By: Bonnie L. Grant, Certified Urban Agriculturist
The climbing onion plant is not related to onions or other alliums, but is more closely aligned with lilies. It is not an edible plant and can be described as an interesting, but not as pretty, specimen of flora. Bowiea sea onion is another name for the plant, which is a succulent without any leaves. The plant grows from a bulb which is often outside of the soil. Growing climbing onion as a houseplant will amaze visitors and give all who see it something to ponder.
Bowiea is the genus for the climbing onion plant. These plants are native to Africa and indigenous where soil is poor, moisture is minimal and heat is severe. They grow well in most home interiors provided there is not excessive humidity. The plant itself is a curiosity, with its surface growing bulb and green starry flowers.
Climbing sea onions (Bowiea volubilis) grow out of a bulb. The plant has no obvious leaves because the onion-like bulb is comprised of compressed leaf structures. As with any bulb, the onion houses the embryo and holds carbohydrates for continued plant growth.
Climbing onion plants may grow up to 8 inches (20 cm.) across in their native habitat but usually only achieve 4 inches (10 cm.) in captivity. They produce offsets or smaller bulbs as the plant matures, which can be divided away from the parent to produce new plants. Slender stems sprout from the bulbs and branch out into feathery flower stalks. Numerous tiny 6 pointed starry white to green blooms appear along the stems.
The best medium for growing climbing sea onion is a gritty, well-draining soil mixture. If you wish to make your own mixture, combine half potting soil and half sand. Choose a pot with drainage holes, as excess moisture can make the bulb rot.
Climbing sea onions like to be in a crowded pot, so select one that’s just barely larger than the bulb. Place the container in full, but sheltered, sun or partial shade. Excess heat will cause the bulb to callus over and become dormant, while consistent even warmth and moderate moisture will allow the plant to grow all year.
Divide the offsets when they are half the size of the parent plant and pot them up in the same soil mixture.
Overwatering is a major concern with this plant. Best growth is achieved with moderate and consistent moisture, but never let the plant sit in water and allow the soil to dry out between watering. Stop watering completely when the stalks dry out after blooming in late summer. At this point, you can cut off the spent stems when they begin to dry out and brown. Resume watering when the bulb re-sprouts, generally in fall.
You can move the plant to a sheltered area outside in summer as long as the plant is kept above 50 F. (10 C.). Supplemental feeding is not a necessary part of climbing onion care. Provide the airy green stems with a support structure or simply allow them to tangle around themselves.
This is an amazing plant with a great deal of interest that is fun to have around the house, and will keep you guessing as it goes through its growth phases.
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And onions are one of the most important.
Considering I use an onion in almost every meal I cook, they are non-negotiable in my homestead kitchen.
While I haven’t yet been able to grow enough onions to last me through the entire year, I grow as many as I can in our raised bed garden and squirrel them away in the darkest corners of the basement to become the flavoring base for soups, stews, roasts, and more all winter long.
But the thing I love most about onions?
Like my all-time favorite crop (aka potatoes), they’re virtually hands-off once I get them into the soil.
Plant ’em, water ’em, and forget about ’em.
That’s how I like to roll in the garden.
If you’ve never grown onions before, it may feel a little intimidating at first glance, so I’ve compiled my best tips for growing a bumper onion crop:
They thrive in 14-16 hours of daylight and are best suited to grow in the Northern zones.
On the other hand, short-day varieties thrive in warmer regions and only require 10-12 hours of daylight. These varieties include White Bermuda, Stuttgarter, and Burgundy.
They are best planted in spring and late autumn when the dangers of frost have passed.
To start, pull out the weeds and do a little tilling. Mix and layer your raised bed soil with compost. Make sure to maintain the soil’s texture and fertility. If you don’t have any homemade compost, store-bought serves the same purpose.
Trying to weed between skinny onion shoots and weeds can be tedious as weeds always try to outdo the onion plants.
The trick here is to sow shallowly. Sowing too deep will weigh the seeds down, slowing the sprouting process. Cover lightly and keep the soil moist up until the seeds start sprouting.
At this point, it is safe to water your onion plants as required.
Sow your onion seeds shallow in a container, and lightly cover with soil. Keep the soil moist until the seeds begin to sprout. After this, you should water them until the seedlings are about 5 inches tall and ready for transplant.
As onion plants grow, so do the bulbs. The most important thing you should remember is to allow air and moisture into the roots to increase the chance of thriving. Here are some care tips to remember as well:
Watch this video from the ripe tomato farms on how to regrow onions from onion tops
And that’s how you properly grow onions, my dear green thumbs. Easy-peasy, right? I bet you will not be going for store-bought onions anymore, and all for a good reason.
Have fun trying out either of these methods and stick to the one that works best for you!
What other vegetables are you looking to growing in your raised garden this summer? Let us know by leaving a comment below!
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'Ailsa Craig' onions
Do you want to grow big onions? You need to start early. The key to growing big onions is for the plants to be large when they begin to form bulbs. Bulb formation begins as early as late April to early May in North Dakota.
We want our onion plants to have as many leaves as possible in spring. That’s because every leaf creates a ring of onion. An onion plant with lots of leaves will have lots of rings—and a bigger bulb.
Variety.We grow long-day onions in North Dakota. These onions are sown in spring and form bulbs when days are 14–16 hours long. 'Ailsa Craig' is the most widely available variety that forms giant bulbs it’s highly recommended. ‘Sweet Sandwich’, ‘Sweet Spanish’ and ‘Walla Walla’ are suitable choices.
Intermediate- and short-day varieties will begin to form bulbs earlier in spring. This is not a good thing. Their plants will be small when they begin to bulb, leading to small bulbs.
Seeds, Transplants or Sets.Seeds should be sown in flats in mid-February. Sow seeds thickly and later thin to about ½–inch apart. Clip the tops once they grow 5 inches tall.
If buying transplants, look for those that have a diameter the size of a pencil.
Sets are generally used for growing green onions, not giant onions. If buying sets for bulbing onions, look for sets with diameters of 0.5 inches or less. You may think a large set will lead to a large bulb. This is false. Compared to a small set, a large set is more likely to bloom, which leads to a small bulb.
Let’s spend a moment to understand the life of an onion plant. It lives for two years in nature. The first year it is juvenile it forms a bulb. The plant overwinters, and in the second year becomes reproductive. It uses the food inside its bulb to bloom, produce seeds (and then die). A large set is more likely to have completed its juvenile state. A cold spell in spring may trigger such a large set to become reproductive and go to seed. Think small when it comes to sets. Large sets are great for green onions, not bulbing onions.
Planting Dates. Onions tolerate light frosts and are typically planted in late April.
Sunlight. Giant onions need full sun. Sunlight is the source of energy for plants. Onions want full sun.
Soil Preparation. The soil should be well drained and loose. A sandy loam is ideal. Raised beds work well. Compacted soils will restrict bulb growth add an inch or two of peat moss, compost or other organic matter, if needed.
Spacing. Giant bulbs need lots of space. Crowding the bulbs will limit their growth. Plants are spaced 4–6 inches apart in rows spaced 12–18 inches apart. They may be planted in double rows or multiple rows per bed. If you plan to harvest some of the plants as green onions while young, space the plants 2 inches apart in the row and thin as needed.
Weed Control. Onion is one of the least competitive of all vegetable plants. You have to control weeds, which compete for water, nutrients and sunlight. Weeds also attract thrips and other pests that harm onions.
Irrigation. Onions have shallow roots and struggle in dry soil. The planting should receive one inch of water every week either from irrigation or rainfall. The availability of water is especially important while the plant is growing its bulb some growers increase watering to 1.5 inches every week during this stage. Stop watering when the tops start falling over.
Fertilization. A soil test will tell you exactly what you need. One general guide is to apply ½ cup of 10-20-10 per 10 feet of row before planting. One or two applications of urea (46–0–0) at a rate of 1/3 cup per 10 feet of row may be applied at intervals of 2–3 weeks after planting. Fertilizations in late summer should be avoided since they lead to thick stalks and poor storage qualities.
Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Source: Hatterman-Valenti, H. 2015. How to grow large onions. NDSU Spring Fever Garden Forums. Photo courtesy of Chiot's Run.
You can grow onions from seed, but it’s much easier and quicker to grow them from sets (small onions). Plant these in autumn or spring, 10-15cm apart in well-prepared, moisture-retentive, fertile soil in full sun. Keep the area weed free and water in dry periods. Harvest the onions when they’re big enough to eat or the foliage has turned brown and started to wither.
More expert advice on growing onions:
Follow our start-to-finish guide to growing onions, below.
Sow onion seed indoors as early as January, so they are large enough to plant out in spring. Sow seed in a pot or tray of moist seed compost, about 1cm apart. When the seedlings are a few inches tall, prick them out and transplant into fresh, peat-free multi-purpose compost. Once established, transplant seedlings into the garden, 10-15cm apart.
Onion sets are available to buy for spring or autumn planting. Most are heat-treated, meaning they’re less likely to bolt (produce flowers), which stops the onions bulking up. Plant onion sets 10-15cm apart, allowing 30cm between rows. Plant them just below the soil surface, with just the tips showing, in a moisture-retentive, fertile soil, ideally with plenty of well-rotted organic matter such as garden compost.
Watch Monty Don’s video guide to planting onion sets in modules:
In spring, apply a nitrogen-rich fertiliser to autumn-planted bulbs to give them a boost. Water well during dry spells and remove any flower heads that appear, as these divert the plant’s energy from bulb development, to seed production. Onions are shallow rooting, so hand weed instead of hoeing between the rows.
You may need to cover the sets with horticultural fleece, to stop birds pulling them up.
Drooping yellow foliage is the first sign of onion fly larvae, but by then they’ll already be eating their way through the bulb by the time you notice the damage. You can protect crops the following year, by growing them under fleece. Companion planting parsley among your onions can also ward off onion fly.
Onion-neck rot can be a problem in wet summers. Telltale signs are brown marks and fluffy grey mould. Don’t overcrowd when planting, and dry bulbs thoroughly before storing.
Watch Monty Don’s video guide to identifying white onion rot:
Harvest onions as soon as they’re big enough to use. The leaves will droop over and turn brown when they’ve stopped growing. Gently loosen the soil with a fork and lift the onions out of the soil, and leave them to dry on a drying rack or similar, before storing.
Peel and chop onions for soups, stews, pickles and sauces. Sweeter varieties, such as red onions, are best for using raw in salads.
Watch this 20-second video demonstration from our friends at olive magazine on how to chop an onion.
Spread onions and shallots out on newspaper or racks to dry. They’re ready when their outer skins rustle when you touch them. Hang or string them in nets in a cool, dark, dry place. They should last for months.
Bowiea volubilis has a succulent bright green bulb, resembling an onion can be up to 25 cm in diameter, that is partially exposed above the soil line. The stems produce leaves that are actually small bare branches. The roots are Fleshy, white, to 5 mm in diameter. Small star-shaped greenish or white up to 0.4 inches (1 cm) wide flowers appear in late winter or early spring. Blooms are produced only in moderate to full sun where the plant produces dozens of flowers on each shoot. The flowers have an unpleasant smell. It has black, angular-oblong, shiny seed which is 5-10 mm long. The whole plant is poisonous. It can cause contact dermatitis by touching the bulb or nausea, vomiting, abdominal pain and cramping if eaten. The plant is only severely toxic, however, if consumed in large quantities.
Scientific Name: Bowiea volubilis
Common Name: Climbing Onion, Climbing sea onions.
How to grow and maintain Bowiea volubilis:
It prefers full sun or partial shade.
It likes well-drained, organic soil. Utilize a blend a mixture of cactus and normal potting soil.
It prefers to maintain an indoor temperature above 40°F.
Water regularly during the growing season. Never allow the plant sit in water and enable the soil to dry out between watering. Quit watering completely when the vines dry out in late summer. Prune the stems when they turn brown. Resume watering when the bulb re-grows.
Climbing Onions are moderate feeder especially when grown under high light. Utilize 1/4 tsp of fertilizer per gallon of water once a week. Utilize a balanced fertilizer like a 15-15-15. Stop feeding when dormant.
It can propagate from seed, divisions, or from individual scales which once evacuated, will eventually form numerous bulbils.
Pests and Diseases:
Mealybugs seem to be a problem, particularly in older specimens that have formed a clump of bulbs. They hide in the residue of the old, dry, dead bulb scales.
Planting onion sets in the spring is a great way to both enjoy an earlier harvest, and bigger onions from your garden.
Onions can be planted with bulbs (sets), transplants, or by seed. Although seed is the least expensive way to plant, spring seeds take a long time to germinate and grow.
In fact, so much time, that some long-season onion varieties have a lot of trouble reaching full maturity by fall. It can lead to a disappointingly small harvest when planting seed onions in the spring.Onion sets are the way to go when planting onions in the spring.
It’s not that growing onions from seed is a bad idea. In fact, many gardeners grow onions quite successfully with seed in the fall. Fall seeding allows time for the onions to become established before winter. Then, as spring returns, they can continue on to grow to full size by summer’s end.
Onion seeds can also work well in the spring for those who want to grow and harvest small green onions for fresh eating. (See : Growing Onion Sets Vs. Onion Sets)
But in most growing areas, there is simply not enough growing days to start onions in the spring from seed. Not at least if you are looking to grow sizable onions for harvesting.
Onion sets develop larger bulbs than seeds at a much faster rate.
Onion sets produce onions ready for harvest quickly compared to seed planting in the spring. As much as two, to two and a half months earlier.
And that is exactly why using sets vs. seed in the spring is so important!
Onion sets can usually be found in most garden centers and feed stores in early spring. Although there are many varieties, almost all sets are sold simply as yellow, red, or white onions.
Onion sets can commonly be found in red, yellow or white varieties.
When selecting onion sets, don’t worry if the onions seem small. Smaller sets will produce large bulbs. In fact, if the bulbs used for sets are too large at planting, they often bolt before ever maturing. For that very reason, smaller bulbs are better.
How you plant your onion set bulbs depends on what type of onions you want to harvest.
If you are looking to harvest large onion bulbs, plant bulbs approximately 1.5″ deep, and 3″ to 4″ apart. This space is vital to let spring planted onion sets have room to grow.
Space onion sets
If you are, however, looking to grow spring onions from your sets (green onions), plant bulbs closer at 3/4″ apart. These onions can be harvested in as little as 4 weeks, and simply don’t need or require additional space.
Onions require loose, well-draining, and fertile soil to grow well. The loose soil helps onions to absorb moisture quickly. It also helps the onions to keep from rotting in overly damp conditions.
Onion sets can be picked early for spring onions.
Mixing in generous amounts of compost at planting is one of the best way to provide good soil conditions for onions. Compost adds nutrients to the soil, and in addition, helps loosen the soil structure. Product Link : Uncle Charlies Bagged Compost
If you are growing in extremely hard soils, or soil that has a lot of clay, adding in a bit of sand will help with drainage as well.
Although onions don’t require additional nutrients in the form of fertilizers, keeping the crop mulched will help keep moisture in, and weeds out. And nothing will keep a crop of onions from reaching their full potential like competing weeds!
Compost is the best way to prepare soil for growing onions. It helps to add nutrients to the soil and helps loosen the soil structure as well.
Mulch the soil with a few inches of straw or shredded leaves at planting time, and then add a few additional inches as the onions sprout and grow.
Here is to planting a few onion sets this spring for a great crop of summer onions this year!
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