Alliums can thrive in either full or partial shade, however full sun is preferred.
The bulbs are typically winter-hardy in hardiness zones 3–8. See this USDA Hardiness Zone Map to determine your growing zone.
Alliums require well-drained soil that does not become wet in order to be cultivated, just like the majority of other bulbs.
Where to Plant Alliums
Most alliums bloom in late spring, right after the last tulips and before irises and peonies, in perennial gardens. The flowers last for weeks and give the garden a balloon-like appearance as they float above it. After flowering, the foliage and flowers disappear, making space for summer perennials to take the lead. Allium christophii, Gladiator, Globemaster, Purple Sensation, and more excellent alliums for perennial gardens include these.
Alliums do well in rock gardens, where they flourish in the well-drained crevices between the boulders. Select species with smaller leaves, such as Allium sikkimense, Allium flavum, and Allium karataviense.
Alliums make great cut flowers, according to cutting gardens. The flowers remain a very long time and are easy to arrange thanks to their rigid stalks. You may guarantee that you’ll always have an abundant supply of flowers for bouquets by planting alliums in a cutting garden. You’ll receive flowers all season long if you select a variety. Purple Sensation, Allium atropurpureum, Mount Everest, Allium sphaerocephalon, and Allium tuberosum are all good choices.
Containers: Whether grown alone or in combination with other plants, many alliums thrive in containers. When the flowers blossom, you can relocate the planter to a visible location so that you can enjoy the flowers.
How to Plant Alliums
When to Plant: Bulbs-based alliums are planted in the fall, just after the first frost and before the ground freezes. Like other perennials, herbaceous alliums (such as Allium tuberosum and Allium millenium) have fibrous roots. You can plant these at any point of the growing season.
Planting Depth and Spacing: Planting depth is based on bulb size. Smaller bulbs, such drumstick alliums, should only be planted 3 deep in comparison to larger bulbs like Globemaster, which should be planted 5 to 6 deep. Follow the plant-specific directions on the packaging or on our website for the best results.
Planting advice: You don’t have to be concerned about deer, squirrels, or voles when growing alliums. Allium bulbs have an onion-like flavor that repulses them, and they almost invariably leave them alone.
Do alliums withstand frost?
- 5F (15C): some leeks (Bulgarian Giant, Laura, Tadorna, Bandit), garlic tops if still little, some bulb onions, potato onions, and other multiplier onions.
- 0F (18C): Walla Walla onions sowed in the late summer; chives, garlic, a few leeks (Alaska, Durabel); some bulb onions, yellow potatoes, and onion scallions (Evergreen Hardy White, White Lisbon) (with rowcover for winter)
Plant when the soil is 50F (10C) at 9 am when it is 4 (10 cm) deep. Wait a week if the fall is extremely warm. Texas A&M’s guidelines state less than 85F (29C) at 2 (5 cm) deep. In early November, we plant. Mid-October is the time of year in New Hampshire. For regions with chilly winters, the recommendation is two to three weeks after the first frost but before the ground completely freezes over for the season. In order to prevent freezing of the foliage, Michigan plants should be planted six weeks before the ground freezes. Garlic can be planted in California in January or February.
Although softneck garlic can also be planted in the very early spring if necessary, both hardneck and softneck garlic grow best when planted in the fall (with reduced yields). If you miss the window for planting in the fall, make sure your seed garlic spends 40 days in storage at or below 40F (4.5C), otherwise the lack of vernalization will prevent the bulbs from differentiating (divide into separate cloves).
When the ground is not frozen, garlic roots will develop, and when the temperature is above 40°F, garlic tops will grow (4.5C). The objective in colder climates is to get the garlic to start rooting before the big freeze, but to delay starting top growth until after the worst of the weather. In warmer climates, the objective is to have enough top growth in the fall to get things going in a big way in the spring, but not enough top growth to prevent the leaves from surviving the winter. Garlic may grow again and be fine if it freezes to the ground throughout the winter. The yield will be lesser than it may have been if you had been more fortunate with the weather if it dies back twice in the winter. It can endure winter lows of 30F when planted properly (35C). If planted too early, there will be an excess of fragile top growth before winter. Inadequate root development before the winter, a decreased survival rate, and smaller bulbs are all consequences of planting too late.
When you consider that you are planting one clove to receive a bulb of 67 cloves, a yield ratio of 1:6 or 7 looks usual and makes perfect sense. To calculate how much to plant, divide the intended output by six. For planting in double rows, 34 in-row (7.510 cm) and beds 39 (1 m) apart, big areas require 7501,000 lbs/ac (8421,122 kg/ha). For single rows, 100 plants weighing 8 lbs (3.6 kg) of hardneck or 4 lbs (1.8 kg) of softneck (30 m). One individual eats 39 lbs (1.44.2 kg) of food annually in the US.
Seven days before planting, the garlic should be divided into individual cloves. On November 7, when the team gathers to discuss the previous season, we will also be conducting this along with our crop review meeting. This exercise makes for a fun group project. Twist off the outer skins and peel the bulb apart, being careful not to damage the cloves’ basal plate, which is where the roots originate. If you do, you won’t be able to plant them. For separating the cloves in hardneck garlic, the remaining stem serves as a useful lever. We separate the cloves as we go, putting the healthy ones in large buckets, the broken ones in kitchen buckets, the small ones in tiny buckets, and the rejects and outer skins in compost buckets. Scallions made of garlic are seeded from the tiny cloves. The cloves won’t die if some of their skin peels off; they will continue to develop. Planting cloves should be from large (but not enormous) bulbs that are in good condition.
For the most part, we don’t do anything extra before planting the cloves, but if you have pest or disease issues, employ pre-plant soaking treatments, often carried out the night before planting. Even when there was no visible issue, some gardeners discover that treated cloves produce higher yields.
Soak the divided cloves for 30 minutes in 100°F (37.7°C) water containing 0.1 percent surfactant to get rid of the stem and bulb (bloat) nematode (Ditylenchus dipsaci) (soap). Alternately, you might soak for 20 minutes in a solution of the same strength at 120F (48.5C), then cool in plain water for 10 to 20 minutes.
Allow to dry for two hours at 100 F (37.7 C), then plant. Send a sample of the soil your garlic is growing in to your local Extension Service to be tested for nematodes whenever you notice it isn’t growing well and you’re not sure why. Clove mites can chew through the skins, survive the winter, and continue to reproduce throughout the spring, severely harming or even obliterating your crop. Before planting, divide the bulbs into cloves and immerse them in water for up to 16 hours to kill the mites (which lurk between the wrappers).
One heaping tablespoon of baking soda and one tablespoon of liquid seaweed per gallon are potential additions to the water (around 8 ml baking soda and 4 ml liquid seaweed per liter). Drain the cloves and soak them in rubbing alcohol for three to five minutes right before planting. This will allow the alcohol to permeate the clove coverings and kill any mites that may be present. after that plant right away. The clove skins will become more permeable to the alcohol after a prolonged soaking. Garlic that has been infected with mites but has been properly soaked performs significantly better. Various fungi infections can be cured using the same solution that kills mites. The cloves just need to soak for fifteen to thirty minutes.
Trials comparing treated and untreated cloves revealed that treated cloves were bigger and healthier. Fusarium levels can be controlled by planting with wood ashes and then dusting the beds with additional ashes during the winter (use moderation; don’t add too much or the soil will become alkaline). Alternately, you might soak the cloves in a solution of 10% bleach before rolling them in wood ash (wear gloves for handling ashy cloves). The wood ash acts as a potassium supply while absorbing the bleach’s moisture. The Garlic Seed Foundation provided this information. Join GSF to learn all the specifics!
In zone 7, plant medium-sized potato onions (1.52, 4-5 cm) around the end of November or early December and shallot bulbs before the end of November. This month, complete the division and replanting of perennial leeks and Egyptian walking onions.
We created a technique whereby onion seedlings are grown over the winter in our hoophouse before being transplanted bare-root outdoors very early in March. Last month, I wrote about picking the right onion cultivars for your latitude. There, I outlined the requirement for large transplants on March 1 in order to have huge vegetative plants before bulbing is initiated by the length of the days.
Two sowings of bulbing onions, each sufficient for the entire planting, are made using the procedure. This offers protection in the event that one date goes better than the other. Then, to make up for any kinds that didn’t germinate properly, we make a partial third sowing. On November 10, November 20, and December 5 we sow our first, second, and backup crops, respectively. To get the minimum length of the row that must be sown, in feet, divide the desired number of onion plants by 20. 10 days apart, sow this amount twice. The spacing between the onions will be 4 (10 cm). To add some wiggle room, we add 20%. For a final row of 100 (30.5 m), we would require 1003 plants per foot1.2 (plus an additional 20%). 336 plants. We plant 36 seeds per foot at 3 seeds per inch (or 1 centimeter apart) (30 cm). At this rate of seeding, we require 120, or 10 (3 m).
The Year-Round Hoophouse has further information about producing onions in this manner. In March, if we have additional onion plants, we normally reclassify them as scallions. To ensure an early production, we also transplanted them in early March in a single row along the south side of the hoophouse beds. Although we had good onions, the pepper plants behind them were dwarfed by them. Perhaps it would be best to plant them on the north side of the bed?
Last month, I wrote about how to dig leeks. We leave our leeks in the ground in zone 7 until we need them, making sure to collect the King Richard and Lincoln, which are less hardy, first. The root ends are kept in water and are kept in a walk-in chiller for short-term storage (up to a week). At 33F (0.5C) and 65 percent relative humidity, leeks store well. Leeks can be gathered and kept in a root cellar or basement in colder climates. In regions where the ground freezes solid for weeks on end, this is useful. Leeks last for six weeks when packed shoulder to shoulder in a crate or box in a root cellar with the roots submerged in dirt. They can be frozen or kept at the proper temperature for two to three months in plastic bags. If temperatures are below 10F, another option is to leave them in the garden mulched with a foot (30 cm) of straw or hay in addition to rowcover (12C). Because of the wide variations in our winter temperatures, mulching in-ground crops is not effective in our area.
Can allium bulbs be left in the ground over the winter?
Post-bloom maintenance for alliums is quite simple. Simply continue to water the plants sparingly until they start to shrivel and turn yellow. At this point, you have the option of either dividing the plants or cutting them all the way to the ground.
Divide allium bulbs every three to four years. Simply use a shovel to dig around the plant and lift the bulbs out. You should see a group of bulbs that you may gently separate with your hands. Replant a few in the same location, and immediately transplant the others to different sites.
It’s considerably simpler to take care of allium bulbs that you don’t wish to divide. When the foliage starts to fade, simply trim it back, and in the fall, mulch the soil with 2 to 3 inches (5-7.5 cm) of material. In the spring, remove the mulch to allow room for fresh growth.
What environments favor alliums?
Consider your garden space when choose which alliums to cultivate. Will you be bulk-planting in pots or growing in drifts through the border? as a component of a structured planting plan for prairies? Additionally, it’s crucial to consider the color of your alliums. Although most allium blossoms are purple, some are also blue, white, yellow, and pink in color. Also take into account the size of your allium—both the size of the flowers and the plant’s overall height. Allium flowers can range in size from a few centimeters to over 20 cm (8 in) in diameter, and their eights can also differ greatly.
Planting large, tall alliums singly or in drifts works nicely for varieties like “Purple Rain” and “Globemaster.” Allium christophii and other shorter variants grow well in containers. In prairie planting designs, drumstick alliums like Allium sphaerocephalon look fantastic.
Where to plant alliums
Alliums thrive in a sunny location with excellent soil drainage. They don’t care what kind of soil it is. Plant higher-growing cultivars in the back of a border and lower-growing varieties up front. Although alliums do well in containers, their strappy foliage can become ugly after flowering.
The leaves of alliums develop before the flowers do. As a result, they are frequently better suited to the center of a border where the faded foliage would be hidden and the flowers will put on a display. Plant alliums among attractive grasses and perennials to hide the fading foliage.
Grow alliums in broad drifts through the border or let them naturally grow in your lawn for a striking show.
How to plant alliums
Plant allium bulbs in the fall, at least four times their size deep (at least 15cm deep). It is preferable to plant them deeply rather than superficially.
There is no need to water them in if the soil is damp. Poor soils should be fertilized with a balanced fertilizer in the spring as growth begins to show.