Forcing Bulbs Over Water: A Project for the Whole Family


Forcing bulbs: as easy as 1, 2, 3! Source:

 I already explained in a recent article how to force bulbs in a pot of growing media, but you can also force them with no soil at all, over a container of water.

A hyacinth vase” is typically used for this purpose. It’s a transparent or ceramic hourglass-shaped container designed to hold one bulb. The constriction at the vase’s neck is designed to support the base of the bulb and hold it above the water so it won’t sit in water and rot. Hyacinth vases have been around since at least the 18thcentury and are easy to find in garden center that sells bulbs as well as online.  

However, you don’t actually need a hyacinth vase. You can use any container with a neck the right size to hold the bulb suspended above water: for example, a small jam jar might work.

A Great Project for Kids


Forcing bulbs over water is an easy project for children. Source:

I first experienced forcing a bulb in water in kindergarten. I was absolutely fascinated to see the plant grow from roots to bloom in such a short time. And this is something you can do with your children or grandchildren. Also, a bulb is big enough that a child manipulate it and put it in the vase. From about age six on, children are even mature enough to be able to water their sprouting bulb … under the watchful eye of a parent, of course, to remind them about regularly checking the water level.

The bulb traditionally used for forcing over water is the hyacinth (Hyacinthus orientalis). Garden centers sell them from September until near Christmas. Any bulb about the size of a hyacinth bulb could also be used instead, such as a large tulip or narcissus bulb.

Smaller bulbs, like crocus, squills and muscaris, would just fall right through the throat of a hyacinth vase, but if you look, you can find “crocus vases” online that are adapted to smaller bulbs. Plus there are lots of bottles with a constricted throat of an appropriate size. You can even grow an amaryllis (Hippeastrum) bulb over water … provided you find a container with a large enough mouth. And yes, there are amaryllis vases to be found online!

The Best Bulbs for Water Culture


Prepared hyacinths are particularly easy to force.

The best bulb for a hyacinth vase is, of course, a hyacinth, but not just any hyacinth: a prepared hyacinth. They come in all the usual hyacinth colors and are just as deliciously perfumed, but have been, as the name suggest, pretreated by gradual cooling so that they have already undergone the “cool winter” needed to encourage bloom. As a result, they don’t absolutely need a chilling period (although cool temperaturesabout 50 to 54 ° F (10 to 12 ° C)are still best). Nor do they really need to be stuck in a dark corner: you can just put them on a window ledge and let them do their thing! And a prepared hyacinths blooms quite quickly: in as little as 6 weeks, although 9 is more likely.


Paperwhite narcissus. Source:

The Paperwhite narcissus (Narcissus papyraceus and its close relatives, such as ‘Grand Soleil d’Or’ and Chinese Sacred Lily) are the best narcissus to use for growing indoors over water, as they don’t require a true chilling period either. They will take normal room temperatures, although night temperatures below 65 ° F (18 °C) are best, and bloom in 5 to 8 weeks.

Other spring bulbs (crocus, squills, muscaris, tulips, other narcissus, etc.) need serious cold (33 to 40° F/1 to 9 ° C) day and night over quite a long period: usually about 14 week, preferably in the dark in a refrigerator, cold room or barely heated garage. (See Forcing Bulbs Without Twisting Arms for more details.)

And finally, there is the amaryllis (Hippeastrum) that needs no cold or dark treatment at all, just a really big vase, coming into bloom in only 5 to 8 weeks. But forcing amaryllis over water is expensive: they’re not cheap bulbs and forced bulbs bloom only once. I prefer to grow amaryllis bulbs in soil so they can be treated not as throw-aways but as true, long-lived houseplants.

So Simple!

The technique is incredibly easy.


Just add water and place the bulb in the vase. Source: http://www.gardenersworld

Fill the container with fresh water up to the neck and place the bulb, pointed side up, just inside the container, where the neck narrows. The base of the bulb should barely touch the water. Then set the container a cool, dark place.


Roots start to form within days. Source:

Roots form quickly and reach down into the water. You can let the water level drop considerably once roots are present: they don’t have to be entirely in water, just at least dip into water. Still, take a look every three or four days, adding more water as needed, as bulbs are thirsty creatures and the container should never dry out completely.

When a healthy sprout has formed, the container is filled with roots and the minimum number of weeks has elapsed, the plant can be exposed to light and heat. Flowering then occurs quickly: often starting in barely a week.

When the bulb stops blooming, clean the container and put it away for next year, then drop the bulb into the compost. Being grown over water will have completely exhausted it and it won’t bloom again. Don’t even think of adding fertilizer to the water to “feed” the bulb for another flowering: it will be in no better shape … and your container will quickly fill with algae.

Forcing in Pebbles and More


You can use pebbles or the substrate of your choice. Source:

You can also easily force bulbs in pebbles or any other fairly inert substrate, such as gravel, clay hydroculture pebbles, seashells, marbles, etc. This is, in fact, still considered forcing over water, as the substrate provides only holds the plant up: it’s the water that makes it grow.

Any decorative container with no drainage hole will do, although a transparent container will make your life easier, because you’ll not be able to see the roots growing (fascinating) and also better monitor the water level. Just drop substrate into the bottom of the container to a depth of anywhere from an inch  (2.5 cm) to 5 inches (13 cm) or more. Roots will grow into this layer.


Fill the bottom with substrate, then add bulbs. Source:

Set the bulbs on the substrate. For the most beautiful flowering, fit as many bulbs into the container as it can hold and, although you’ll read otherwise elsewhere, yes, the bulbs can touch! For added solidity, fill the interstices between the bulbs with more substrate, leaving on the tip of the bulbs exposed. Now add water up to the base of the bulbs and place the container somewhere cold and dark. Soon roots will form and the forcing is underway!

All that’s left is to check every now and then, topping up with water as needed, then bring the pots into the light and warmth when the bulbs are ready (see above).


The Paperwhite narcissus is the most common bulb grown in pebbles. Here, in seashells! Source:

All bulbs suitable for forcing over water are also suitable for pebble forcing, but the Paperwhite narcissus is the most popular for this use.

There you go! A simple little fall project that will bring gorgeous (and often scented) bloom into your home or office during the dark days of winter and early spring. Why hesitate? Just do it!


Forcing Bulbs Without Twisting Arms


Forcing bulbs (here, Siberian squills) simply means getting them to bloom indoors before their usual season. Source:

I don’t like the word “forcing.” Although, in a horticultural sense, it simply means stimulating a plant to bloom ahead of its usual season, it somehow sounds like you’re using some sort of nasty or painful process to get them to bloom. But you aren’t. And forcing is so easy to do.

You can force perennials and shrubs to bloom early indoors, but mostly forcing is used on hardy bulbs. These are the same bulbs you normally plant outdoors in the fall for bloom next spring, but instead of planting them in the ground, you pot them up and grow them indoors.

Fall is the season for forcing bulbs. You can force bulbs left over from your fall plantings or make a special trip to the garden center for a few more. Note that bulbs may be on sale in the late fall: a good excuse for trying your hand at forcing.

The How-To


Pack ’em in: the more bulbs, the better the show! Source:

Forcing is pretty simple. Take a good-sized pot (at least 8 inches/20 cm in diameter) and fill it to ¾ of its height with your favorite potting soil (tip: potting soil will be easier to handle if you moisten it ahead of time). Place the bulbs on the mix, flat side down, pointed side up. Don’t be stingy: stuff as many bulbs in the pot as you can. And yes, in spite of what most references say, the bulbs can touch. The more bulbs you fit into the pot, the better the effect will be!

Can you mix different bulbs in the same pot? Sure… but don’t expect them to bloom all at the same time. That almost never happens!

Next, cover the bulbs with potting mix. It doesn’t matter in the slightest if the tip of the bulb pokes through, but the bulbs will be sturdier if the lower, rounded part is well covered. Finally, water well.


Forcing hyacinth bubs over water.Source:

You can also force bulbs over water alone if you want to, using a hyacinth vase or a decorative cachepot with no drainage hole and stones or marbles. Just make sure the base of the bulb barely touches the water below. I’ll write more about this is an upcoming blog.


Your bulbs will need a prolonged period of cold. Source: Clair Tourigny, Les 1500 trucs du jardinier paresseux

Now comes the important part: the bulbs have to undergo a prolonged period of cold temperatures in order to bloom. That’s because they come from climates where there is a long, cold winter and, without a pronounced cold period, they won’t know when to flower. So, pack your pot of bulbs into a plastic bag (so it doesn’t dry out too quickly) and place it in a refrigerator, a barely heated garage, a cold room or other location where the temperature will remain above freezing, but below 50˚ F (10˚ C).

In fairly mild climates (zones 6 to 8), there is another option. You won’t need a plastic bag this time: just place the pots of bulbs in a trench 12 to 15 inches (30-40 cm) deep, filling it with mulch and mounding up a further 6 inches (15 cm) of mulch on top. Thus, you can easily dig them up whenever you need to.

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I just know I buried the pot around somewhere around here! Source:

This could theoretically work in cold climates too, but it’s very awkward when the mulch is frozen and the ground covered with snow. Also, in any climate, beware that voles and other rodents may discover bulbs buried in a trench. That’s why I prefer keeping mine safely indoors.

In truly warm climates (hardiness zones 9 and above) or anywhere else winter soil temperatures don’t remain below 55˚ F (13˚ C) for months at a time, you won’t be able to put potted bulbs outdoors either. You really will need a refrigerator to get your bulbs to bloom!

The Long Wait


Patience is required. Source:

Bulbs need a long period of cold. 14 weeks is the norm (mark it on your calendar!), although some bulbs, such as crocuses and grape hyacinths, only need 10 weeks, hyacinths are usually fine with 9 weeks and a few of the later tulips prefer more: 15 to 16 weeks.

Of course, that’s a minimum. You can prolong the cold treatment if necessary, pretty much as long as you want to (I once forgot a pot of tulips in my fridge and pulled in out in July: they bloomed beautifully!)

During this time, water as needed: the bulbs are not actually dormant, but growing in preparation for their upcoming bloom. So you may need to give them a good watering after a month or so. Do let them drain well, though.


When new sprouts appear and the pot is full of roots, you can start exposing the bulbs to light and warmer temperatures. Source:

When new pale yellow shoots appear and the pot is filled with roots, your bulbs are probably ready, especially if you have patiently waited the required 14 weeks. If so, remove the bag if there is one and put the pot in a cool but sunny spot: an east-facing window, for example. Leaves and flower stems emerge very quickly and the bulbs will soon be in bloom. Give the pot a quarter turn every three or four days to keep the stems growing straight and keep on watering them as needed. Cool temperatures are not absolutely essential and if you place the bulbs in a warm room, they’ll bloom anyway, but the stems may etiolate (stretch) and will then need staking.


Muscari (grape hyacinths) in bloom on a window ledge. Source: 20181105J

The show will be spectacular, but fairly short: a week or two. Ideally, you’ll have potted up plenty of other bulbs so you can pull out a pot or two every week and thus ensure continuous bloom.

Afterwards, you can simply compost the bulbs if you want, but you can also try planting them in the ground once the soil has thawed. They will bloom again in coming years, although they may need a year or two to adjust. Tulips are an exception: they don’t recuperate well from forcing and it is rarely worth doing anything but composting them.

It’s not worthwhile forcing the same bulbs a second time: forcing exhausts them. Instead, use fresh bulbs every year. Grape hyacinths (Muscari) are an exception: you can force them year after year.

Which Bulbs to Force?


Tulips tend to etiolate when forced, so grow early varieties that are naturally shorter. Source:

You can force any spring flowering bulb, but in a given category, early-flowering varieties usually give the best results. That’s because they tend to be shorter and therefore, even if they become a bit etiolated (which is often the case when you force bulbs at room temperatures), it doesn’t show as much.

Here are some examples of bulbs that are easy to force:

  1. Anemone blanda
  2. Chionodoxa: any variety
  3. Crocus: ‘Yellow Giant’, ‘Joan of Arc’, ‘Remembrance’
  4. Iris reticulata ‘Harmony’, ‘J. S. Dijt’
  5. Hyacinth: ‘Blue Jacket’, ‘Delft Blue’, ‘Innocence’, ‘Queen of the Pinks’
  6. Muscari: any variety
  7. Narcissus: ‘Carlton’, ‘February Gold’, ‘Peeping Tom’, ‘Tête à Tête’, ‘Unsurpassable’
  8. Snowdrop: any variety
  9. Squill: any variety
  10. Tulip: single early, double early and triumph tulips are best, including ‘Brilliant Star’, ‘Christmas Marvel’, ‘Couleur Cardinal’, and ‘Diana’.

Special Cases


Paperwhite narcissus: the fastest bulbs to bloom. Source:

Paperwhite narcissus (Narcissus papyraceus, syn. N. tazetta) don’t need a cold treatment to bloom and are the fastest of all bulbs to bloom. Plant them in early November and you’ll have flowers for Christmas!

There are also “prepared hyacinths” whose bulbs were specially treated so they can bloom without a cold period, but plant them fairly early (certainly before Christmas), as the treatment “wears off.” Note that they cost more than regular hyacinths.

Forcing bulbs: so easy to do. Why not give it a try this winter?

The Little Bulb That Conquered China

20171108A Victorcny2010, WC

The Chinese sacred lily (Narcissus tazetta chinensis): quite possibly the world’s most widely grown bulb! Source: Victorcny2010, Wikimedia Commons

If any narcissus has a story to tell, it’s the Chinese Sacred Lily. Odd name for a narcissus, you say? Indeed, and that’s part of the story of this fascinating bulb that became China’s darling over 1,000 years ago.

The botanical name of the Chinese sacred lily is Narcissus tazetta chinensis (some authorities prefer N. tazetta orientalis). Each bulb produces 4 to 6 flat green leaves and a stem up to about 16 inches (40 cm) tall with up to 8 honey/citrus-scented white flowers with a golden-yellow crown in the center. It’s closely related to the popular Paperwhite narcissus (N. papyraceus) and indeed, the latter was long considered a form of N. tazetta. After all, both are native to the Mediterranean region and are among the few subtropical narcissi (most narcissi and daffodils are hardy plants). The two do, however, differ by flower color (the Paperwhite narcissus, as the same suggests, is pure white) and by the number of chromosomes: the Chinese sacred lilies are diploids and have 11 chromosomes while Paperwhites are tetraploids, with 22 chromosomes.

Small Plant, Long History

The Chinese sacred lily may have left its first mark on history as the rose of Sharon mentioned in the bible. It’s also one of the plants that might be Matthew’s famous “lily of the field.” That would make sense, as it does grow wild in Israel and indeed throughout the Middle East. However, there are many other candidates for those both, including anemones, poppies, gladioli and crocuses, and which plant was actually referred to will probably never be known.

But how did it get from the Middle East to China? And so long ago? (It’s mentioned in Chinese scripts dating back to 863.)

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The Silk Road. Source: Wikimedia Commons

The Chinese sacred lily is believed to have traveled by caravan over the Silk Road. Some 1200 years ago, some enterprising camel driver probably felt that this winter blooming bulb with its beautiful white and yellow highly scented flowers might be of interest to the Chinese. To make things easier, the bulb remains fully dormant for 8 to 9 months each year and is therefore easy to transport. Carrying it 4,000 miles (6,400 km) over the Silk Road by camel caravan would not have been a problem.

Another theory is that it was instead Arab or Persian traders who brought it to China over ancient sea-trading routes.

Either way, it was being grown on a large scale in China by the beginning of the Song Dynasty (960). By then, it was already recognized as one of the symbols of Chinese New Year, because not only does it blooms naturally at about the right date (Chinese New Year takes place between January 21 and February 19, varying according to the Chinese lunar calendar), but its golden-yellow central crown is a symbol of good luck and prosperity. If it blooms on Chinese New Year, it is said to bring extra wealth and good fortune throughout the year. It remains a popular New Year’s plant to this day and in fact, is so widely grown in Asia it may well be the world’s best-selling bulb.

In China, Korea and Japan, the bulb has also escaped from culture and grows wild in several regions. Botanists who found it there assumed it was a native, hence the botanical name N. tazetta chinensis.

On to America

But the Chinese sacred lily had not yet finished its wanderings.

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Chinese New Year in 1850’s Oregon featured the Chinese sacred lily. Source: Peter Britt, Southern Oregon Historical

Chinese workers brought it to North America during California gold rush (1848–1856). It’s still found there, naturalized in fields, abandoned gardens and old Chinese cemeteries in and around gold mining areas. It is also during the gold rush that it was first called Chinese sacred lily, a name still used today as a cultivar name. (The Chinese themselves have many names for this bulb, including shui xian, shui xian hua, lien chu and seui sin faa, depending on the local dialect.)

Why lily and not narcissus? My guess is that gold miners probably weren’t too knowledgeable about horticulture!

Growing Chinese Sacred Lilies

Unless you live in a mild climate (zone 9 or warmer), this is one narcissus you won’t be able to plant outdoors. Most readers of this blog will have to grow this tender bulb indoors, protected from severe cold.


You can grow the Chinese sacred lily in a bowl of decorative stones if you want to. Source:

It couldn’t be easier to grow. Just place 3 to 5 bulbs in a 6 to 8-inch pot (15 to 20 cm). You can plant them in potting soil in a pot with drainage holes or even in decorative stones in a cachepot. Bury at least the base of the bulb so it remains solidly upright, but you can leave the top part exposed. Water well and, if possible, place the pot in fairly a cool place, at less than 65 ° F (18 ° C) at night. You could, for example, place the pot in the window of a barely heated garage, a protected veranda or a cold frame. Or set it in the refrigerator for about 3 weeks until plenty of roots have formed, before exposing it to more warmth. Even if you can’t supply cooler temperatures, the bulbs will still bloom, but will then tend to etiolate (stretch) and you may need to stake the stems. Giving it as much sunshine as you can is another way of keeping the plant more compact.

Normally, the bulbs will bloom 3 to 8 weeks after planting, depending on when you plant them. (The later in the season you pot them up, the faster they come into bloom.)

While They’re in Bloom


Chinese sacred lily in bloom. Source:

Just keep their roots moist, watering well when the soil is dry to the touch. The Chinese sacred lily can easily tolerate normal indoor temperatures when in bloom.

After Flowering

Most authorities suggest simply tossing the bulbs after they bloom, claiming they won’t bloom a second time, but I beg to differ. That may be true if you grow them in stones where they won’t be able to recuperate the minerals they lost when they flowered, but if you plant them in pots of soil, you can bloom them again and again. Just follow the plant’s normal growth cycle.

For example, continue to water as long as the foliage remains green. Also, after flowering, start fertilizing the plant regularly. When the leaves finally do turn yellow, which can take two months or more, stop watering and fertilizing and allow the bulbs to go dormant. You’ll probably want to hide them from sight during spring, summer and early fall, but you don’t have to. Certainly, you don’t have to store them in the dark, another common misconception about dormant bulbs. (The plant will be dormant: do you think it cares whether it’s in the dark or in the sun?) Then, late next fall or early next winter, from November to January, start watering again and the plant will grow back and quickly come into bloom.

In Bloom for Chinese New Year?


Chinese sacred lilies on sale in Hong Kong at New Year’s. Source: Victorcny2010

Cultivating Chinese sacred lilies exactly on time for Chinese New Year is quite a challenge, as the holiday changes date according to the lunar calendar. Commercial growers of the bulb invest a lot of effort in precisely controlling growing conditions in order to have it bloom at exactly the right time. You can’t really expect to do as well as they do under home conditions. However, if you start watering about five weeks beforehand (Chinese New Year will be February 16 in 2018, so in early December 2017), you ought to be quite close.

Personally, I don’t aim for a particular date. I’m happy to see this bulb flower whenever it wants to and I just start watering when I see the first signs of green growth at the tip of the bulb.

The Chinese sacred lily is available from mail-order bulb suppliers and garden centers. Indeed, if I’m writing about it right now, it’s because I was able to buy a pack in my local garden center just this week. Look for it: it’s a most interesting plant with quite a history and certainly something to charm the earliest days of winter!20171108A Victorcny2010, WC

The Indoor Narcissus


Paperwhite narcissus

Not all bulbs sold in garden centers in the fall are supposed to be planted outdoors, at least not in cooler climates.

The first exception is the amaryllis (Hippeastrum), but few gardeners make the mistake of trying to plant it outdoors. It seems that even novices understand that the amaryllis is an indoor bulb. But the other exception is the Paperwhite narcissus. Unfortunately gardeners from cooler climates often do plant it outdoors, not realizing that it isn’t hardy. And then nothing comes up in spring. Here’s why:

Paperwhite narcissus (now officially called Narcissus papyraceus, although it is still sold under its old name, N. tazetta) originally comes from southern Europe and northern Africa, a warm temperate to subtropical climate. Compare that to most other narcissus which hail from climates with cold, snowy winters: that’s quite a difference! Paperwhite narcissus can be planted outdoors, but only in mild climates (zones 8-11). It is simply not hardy in temperate regions.

Garden centers sell Paperwhite bulbs for forcing, that is, for growing indoors. And usually there is a photo accompanying the bulb showing it growing indoors in a pot. Still, it is a narcissus, so mistakenly planting them outdoors is not impossible.

These days, there are many cultivars of Paperwhite narcissus on the market. I’ve seen the following names: ‘Galilee’, ‘Ziva’, ‘Nomy’, ‘Omri’, ‘Yalel’ and ‘Sheleg’. All are single-flowered narcissus with small, clustered, highly perfumed white flowers. In fact, they all look pretty much the same. The named cultivars are just a bit more compact and faster to bloom than the species.

How to Grow Paperwhite Narcissus

Paperwhite narcissus is certainly easy enough to grow. And it blooms quickly, too, often in as little as 5-6 weeks. Here’s what to do:


Paperwhites should be grown in pots.

Plant four or five bulbs in a 6 to 8 inch (15 to 20 cm) pot. You can use potting soil or decorative stones. Bury the rounded part of the bulb: you can leave the tip exposed if you prefer. Water well and place in a sunny spot at cool temperatures, if possible. Nights below 65˚F (18˚C) are ideal.

Some authorities suggest you put the bulbs in a dark spot a first and there’s nothing wrong with that, but it really isn’t necessary. Certainly they should be moved to full sun as soon as leaves start to appear… and that can be within days of planting the bulbs.

If you can’t give the bulbs cool night temperatures, don’t be too concerned. The plant will flower well under warm nights too, but then tends to etiolate (stretch) and thus may need staking. Intense sunlight will help keep the plant more compact if you have no control over the temperature.

20151022DOr get it drunk! Studies show that watering Paperwhite narcissus with a very dilute solution of alcohol will give a more compact plant. You choose the drink – vodka, gin, rubbing alcohol, etc. – but is has to be distilled alcool. Avoid beer and wine: they contain too much sugar and that can stimulate the growth of fungi. Dilute the alcohol at a rate of 1 part to 8 to 10 parts water.

After Your Paperwhite Blooms

After flowering, you might as well toss the bulbs into the compost bin, because they won’t bloom again. Or at least that’s what I was always told.

I’ve discovered that this is not really true, that it is possible to recuperate Paperwhite narcissus bulbs and see them bloom again. Here’s what to do.

When the flowers have faded, continue to water the bulbs through the winter and spring, preferably at cool temperatures (they will tolerate up to about 40˚F/4˚C). Give them full sun and fertilize regularly. Flowering causes the bulbs to shrink in size; it takes sun and minerals to get them to fill out again. Don’t cut off the leaves as long as they are green.

When summer comes, you can put the bulbs outside. My experience is that the foliage lasts a long time, until July, sometimes even August. When it finally does start to turn yellow, stop watering. You can leave the bulbs in their pot or, if you prefer, dig them up and store them dry in a paper bag or a cardboard box.


These ‘Galilee’ paperwhites are blooming for a second time.

Late in the fall, although you haven’t watered for months, small pale yellow shoots will appear at the tip of the bulbs. This is sign they are ready to grow again. Pot them up again if necessary and start to water them, giving them the treatment described above. Soon your Paperwhites will be in bloom again.

I found I could get my Paperwhites to rebloom once for sure, usually twice. After that, the bulbs had multiplied so massively that the bulbs were too small to bloom. I’ve never gone further than this stage and simply composted the small bulbs.

So, yes, you can recuperate Paperwhite bulbs… but it is much simpler to buy fresh bulbs each fall!