The door creaks open unleashing a wave of intoxicating aromas; sweet, spicy, pungent…onions.
I know that there is something incredible about to envelop my entire being with mouth-watering flavor when I walk into a room heavy with the scent of onions cooking. They are a bulb rooted to the heart of every kitchen in the world. Whether high class fine dining on linen or mud ovens and cast iron, onions will transform a paltry set of ingredients into a savory waltz of gustatory delight.
Onions are a guest of honor in most gardens across the country. Not only do they taste incredible, they also repel some unwelcome pests from tender vegetables, benefit the growth of brassicas such as kale, cabbage, broccoli, and collards, and do well as a container crop.
The possibilities with container gardening are one of the most exciting things for me. When I am walking around town looking at the tiny yards, apartments, balconies, and porches I see the potential for incredible gardens. Onions are a great addition to these little oasis’s and require less space than one would imagine.
Step One: Picking out the container.
Onions require only around 3 – 6in. of space between sets and a minimum of 10in. of soil depth. Your containers can be anything from plastic buckets to small raised beds. I’ve seen onions growing in old rustic wheelbarrows, window boxes, and tin buckets. Choose something with good depth that you enjoy and you will be good to go.
Step Two: Soil and Fertility
Onions are delighted by a well composted soil with neutral ph. You will want to have a good balance of the three essentials; Nitrogen, Phosphorus, and Potassium. If you need to address fertility issues stick to a low nitrogen organic amendment ensuring you feed your bulbs with a good dose of phosphorus as well. There is a lot of conflicting information out there about how much nutrient to give your onions. A good rule for underground bulbs and tubers is that the more nitrogen you give them the more top growth you will get. This excess of growth inhibits root formation resulting in smaller bulbs. Phosphorus helps to establish healthy root formation and a better yield from underground crops.
A note on soil type: Some gardeners and farmers say that you must have fluffy loamy soil for good onion production. Unless you are looking to grow designer onions which could be sold on the shelves of Crate and Barrel don’t let that intimidate you. In general you will want to fill your container with soil mostly free from rocks that has a balanced consistency; not to much clay and not a sand box.
Step Three: Planting and Watering
Plant onion sets outside in containers about four weeks before the last frost date for your area. If
If there is still a danger of a serious freeze move your containers to a protected area and cover them with a cold frame, plastic sheeting, or other protective material. Onions are thirsty crops and require monitoring to ensure they do not become dehydrated or waterlogged. On windy or hot days check on your onions more often than you would during and average day.
Step Four: Harvest and Eat
Depending on the variety of onion you grow, at harvest time you may need to have a curing period for long term storage. It is best to cure your onions outside for a full day after harvest if the weather is warm and sunny. After the initial drying you can bundle them together and hang them in a cool dry place for later use. You’ll want to make sure there is plenty of airflow as it helps avoid problems with mold or mildew. If you have grown fresh eating onions it will be better to leave them in the ground as the temperatures cool; mimicking a natural refrigerator, then eating them as you like.
For more information on the best onions to grow for your region check out our post: Onions: Short Day vs Long Day