Onions (Allium cepa) are cold season crop that is best to plant in the early spring from October through December in the fall season. Depending on the season, onions yield better if you even plant them in September. You will also get the larger ones because they take time to mature, about 14 weeks or about 4 months which will sprout in the winter.

So, is it too late to plant onions? The answer is, no. And the onions yield at the perfect time when winter commences gradually. Even if you plant now or then, yet you will also get a medium size harvest.

Is It too Late to Plant Onions?

If you think it is too late (like dahlias) to plant onions to get the best harvest, the answer will be no; still, you can plant the onions in another season, like spring or summer. But the yield will be less desirable than the perfect time.

If you live in mild winter weather, you can plant in the spring, where onions will grow and form into a bulb phase in the winter. Forasmuch onions harvest is favorable in the cold temperature in the early stage of their growth.

Another significant factor in onion harvest is the length of the day. Since onion is a photoperiodic plant, you have to choose the right time of the long day length to form the bulbs properly, and also, you will get a good harvest.

From that perspective, in late April, when the days lengthen, the onion plant begins to change its form developing its leaves and roots with the process of forming bulbs (not curling like curry leaves). So, you can even plant onions that will be a better time for a good harvest.

Onions cultivated effectively in northern states, with their longer daylight hours, vary from onions grown in the south. So there is a significant difference in the region to plant the onions.

Best Time to Plant Onions

You can plant onions throughout the year, in all regions, and in all seasons, but the bulb’s size and the harvest may vary slightly. The best time will be in the early spring from October through December in the fall season, or you can even plant them in September.

Onion is the most necessary vegetable which is needed in everyday life cooking any items. So, it is being planted all season, but the harvest and bulb size are not the same.

Most seed packets and catalog descriptions indicate which varieties are intended for short-day regions for those onions varieties that begin to form bulbs when the day is only 10 to 12 hours.

Intermediate-day regions are 12 to 14 hours and the long-day regions are for those onions that start to form bulbs when the day is longer than 14 hours or about 14 to 16 hours.

A few onions are term as day-neutral; this variety begins to set bulbs after a particular number of growth days, whereas in any region, you may cultivate these types of onions.

You can even select the optimal varieties based on the region that will best fit you. Long-day onion types are Ring Master, Red Zeppelin, Walla Walla, and Yellow Sweet Spanish.

Some short-day onions are Granex, Southern Belle, and White Bermuda. Intermediate day or neutral onion varieties are Cabernet, Early Yellow Globe, Red Amposta, and Superstar.

Best Time of Optimal Climate for Planting Onions

Based on the optimal climate for planting onions, some consideration varies with the varieties of onions.

Polar Climate

Onions yield the best harvest in the cold season. It makes no difference if the weather is cold and snowing outside when you sow the onions seeds.

They’ll stay dormant until the time comes for them to sprout. But extreme cold weather is not appropriate for the proper formation of the bulb.

Dry Climate for Onion Planting

Onions need constant moisture to develop the bulbs. If the weather is too dry, the bulbs will most probably split for the lack of wetness.

For this reason, the general rule of thumb is to water more frequently to give them proper moisture to develop but ensure that you don’t overwater them.

Temperate Climate

The regions that don’t experience extreme heat or cold are the best growing conditions for onions. You will get the proper season for cultivating the onions in this region.

Moderate weather will help to sprout and form the bulb properly.

Onion Planting in Tropical Climate

The rainfall and soil moisture level might make growing onions in the tropical complexities. Planting onions in a hot, humid area may cause them to rot in the ground, so choose well-draining soil.

Planting on raised beds or rows with healthy, well-draining soil is ideal.

Continental Climate

Planting onion seeds a month or two before the final frost date will increase your chances of success in the harvest. Then, as soon as the soil is suitable, grow them in your garden.

Cold weather is better for the production of onions, and warm weather is favorable to the development of the bulb.

FAQs on Onion Planting Time

Q1. When is the best time of year to grow onions?

Ans: If you wait longer in the spring to plant onions, your onion will be smaller when they start bulbing, resulting in smaller onions. You can wait, but the plants won’t be able to develop before bulbing.

Q2. How late can I plant onions?

Ans: You can plant onions nearly any time of year, but the harvest may vary a bit from the perspective of proper time. So, don’t worry about when to plant onions anymore.

Q3. Which month yields the best harvest of the onions?

Ans: September and early spring, from October through December, is the best harvest of the onions.

Q4. Can onions be planted in late summer?

Ans: For the mid-summer crop, you may plant in the fall. Planting in the spring is better for a late fall or early winter yield.

Q5. Can I grow onions over winter?

Ans: Since onions are a cold-season crop and can sustain temperatures below freezing, you can grow onions over winter & store too, but the bulb’s development remains slow.

Q6. How long do onions take to grow?

Ans: Onions need about 14 weeks or about four months, about 80 to 120 days, for the proper development of sprout and bulb.

In Essence

If you think it is too late to plant onions, you are wrong, and you don’t have to worry about the time of growing onions. Onions are the most necessary plant used in cooking food to get every variety for each region of any climate condition.

If you plant onions in September and early spring from October through December in the fall season, you will get the larger bulb’s onion because this is the proper time to get a bigger and better harvest than others.