How to Grow Onions on a Balcony

by balconyboss
onions on balcony

Onions are a delicious aromatic vegetable that make the perfect companion to soups, roasts, stir-fries, and so much in between. If you want to grow your own onions and you have balcony space, then consider the following guide that will teach you how to grow onions on a balcony.

Before Getting Started

The following is some essential information you need to know before growing onions on your balcony.

  • Climate: Onions are very hardy when it comes to temperatures. However, they require temperatures between 55 and 75 degrees in order to develop healthy roots, leaves and bulbs. As soon as an onion has “bulbed,” it can tolerate temperatures that are higher than 75 degrees. If you aren’t able to keep the onions cooler while they ‘bulb,’ then you may want to consider a different plant. Onions should be planted once soil can be tilled in the springtime.
  • Sunlight: Onions need 13 to 16 hours of sunlight per day while they are forming their bulbs. The more sunlight the onions get, the larger they will grow.
  • Planter: Onion containers should be at least 6 inches deep and 6 inches wide. The larger the container, the more onions you can grow in them.
  • Indoors or Outdoors? Onions can grow indoors, but you will need lots of space and access to a spot indoors where the plants will be able to get full sunlight for many hours per day. They will likely be easier to grow outdoors and you are more likely to get a better harvest with full outdoor sun.

What You’ll Need

The following are some basic supplies you’ll need to grow onions on a balcony.

  • Onion seeds
  • Soil
  • Container
  • Fertilizer

Step by Step Instructions

The following step by step instructions will get you started when growing your onions on a balcony.

1. Prepare your container

First, prepare your container with some high quality potting soil. Make sure that the soil is about 60 degrees before you plant, or else your onions will be too cold to start growing.

2. Plant your onions

Plant your onions in your container about 3 inches deep into the soil. If you plant more than one at a time, make sure they’re at least 1-2 inches apart. Cover them with soil, gently, and water.

3. Maintain your plants

The initial 3-4 months after planting is crucial for your onion plants, as this is when the roots and bulbs develop. Take extra care to look for pests and signs of issues like rot or root disease, as these could ruin your harvest.

Growing Notes

  • Water: Onions need about an inch of water throughout the week, so you should water them at least once a week with 1-inch of water or in smaller spurts throughout the week until you get to a 1″ total. Onions are VERY vulnerable to water-based disease and rot, so never over water your onions.
  • Growth: It will take about 100 to 175 days for your onions to go from planted to mature enough to harvest. For this reason, some people begin them indoors in a very sunny area so that they can enjoy them earlier in the season.
  • Maintenance: Onions absolutely need a nitrogen-based fertilizer if you want them to thrive. Fertilizer should be first applied about 3 weeks after the initial planting, and then applied every 3 weeks after that.