Alliums can be grown in pots although they will definitely grow better if planted directly into the garden. Potted Alliums will grow just as large as the ones planted in the garden, provided that the potting mix is high quality and you keep up with the watering. A big pro of potted Alliums is that you can easily relocate the pots to a new area, and fill a corner of your garden or balcony with different types of Alliums.
Alliums are best planted in the fall, typically between September and November, before the soil freezes. These plants are relatively low maintenance and prefer dry conditions, so watering is rarely necessary. Select a sunny location for planting, water them upon planting, and then simply wait for the beautiful blooms to appear in late spring or early summer.
You can even plant different types of Alliums in the same pot as most Allium varieties have the same needs. Just keep in mind that different types of Alliums will flower at different times, so you should either plan for one massive bloom or make the blooms staggered which gives you flowers for a longer period of time. Make sure to use a larger pot if you want to plant different types of Alliums together.
Alliums tend to have relatively shallow roots, a wider pot is recommended, especially if you plan to keep them in the same pot for several years. When you plant the Allium bulbs in pots make sure to plant them 3x times deeper than their height and in such a way that the bulbs do not come in direct contact with the pot as this can damage the bulbs in the long run. For more information about planting Alliums in the spring check out my recent article Planting Allium Bulbs In Spring ( Good Idea? ).
When To Plant Allium Bulbs In Pots
Allium bulbs can be planted in pots in the fall, ideally around 4 to 6 weeks before the first frost date in your area. This timing allows the bulbs to establish their roots before winter sets in. Choose a pot with good drainage and fill it with well-draining potting soil. Place the bulbs about 2 to 3 times their own depth into the soil, with the pointed end facing up. Space the bulbs a few inches apart to allow for proper growth. After planting, water the pots thoroughly and place them in a cool location where they will receive indirect sunlight.
During the winter months, the pots can be moved to a protected area or covered with mulch to insulate the bulbs. In spring, as the weather warms up and the bulbs start to sprout, you can gradually move the pots to a location with more sunlight. Regularly water the pots throughout the growing season and enjoy the beautiful blooms of your potted alliums.
In Autumn
The ideal time for planting Alliums in pots or into the garden is during the autumn, mostly because these bulbs do need some exposure to cold. Alliums planted in the autumn will be stronger and healthier than the ones planted in the spring, although the ones planted in the spring will still flower in the first year with some luck. If you will keep the potted Alliums outdoors during the winter then plant them in the autumn.
This way the Alliums will benefit from the cold exposure and due to the increased moisture, they will not dry out. One of the most common problems with Alliums is that they tend to get bulb rot, but planting them in pots reduces this risk significantly, just make sure that the potting mix is a well-draining one. If you are planning to keep the potted Alliums indoors during the winter, then you might as well not plant them until the spring.
Alliums will go dormant once the temperatures drop for a couple of weeks at least, if you keep them indoors they will not go dormant and the bulbs will sprout. Although you can grow Alliums indoors as well, but the low light conditions during the wintertime will make them grow weak and leggy. If your Alliums are starting to fall over then check out my recent article Why Are My Alliums Falling Over? ( Top 6 Reasons ).
In The Spring
Planting Alliums in pots during the spring is not ideal, but it is definitely better than planting them in pots during the autumn and keeping them indoors where they will not be able to go dormant. If you are worried that your Alliums will not survive the winter, and this is the main reason why you plant them during the spring, then you should check the Hardiness Zone of your Alliums, most of them will survive even relatively cold winter.
Ideally, you should grow the potted Alliums outdoors under full sun, although they will grow indoors as well, provided that you place them next to a well-lit window, but they will be significantly smaller if grown indoors. Alliums can be easily grown from seed, especially in pots, for more information check out my recent article How To Grow Alliums From Seed ( In 7 Easy Steps ).
Key Takeaways
- Potted Alliums should be planted in the autumn, and ideally left outside. This way the bulbs can benefit from being exposed to the cold which makes the bulbs go dormant. You can also plant potted Alliums during the spring, but the plants will be smaller, and they might not flower in the first year. If you want to plant your Alliums during the autumn in pots, and then keep them indoors, then my advice is to simply pot them in the spring or pot them in the autumn and leave them outside.
- Ideally, you should plant your Allium bulbs in pots in autumn and then simply leave the pots outside.
- If you want to grow your Alliums indoors then plant them during the spring as the indoor light levels during autumn and winter are way too low for them to grow well.
