Ok, I get it. Found answer from some 'Tulip Expert:'

Q. Why can a tulip bulb freeze under the soil during the winter and still bloom in the spring? Is it because the temperature under the ground is always warmer than 20 degrees?

A. Yes, you are correct! The air temperature is much colder than the soil temperature. The soil temperature near the surface may be 32 degrees in the winter, but does not vary much from that, especially if the ground is covered with snow. A local weather station may be able to give you actual soil temperatures so you can look at the variation ( or lack of) day to day in the winter. The tulip bulbs do not freeze, if it did get to 20 degrees they would freeze and die.

Interesting. I had wondered about this myself.... Thanks for posting.

For your second question, I am in MA near the NH border and just got a some extra bulbs recently and am planning to plant them this weekend even though I finished my regular planting of bulbs earlier in November. I think I read that if planted late they may be shorter next year but will recover the next season. In my case having gotten the bulbs cheap if they don't make it no great loss....

Unfortunately the tulip expert is wrong. Tulip bulbs, and other bulbs too, can take soil temperatures far below freezing. This is obvious if you think about something like a Crocus, an inch or two below the surface in zone 4. It is going to freeze and freeze hard! The soil in some colder areas where tulips grow will freeze down to two feet or more.

The correct answer is that hardy bulbs which are rooted will not freeze, subject to their hardiness limits, while those which are not rooted will freeze and die at only a little below 32F. This is why it is important to get your bulbs into the soil late enough that they don't grow excessively but early enough that they can develop roots before they freeze. Not usually a problem for tulips since the soil 8" down will not freeze for ages after the surface becomes unworkable, but worth remebering for bulbs planted nearer the surface.

Shrubs is so right. Heck, we are often ice fishing in late Dec here, and that is with at least 6 inches of ice. That's even b4 the really cold temps hit in Jan and Feb.

Sue

No, they are not frozen deep in the ground. It is still warmer in soil than ambient temperature. You cannot put them in the freezer; but try it anyway.....just to prove me wrong. Even the Dutch advise against it.

Northern Indiana (zone 5 and I am 5b), has the ground freeze to a depth of 6 to 12 inches, and in extreme cases 2 feet.

The bulbs are in frozen ground, and are frozen themselves.

Do they survive it? Yes, if hardy to that zone. I've never lost a daff due to freezing ground temperatures.

I've used a pick ax to plant when it was 'really' late in the season.

No, they are not frozen deep in the ground. It is still warmer in soil than ambient temperature.

Did you even read what I wrote?

Besides, the northern California coast is hardly the place to be advising people in the northern plains on whether their soil freezes or not ;)

I believe in our area water companies bury their water line at least 18" to prevent freeze, farther north it is even deeper. Frankly, I would be shocked if it really freezes that deep here, but I'm sure it would freeze several inches, and we don't get enough snow cover to help.

Even though the ground is frozen, the bulb is not. That's not saying the bulb is warmer than the ground...it's saying that the freezing point of water solution in the bulb's cells is lower than the freezing point of straight water.

Just as we know dissolved salt will depress the freezing point of water, so will dissolved sugars and carbohydrates. The bulbs increase the concentration of dissolved solids as winter approaches to depress their freezing point.

I don't know what the actual soil temperature tulip bulbs are hardy to but my MIL's muscari in Edmonton crowded themselves up to the surface and they still survive a snowless -30ºC.

Simon

Besides, the northern California coast is hardly the place to be advising people in the northern plains on whether their soil freezes or not ;)

Well I guess you told me, didn't you?

Ever hear of the Donner party? Look that one up.

Isn't the Donner party the wagon train group which was trapped on the Plains side of the main mountain range just as winter closed in, and had some particularly hard country to cross to reach mining camps and ranching settlements on the California side?

If we're thinking about the same folk - are the inland foothills of the Sierra Nevada climatically similar to the coastal areas of California over winter?

California climate is influenced by the proximity to the Pacific ocean and/or the elevation of the land. Below 2500 feet it is very rare for the ground to freeze. Al

http://en.wikipedia.org/wiki/Donner_Party

All land masses are affected by water. That is what the whole global warming thing is about, ice caps melting and casuing warmer temps all over. This is happening faster than we would wish, and the weather all over the world is no longer typical. It is estimated that in less than 50 years' time we may have to draw up new maps.

Yep. Northern CA can get mighty cold in parts though.

Goodness, y'all have refreshed my memory! Even if I can never grow a tulip, I can never live anywhere but hot old Texas!

We gripe if it gets down to 40 degrees, get downright mean if it freezes. I have lived all over this country, from Upstate NY, to Marquette MI, to Oregon when I was a kid. I lived all over the world, and most of those places were cold. I cannot live in cold weather. I jus' CAIN'T!

We are down on the coast, in zone 9. It is taking a lot of research to find bulbs that will grow here and return. Some are just treated as an annual, but I am so pleased to have them at all. The cost is justified.

We did some chipping of bulbs in a propagation class, and I was surprised to learn that the insides of those bulbs are very gooey and sticky. I am not surprised they don't freeze. The juices in them is not at all like water.

Janie

Actually, the Dutch have a flowering process called "Ice Tulips" which was used extensively to produce cut tulip flowers in the summer and fall; it's not used as much now because flower bulbs are available from growers in the southern hemisphere in our spring for commercial forcing for the cut flower industry later in the year. Still, it's an interesting process:

You chill the dry bulbs at ~45F for 4-8 weeks, much like you would prior to normal forcing; however, after this time, you then either plant the bulbs or store them dry in peat and lower the temperature to just below freezing (-2C is the minimum used commercially). The bulbs can be kept dormant for months at this temperature, and then brought out to flower over the summer and into the fall.

I tried this last year with a few bulbs each of six different tulip varieties, stored dry in peat until mid May, when I planted them, kept them cool to root, and hoped for flowers. Only one variety, Claudia (lily flowering) bloomed 4 of 6 bulbs; many others grew leaves and buds, but in all the other cases, the buds were blasted. One problem is that I wasn't able to keep them at -2C; my deep freezer has two compartments, and the warmer one was around -4C, and may have varied too much for most of the bulbs. Still, almost all of the bulbs survived.

Here is a link that might be useful: Ice tulip reference

little dani

I know they're not quite the same as daffs and snowdrops, but some of the species tulips and many of the South African bulbs, should do well for you in your version of zone 9.

Still like a touch of frost, but if it's thicker than 'breaks when poked with a finger' I'm not impressed either!

Hopflower, any comparisons you are trying to make are not valid. Most obviously of course, the Donner Party were trapped in the mountains not all that far from Lake Tahoe, whereas you claim to live way on the other side of the state, ocean-side of the coast range. Even the higher parts of the Sierra Nevada are not really comparable to the northern tier states. Conditions in winter can be atrocious from high snowfall, high winds, and cold nights, but daytime highs get well above freezing on most days in winter, and the ground under thick snow freezes only very slowly.

Frost line data for the construction industry are widely available and give an idea of how deep the soil may freeze, at a maxiumum. Frost lines vary from a couple of feet in places like Missouri, to four feet in states like Minnesota and Michigan. By comparison, building codes I found for Lassen County (not far from the poor Donner folk) shows a frost line at 18". You should only expect the soil to freeze to half those depths in a typical winter.

Although the lowest temperatures we get in England are not much colder than those in somewhere like Marin County (sunset 15 or 16?), we do get occasional extended spells below freezing day and night where the soil freezes a few inches deep. Mostly the soil here is unfrozen in winter, or just a thin crust freezes and thaws each day.

Actually anything I say is extremely valid; I am rather known for being reliable. I did not say I lived on the other side of the state; and I too have relatives in the U.K.

But thanks, anyway.

I am going to let you have it your way, though. I don't like arguing with people over silly things like where I live and where I am from and where I have been. It just does not interest me.

I'm still confused. I do know that the ground in central IL. has frozen 3' down in the late 70's because we had a water line to a stable freeze solid. Laughing...it made quite an impression because we were carrying water from the bathtub, through the house and probably 200 yards to the stable to give water to 16 horses! We got rid of the horses shortly after that.

So...what's the story...tulips die in that type of environment? I don't think so...ours bloomed.

Lilies,

Yes, you are right about them not dying...and about how the ground freezes quite deeply here. Many bulbs are hardy in our colder zones...tulips, daffs, crocus, hyacinth to name but just a few.

Now cannas, or dahlias, elephant ears, glads are another story.

Sue

I was about to post my experience with frozen tulip bulbs as a new thread, then came across yours, mmqchdygg. I force tulip bulbs every year, storing them in the stairwell of my basement, where the pots have never frozen solid for any period of time. This year, we've had three (going on four) weeks of subfreezing temps, and I'd been fretting about the pots for a while, but too lazy too haul them into the warmer basement. After a couple and a half weeks of the deep freeze, and considering the amount of money I'd sunk into of all my catalog ordered babies, I thought I'd better check them. The pots were frozen solid - really solid. But after they thawed for a few days, the shoots started popping up, and all of the varieties (except one parrot) seem to be doing very well. Blooms are still a long way off, but if early foliage vitality is any indication, they'll be fine. So I think that my hunch and rationale for being too lazy too long was accurate - frozen tulip bulbs can make it through a deep freeze quite nicely. This is totally against the grain of received wisdom.

Good luck,

cranebill

dygg.....I cant explain in botanical terms what happens to a bulb, planted at the correct time, and its developing roots so that it goes into the freezing weather of a northern winter and experiences no problem.

In layman's terms.....the bulb develops roots from the cool weather that is in the ground. Once with roots, something magic happens to the inner tissue of the bulb.
Remember, the hardy bulb has everyting in it that is the plant...everything. Stem, roots, leaves, flowers....are all in the bulb when you plnat it.

When the roots form, the exterior of the bulb tissue puts up a kind of armour....nothing can harm it...not even down to 40 below zero.

But, without roots, the armour does not develop...and the bulb is left to try to sustain itself.....which it cant....because it doesn't have the protection.

This is why tulips....et al...are put intot he ground when they are. Delaying the proper time, the bulb is left open to possible harm. As long as the bulb can be put into ground that enables it to produce roots, then it will survive.

Want to try something: Put a bulb into the freezer of your refrigerator....then remove it in the spring.
But hold it over the garbage can.
Put a bulb into some soil and put that into your refrigerator...not the freezer...and water it as needed, keep it away from your crisper...and in 14 weeks take it out and give it sunlight. Watch it bloom.

Actually, it's not so much armor but a change in the chemistry of the bulb itself: starches are converted into sugars, and the chemical changes allow the bulbs to remain below freezing for extended periods of time. The sugars act like antifreeze to prevent ice crystal formation in the bulb tissues. Actual minimum temperatures vary by species and variety, but I doubt any tulip bulbs will survive in pots above ground at -40F or even -20F for extended (i.e., more than an hour or two as the minimum overnight temp) periods of time.

I've attached a link to some of the research that's been done on sugar production in tulip bulbs; it's quite amazing how complex these biological processes are.

Here is a link that might be useful: Carbohydrate Status of Tulip Bulbs during Cold-Induced Flower Stalk Elongation and Flowering

We grow tulips in raised planters. A couple hundred early tulips planted in October that we then compost after May blooming. We then use the planters for other annuals.

This is zone 3A (minus 30c).

Other bulbs that are close to the surface (our native wood lilies) and even bulbs on the surface (Egyptian walking onions) do fine and thrive. The only hardy bulb that is 'iffy here is the hyacinth. It will bloom the first year but then is moody after that.

plantcompost,
How large are your planters and how tall are they above the ground?
I planted tulips and many other minor bulbs in half whiskey barrels one winter. I surrounded the barrels with bags of leaves. The bulbs froze and turned to mush in spring. Not a single one survived or bloomed. :-(

I've tulips growing in squares made of 2' by 4' garden ties. These are about 2' deep and sit on a section of the concrete driveway. I plant the bulbs 8" and put chicken wire over them to keep out the critters. These tulips are the first to come up as the soil thaws quicker than the the soil in the gardens. I doubt if cold is much of an issue but freezing and thawing would be the reason for mush. Anything that's planted above ground needs to be allowed to freeze good and solid before it's wrapped in anything and then remain frozen. I grow crocus, lilies, scillas, pushkinias, galanthus in pots and store them on the northwest side of the house where they keep cold and shaded all winter. I keep pots of tender roses, tender grasses and similar marginal plants also on the north side but bury these in a couple feet of leaves in December after a week or so down below minus 10c. Be sure to keep them out of direct sun of any type as its surprising how warm a pot can warm up especially starting this time of year when sunlight increases and spring-like days start their teasing.

My daughter is getting married in May, and as favors she wants to give the ladies each a daffodil in a pot. This meansi have around 40 individal ones to plant, and am wondering if it is possible to freeze dfodil bulbs now and plant them in April?

Does anyone have any advice?

Regards
Richard