for bulb growth. Bending or otherwise damaging the green leaves (such as via storm damage) will harm the growth of the bulb.

Because of hail damage, it is possible that your bulbs will be smaller this year. Harvest time might actually be delayed, depending on the percentage of leaves lost on each plant and the ability of the plant to recover. Some leaves might heal and help with bulb growth, or new leaves start to form, so we'd recommend leaving the plants alone in case they will perk up again. Wait until the leaves have yellowed and browned on their own before harvesting the bulbs.

Flowers on onions are not desirable (unless saving seed), as it compromises the quality of the bulb. Flowers can be triggered by temperature fluctuations (such as a period of warmth, followed by cold, followed by warmth).

A bulb uses energy to send up a flower stalk (called bolting), so once it does, the bulb will be smaller and won't be as large as an onion that does not bolt. It is still edible, but lower in quality. It is not necessary to cut off the flower stalks (some gardeners do, some don't), but you should harvest the bulb as soon as you can, and use it promptly--it will not store well.

When buying onion sets, look for those that are no thicker than a pencil, and plant them out at a time recommended for your area; larger sets tend to bolt. Also, keep in mind that 1015 onions are a short-day variety; make sure that type is recommended for your area. Short-day varieties form bulbs when daylength is between 10 and 12 hours; intermediate-day (day-neutral) onions start to form bulbs between about 12 and 14 hours of daylight; and long-day varieties form bulbs at about 14 to 16 hours daylight. If a short-day variety is planted in an area best suited for a long-day type, for example, then the bulbs might form early and not get very large. A general rule of thumb for the U.S. is that northern gardeners use a long-day type, gardeners in the mid-section use day-neutral, and southern gardeners, a short-day type.

Onions come in long-daylength, medium-daylength, and short-daylength varieties, based on amount of sunlight needed. You grow long-daylength in northern latitudes and medium-daylength in central latitudes. In the southern latitudes, you need to plant short-day onions. Short-day do not come in sets. You need to seed OR plant bareroot transplants from local nurseries.

For home garden use, either usually type usually meets the plant's requirements. Leafy veggies usually do better with a complete balance, and tuber/root veggies as well as flowers usually do better with 6:12:12.

Fertilizing onions is critical to success. Before planting, work 4 to 6 inches of well-composted organic matter and an all-purpose fertilizer (16-16-8) into the soil to a depth of 6-8 inches. Then, 4 to 6 weeks later, sidedress onions with nitrogen fertilizer (21-0-0) as directed. Do not
fertilize after mid-July as extra nutrients stimulate late season growth and reduce storage potential of dry onions.

Store sets (the tiny immature bulbs) in a cool, dry, dark environment if planting must be delayed after purchase.

Onions are considered a belowground crop. Plant during the dark, or waning, of the Moon: from the day after it is full to the day before it is new again.

Georgia Sweet onions are planted 6 inches apart in rows 12 inches apart for full sized bulbs.