What to do with onion flowers

What to do with onion flowers. Onion (Allium cepa), a biennial plant, is classified in Liliaceae and is grown for the edible bulbs that reach their full size in three to four months (100-120 days) from planting.

What to do with onion flowers
What to do with onion flowers

If the onions bolt, snip the flowers off the top and prevent the onion bulbs from getting wasted.

Onion Development Stages

Onions are biennial plants and possess two developmental stages.

One year is required for the growth, while the flowers and seeds production starts in the second year. 

Maturity Season

They mature in the early to mid-summer.


The matured onion plant reaches 6 inches (15 cm.) in length. 

The height indicates a sign that your onions are ready for a harvest, and the longer you wait for the green tops, the bulkier the bulbs obtained. 


Bolting is the blooming of flowers before the desired period. 

Onions are prone to bolting and produce blossoms at the wrong period.  In bolting, the blossoms emerge in the first year. 

You might be thinking you have wasted all the energy and time by planting onions, but you can still harvest the crop.  Remember, the vegetables might be of smaller size.

What to Do With Onion Flowers Onions after Bolting?

You might be thinking about what to do with these early-grown onion flowers, don’t worry! 

Let’s get to know what can be the remedy to this problem.


When the onions bolt, don’t leave the flowers as such. 

  • Snip them off the flowers at the top of the onion plant. 
  • You can snip the blossoms 1 inch (2.5cm) above the onion bulb. 
  • By leaving the bolted plant as such, you may waste your time and plant energy in making seeds that are of no concern in bolting. 
  • The bulbs may even start to rot if the foliages are without snipping. 
  •  It’s better to harvest as they won’t grow in size.
  • If you observe a mix of bolted and unbolted plants, go for the bolted ones first. 
  • Snipping them will avoid any further harm to the onion bulb. 
  • Let the unbolted ones mature to gain a better harvest later.

Causes of Bolting In Onions

Onions and other members of the allium family are more prone to bolting. This family has the characteristic to produce flowers once every two years. 

When the plant bolts, they produce flowers in the first year.

Low Temperature

Low Temperature

A low-temperature range (10-120C) may cause bolting in the onions. 

Over Age Seedlings

A seedling more than ten weeks older is susceptible to bolting because such seedlings may find it hard to start growth.  

If there is a nutrient deficiency in the soil, the plant is more prone to bolting.

Factors that induce bolting

Bolting in onions is induced by one of the following factors:

Temperature, cultivar, availability of nutrients, time of planting, age of seedlings at the time of transplanting, poor quality seed, during the seedling stage in a nursery bed, and during growth in the field, etc.

Avoid Onions Bolting

Heat Treated Onions

Go for hardy heat-treated onion sets to avoid bolting. They include:

  • Rumba
  • New Fen Globe
  • Fen Early
  • Red Fen
  • Red Ray

Bolt Resistant Varieties

The varieties of onions available with good resistance to bolting include

Storage of Bolted Onion Bulbs

Store the bolted onion bulbs for seven days. Utilize them within this time frame. If they are excess, chop them and freeze them for later use.


Onion (Allium cepa), a biennial plant, is classified in Liliaceae. If the onions bolt, snip the flowers off the top and prevent the onion bulbs from getting wasted.

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