Ornamental alliums grow in pots when the container is deep, drains, and sits in full sun. Mix extra grit into bagged potting mix, empty the saucer after you water, and keep the pot cold through winter — not a heated room.
A deep drained pot in full sun
| Factor | Recommended | Avoid |
|---|---|---|
| Size | At least 12 inches deep and wide; 16–18 inches for a large globe | A 6-inch souvenir pot or a hanging basket |
| Mix | Bagged potting mix plus about one-third grit | Garden soil packed into a sealed pot |
| Type | Compact or mid-height ornamental bulbs; clumpers at nursery depth | A four-foot globe in a light plastic tub |
Ornamental onions belong in a patio tub when the pot drains and sits in sun — they are not a windowsill houseplant. [1]
Set the empty pot in full sun before you fill it, because a planted tub is heavy when wet and you will not want to drag it later.
Can you grow alliums in pots?
Yes, in a deep drained container in full sun. Compact and mid-height types are the easier patio plants.
How big should the pot be?
At least 12 inches deep and wide for one mid-height bulb. A large globe wants about 16–18 inches across, and weight.
How to pot an ornamental allium
- Choose a pot at least 12 inches deep and wide, with a drainage hole. Large globes want 16–18 inches.
- Cover the hole with mesh so mix does not wash out. Do not fill the bottom with gravel.
- Fill with bagged potting mix plus about one-third horticultural grit. Do not pack garden soil. [2]
- Plant fall bulbs at the same depth as in the ground — about three times the bulb’s height, pointy end up. If a giant bulb cannot sit that deep, leave at least an inch and a half of mix under it.
- Space bulbs so they do not touch. [3]
- Water once until water leaves the hole. Empty the saucer after 20 minutes.
- Set the pot in full sun. Check the mix every few days in heat.
One mid-height bulb fills a 12-inch pot, and several small drumstick bulbs can share a wider tub if air still moves between them. Clumpers such as Millenium go in at the same depth as the nursery pot, not as deep as a fall globe.
Compact types vs tall globes
Mid-height globes and small species are the easier patio plants. Purple Sensation sits in a deep 12-inch pot without tipping, and Drumstick allium is the small-headed type that fills a wide tub without needing a barrel.
Which allium for a patio pot?
Start with a mid-height globe or a small species. Tall Globemaster-class clumps need a heavy, wide tub, or they belong in the ground.
Star of Persia and Lily Leek still want sun and grit; they just do not need a barrel-sized tub. Ivory Queen is a low clumper that fits a wide pot only if the pot is still deep enough for the roots.
Globemaster and Gladiator reach three to four feet. They can flower in a pot if the tub is heavy and wide, but wind catches the stems and a light pot tips. If you cannot offer width and weight, plant them in the ground.
Millenium is a summer clump, not a fall globe. Pot it at nursery depth and keep the mix from staying wet at the crown. A kitchen chive pot is for snipping leaves, not a stand-in for a May globe — match the habit on Types of Alliums before you buy from a bag photo.
Water, winter, and the saucer
Water when the top inch of mix is dry. Soak until water leaves the hole, then empty the saucer. Pots in full sun dry faster than beds, and they also rot faster if the tray never empties. Feel two inches down before you flood a plant that wilted at noon — heat wilt on a drained pot is not always a cue to water again.
Feed lightly once in spring if at all. A weekly soluble feed makes soft leaves in a pot the same as in a bed.
The pot walls freeze on all sides, and winter rain sits in a saucer. Before hard freezes, move the container to a sheltered wall or an unheated garage. Wrap the pot, not the plant, if it must stay outside. Water enough in storage that the mix does not turn to dust. Do not keep it in a heated room — ornamental alliums need a cold rest to bloom. [4]
How often do I water a potted allium?
When the top inch of mix is dry. Soak, then empty the saucer. Heat and wind on a patio may mean twice a week in spring growth.
Will they survive winter in a pot?
Better if you move the pot to an unheated garage or a sheltered wall, keep the mix barely moist, and leave the leaves until they brown.
After the globes fade, leave the leaves until they brown so the bulb can recharge. You can slide the pot behind other containers while the foliage looks messy.
Grow, plant, or choose a type
Once the pot drains and sits in sun, How to Grow Alliums still covers sun and drainage if you are also planting in a bed. Moving a clump into the ground later is Planting Alliums — fall depth and offsets. Match compact versus tall on Types of Alliums before you buy another bag. Neighbors for a nearby bed are on Allium Companion Plants. In this tub, grow one globe per pot, or only add plants that also like a mix that dries, because a thirsty annual will force extra water on the bulbs.
Size a deep drained pot, mix in grit, empty the saucer, and keep the container cold through winter.
FAQ
Can I use garden soil in the pot?
No. It packs, stays wet, and brings weeds. Use bagged potting mix plus grit.
How many bulbs in one 12-inch pot?
One mid-height globe. Several small drumstick bulbs can share a wider tub if they do not touch.
Do terracotta pots work?
Yes. They dry faster, which helps in a wet winter. You will water more often in heat.
Do I fertilize potted alliums every month?
No. Light feed once in spring is enough. Heavy nitrogen makes soft leaves.
Can I keep an allium as a houseplant in winter?
No. It needs a cold rest to bloom. Use an unheated garage or a sheltered outdoor corner, not a warm windowsill.
Is a chive pot the same as a Globemaster pot?
No. Chives are a kitchen harvest plant. Globemaster is a tall spring globe that needs a deep, heavy tub or the ground.
Do hanging baskets work?
No. They dry too fast and are too shallow for the bulbs.
Should I plant a nursery pot into the bed?
Yes if you bought a garden-center plant to go in the ground — that is Planting Alliums, not this patio method.
When do I move up a pot size?
When the mix is a solid root mass, usually after a season or two. One size up, or plant into the ground.
Can I mix alliums with thirsty annuals in the same tub?
No. Those partners force extra water. Match sun and drain, or grow one plant per pot.
Related guides
Recommended plants
References
- [1] NC State Extension Plant Toolbox -
https://plants.ces.ncsu.edu/plants/allium-cristophii/ - [2] Royal Horticultural Society -
https://www.rhs.org.uk/plants/allium/growing-guide - [3] Epic Gardening -
https://www.epicgardening.com/container-allium/ - [4] Sarah Raven -
https://www.sarahraven.com/blogs/growing-guides/how-to-plant-and-grow-alliums
This note is part of Allium Guides.
More container notes by plant live in Container Growing Guides.
Updated: Reviewed by Bosquelle Editors