Mary, burying your pots outside would not be practical for you in Anchorage. Now, when we say bulbs can go below freezing, that's true, but there is a limit and at some certain point damage will begin to occur. For me, I don't like to see my soil temperature go below 25'F for very long--certainly no more than a few days. And for most people south of the Canadian border, that's easy to maintain with burying pots and mulching. Now, Asiatics can withstand colder winter soil temperatures far better than Orientals, OT's and Trumpets, and for that reason, Asiatics dominate the lily market in Canada. And, you don't have to go too far north into Canada, if you want to grow Orientals and OT's and Trumpets, etc., then one has to do exactly what you're doing---growing in pots and bringing them into an unheated garage for the winter. I would think you could plant your Asiatics in the ground and just mulch good for winter.

Now, let me try and explain something. The bulbs we buy as gardeners are in a segment called the 'dry bulb' market. Now, think: dry bulb, dry bulb, dry bulb. Think about how long these bulbs hang on the display racks at a big box store without growing--even at a warmer store temperature. Storing your bulbs in dry pots is very similar. The fact that your bulbs are surrounded by dry soil is a good thing; it prevents the bulb from drying out or becoming too dehydrated while at the same time absorbs moistures and gasses your bulbs give off during the winter in storage ( remember, lily bulbs are not really dormant during this time, there's actually a lot going on, including bud formation ). Another reason to keep bulbs dry in pots over winter is to reduce the risk of certain soil pathogens like fungus. And where you have fungus, you create an environment for bulb mites--the two often go hand in hand. So, plenty of good reasons to keep them dry.

And, now, for the bottom line---you knew this was coming. As I believe Rick said, and, I'll say it my way too: it wasn't the 45-50'F temperature that caused your lilies to start growing, it was your last and frequent watering. Had you not watered these at all, they would have not started growing until their internal time clock told them to. Additionally, the 45-50'F vernalization temperature, while, not optimum, should be cold enough to set good bud count on most OT's and LO's and LA's as you already know from your own experience. Asiatics will require the lower temperature. Just a little improvement to get the temperature down would be better and with very little effort with something like Rick's suggestion. I suppose somebody will jump all over me if I don't say it, so a light watering in mid-late Janurary is ok--just use common sense, too little is better than too much.

And don't even think about the extra monkey work of burying pots outside.

Lorn, are you seeing that Anchorage, Alaska is USDA zone 5? There are lots of differences due to latitude and geography, but temperature minimums are much like yours, yes?

While I wholeheartedly agree with all your premises, my conclusions are different. I think the soil temps in zone 5 Anchorage are probably like mine in zone 4 Minnesota.

We were both writing at the same time, Lorn, so these are my thoughts:

This past fall I harvested several dozen mature asiatic lily bulbs from a few hybridizing efforts. I deemed them rejects and they were destined for culinary consumption. When I dug them, all the soil was shaken off and piled into open plastic pots (with holes on the bottom).

After a week, I tucked some cellophane wrap over the tops, to prevent over-dehydration. Cellophane wrap (Glad Wrap, for instance) still allows for some gas and water vapor exchange, but prevents most of it. I let them sit in the garage here in zone 4 through the winter. I kept a thermometer nearby, as the question of minimum temperature survivability had me wondering. Well, I chickened out after four days with minimum temps of 15, 12, 12 and 14°F. Temperatures were below zero outside, and kept descending in the ensuing days, so I left the bulbs in the garage, but put them inside styrofoam coolers. The temp inside the cooler never went below 11°F. Bulbs never actually froze. Since then, they have thawed(above 32°F), and I even had brought a couple inside the house after the "big freeze test" and let them be overnight so I could examine them. Bulbs were nice and firm without any visible damage. If there was any damage to how growth continues into the spring, I can't say.

What does this mean? Maybe a lot, maybe not much. First realize these tested bulbs were asiatic hybrids, not orientals, trumpets, species or other kinds. Even within the asiatic group, there are lots of differences, and it's likely these differences will be reflected in cold tolerance, too. Realistically, I would guess this means that asiatic hybrids can survive soil temps of 18-20°F. Actually it may be even lower, since I didn't test to lower temps. Regarding low temperature tolerance of plants in pots, I've done a lot of impromptu investigation over the years with alpine and lower elevation plants of many genera. I have been pleasantly surprised at their tenacity for life. Remember though, that these lily bulbs were slowly acclimatized to the cold temps, and ever so slightly dehydrated. Also critical, is that these lilies were at rest, not actively growing. The ones sprouting in your garage now, Mary, would easily be damaged at 30 or 32°F.

But next year you will be able to sink your pots in the ground outside, best on their side as Lorn does, put mulch over them after the ground freezes, and leave them that way until early spring. Or you could do as Lorn says, with pots in the garage. I did say your garage was too warm, but I should have said that that is a complicating factor. Following Lorn's advice for in the garage is sound in my opinion, too.

-- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Incidentally, with my unofficial experiment, I had a few smaller lily bulbs that had initially dried like all the rest, but I put them inside a sealed ziplock freezer bag, with all other conditions being the same. They are still nice and firm, but have begun to mold.

Rick, Lots of good interesting information in your post. So much, I don't know where to start. But for the sake of discussion I just want to elaborate on a couple things. First the USDA zone hardiness chart. For readers that may not know, the hardiness zones are based on the average of the lowest temperature each year for a period of years for a given location. Since Anchorage has a maritime influence and somewhat of a micro climate it lowest wintertime temperatures are modified putting it within the same zone range as places like Chicago and Milwaukee. But during the three coldest months of Dec. Jan and Feb, even within the same zone of 5 and 5b, the temperature differences are significant, well maybe not to some, but in terms of climate data, they are substantial. And, one lowest temperature per month doesn't tell us what the other 29 or 30 days were nor how many total hours of real cold temperatures are experienced. To know that we'd have to integrate the entire area under the curve for each city. But to make a point, places like Chicago, Milwaukee, or Des Moines could have just one cold day a month and end up in zone 5 for that year while it's average temperature is/was warmer overall (as compared to Anchorage ). So, there must be a reason gardeners in Des Moines and Chicago can grow beautiful OT's, etc., and then leave the bulbs in the ground year after year, while those in Anchorage can not. And I think it's all about duration of persistent cold and how far down that cold drives the frost level and what the soil temperature at bulb level is and for what duration. What do you think?

Another point about soil temperature, Rick. Once you start taking soil temperatures, you would be in for a real surprise; it's much warmer than you would ever expect, even without a mulch. This good ol' earth contains a lot of heat and that continually and constantly is rising toward the surface. and the farther south you go the warmer the soil is to begin with. I'll bet you a good lunch that your soil temperature at bulb level right now in your zone 4 is still at least 5'F warmer than in zone 5 in Anchorage.

Asiatics? Yeah, their tough. Funny, how we learn by accidental experience sometimes. I once had quite a few extra of Ed McRae's Pixies so I threw them in a Lily Garden shipping box and closed it without covering the bulbs even. I had intended to take them up to the farm the next mornimg, but I forgot 'em. Anyway, while I was gone for a week, my wife put them under a chair on my ponderosa type porch. Out of sight with winter fast approaching, I really forgot about them then---until the next April when I discovered them. We had experienced several days of below zero weather that winter, like 10 below. They were dehydrated and soft, but I did finally take them to the farm and planted them that following Spring. They all lived, albeit a little spindly with only some flowers. But lose Asiatic bulblets left on the surface here all winter will survive just fine if the voles don't find them. Orientals, OT's, Trumpets, would never survive that. So burying pots of those in Anchorage with lots of mulch might work, or maybe not because of the duration thing. I dono. But like we say--there's one way to find out--try it.




Anchorage, D 25/13, J 23,/11, F 27/14.
Chicago: D 36/23, J 32/18, F 34/20.
Milw., D 33/20, J 29/16, F 33/19.

Some interesting reading here using the Sunset Climate Zone maps.

http://www.sunset.com/garden/c...

Unlike the USDA Plant Hardiness Zone maps which is based on only the coldest temperature of a winter, these maps consider many other factors, like micro climates within a particular, much smaller area. This makes things look more favorable for growing lilies in Anchorage than I previously thought, especially in the warm spots. So, burying the pots sideways with good mulch in winter could most likely be done in those areas with pretty good confidence. Not only that, there's a pretty good possibility that lilies could be left in ground year-round in these warmer areas of Anchorage, especially a garden with a southern exposure and southern slope to it. I would also try a slightly raised bed because that would warm faster in early Spring than the regular surface.

Mary, are you familiar with these warmer areas of Anchorage?

I suspect the soil cold duration(and through the summer) has as much to do with ultimate lily performance in the ground just as much as a lower temperature limit. I'm not sold with growing lilies in the ground in areas where soil temps stay very cold, comparatively speaking. Many of us know the trials and tribulations that Darm Crook experiences in the Northwest Territories of Canada, USDA zone 2b. Yet the permafrost maps seem to be about the same for him in Hay River, NWT and Mary in Anchorage, Alaska.

(from Lot 1021 Geotechnical Evaluation EBA 2001.pdf and AlaskaPermafrostMap_Front_Dec2008_Jorgenson_etal_2008.pdf

Coupled with the very very short Alaska summer and despite such long day length, I think lilies will do much much better in pots that warm quickly in the spring. But the data also seems to show that soil temperature micro climates are more drastically diverse than what we are used to farther south. Micro climates like a south facing hill that would absorb more solar radiation, for example. I'm guessing this stems from the the far more drastic differences in seasonal day lengths and the implications thereof.

I got to thinking more about soil temp comparisons with my zone 4. It's generally stated that the depth of foundation footings for heated buildings is 4ft here. I've always thought this was "weird" since it's not that rare for frost to go down 5 or 6 ft. Well I looked it up, and Minnesota code for my area says minimum 42 inches. It can be explained by the principle that the heat from the heated building prevents the soil below it from freezing. This is an illustration of how the physics work in south central Alaska.


And isn't it interesting to note that Anchorage municipality code for residential footings are also 42 inches. www.muni.org/Departments/OCPD/development/BSD/Handouts/handoutrd01.pdf That again, is for a heated building. Recommended foundation footings for unheated structures is 10ft!

Well, we kinda geeked out here, Lorn and I, and although we find this quite energizing we hope that not too many of you all became bored.

So a summary is in order:

Cold hardy plants (including lilies) always have some kind of anti-freeze mechanism(s) to deal with below freezing temperatures so that they themselves are not harmed. But to what degree of cold hardiness is the question, and this can vary greatly between species and even between kinds of lilies. In addition, the degree of cold hardiness depends on the phase of growth a lily is in:

In the summer, a growing lily will have almost no freezing temperature tolerance, but as fall progresses (and even into winter), anti-freezing mechanisms build in the plant and increase as colder and colder temps approach. Then as spring arrives (or as the lily thinks spring arrives as it sprouts in Mary’s garage) cold tolerance begins to wain. That’s why you can’t put those sprouting lilies outside. They have lost a lot of the anti-freeze that they had during their winter phase.

The proof is in the pudding, but we both think pots in the ground and mulched well over the winter will be fine in Anchorage. Inside the garage, keeping bulbs barely hydrated is an insurance to help prevent premature sprouting. But as most of us have experienced dry bulbs sprouting In the fridge, it’s not the end all answer. Lack of excess moisture and temperature work together to keep lilies in their most restful winter phase.

MARY -make it easy ..move to lower Australia!

Anthony, you would have to send her a few samples of Vegemite to see if she could take it! Lol

My poor 'osophagus' struggles with 'late night Vegemite delicacies' .. , but I have grown up on it ... 'miss a meal' .. Cook a cheese & vegemite sandwich...

'ozophagus' ?

Need help? Don't use garden soil in pots. You'll learn a valuable lesson from that

Roosterlorn said:
Edit Added: I forgot to mention something very important: Lilies (lilium) of this type do not like wet, soggy soil. These are not water lilies, and, contrary to popular belief--true lilies do not like a lot of water.

I have a water(ing) question--I'm a newbie too and don't really know too much but I do love lilies!

I just planted some and when I watered them in, the water pooled a bit on the surface of the soil. The pooling was completely gone, that is, the water completely soaked through the soil in about 40 seconds. Is the soil holding too much water for lilies? I think I remember reading somewhere that as long as the water soaks in within 5 minutes, it'll be okay, but I'm not sure.

That's perfect, Joanna. Exactly the way you want it.

Roosterlorn said:That's perfect, Joanna. Exactly the way you want it.

Thank you! I was a bit concerned! This is the first time I'm actually planning my little garden out and I'm really excited about it! In the past, I just planted and everything has really suffered for it.

Sooooo, just to confirm something now that summer is almost over and most of the stems are either dead or dying back.

We don't let the soil dry out completely during their "dormancy" right?

I'm surprised most of your stems are either dead or dying back. It's only in the past week or two that some of mine have started to yellow; the vast majority are still quite green.

My understanding is that they don't like to dry out completely, but if you've got them in a garden bed they should be fine. It's only in small pots that they can actually dry out too much, I think. One metric I've read about for checking if they need watering is to push your finger into the soil as far it will go. If dirt sticks to your fingertip, then there's still enough moisture in the soil.

Happy to be corrected by more experienced growers if I've gotten something wrong.

It may have just been the heat wave, it did get to 45C (113F), resulting in the leaves getting fried...many of them are more brown then green presently. I'm just assuming it's the normal die back but I've never seen it before with liliums so it's not like I know if this is normal time for the area or not.

Woah - that heat would make toast of a lot of lilies! I find this phase the trickiest time for watering. Have lost quite a few over the years that became too dry in their pots. If they get too dry the roots die off... then the rain comes and they rot.

Regarding when lilies die back, there is a lot of variation even with the same lilies in the same town; within reason, it's not anything to worry about. The plants are just adapting to a particular garden's conditions and the gardener's cultural habits. For instance, most people's martagons in the south central Minnesota (where I am) die back by the end of August. Mine don't until at least the end of September.

Josh is right, that you shouldn't have to worry about dormant bulbs getting too dry when they are in the ground. But if it is bare ground, you might want to think about covering it with some kind of mulching material so the sun doesn't heat up the soil too much.