Pottery intended for food typically uses glazes without lead or other contaminants. I have read that inexpensive pots (these were!) are fired at low temperatures which require special low temperature glaze which may contain lead or other heavy metals. There was a scare a few years ago about cookware from outside the USA using lead glaze. I don't know what's in the Malaysian glaze but since the pots are for plants there's unlikely any control. The pot interiors are permeable (I tested with a few drops of water which soaked in) so I am concerned if water can reach the exterior glaze from inside that there may be long-term transfer of lead or cadmium (which I don't know is _not_ there) or whatever to the inside. Plastic liner pots is a good idea but it's hard to find ones to fit the containers without dropping in size so much I am losing 1/4-1/3 the volume of the container. I'll hunt around since you are right, it does make them much lighter to move if it can be done as two pieces, but this isn't exactly the best time of year to go hunting for pots in Minnesota! I bought water-based acrylic finish and painted on 2 layers. I did this to all the pots so they are generally sealed against water soaking into the pottery (I could end up storing empty pots outside in freezing temperatures). For one of the fruit trees I also lined the pot with a piece of old shower curtain so there's now 3 layers between the plant and the pot. At least the plant is happy now and if I can find a plastic liner pot that fits I can transfer it later.

Have you tried posting this on the container gardening forum? I'd say that selecting appropriate pots or cotainers is the least of your worries, as your winter cold will put pretty much everything at risk. FWIW, plants suited to long term container growth should be selected based on hardiness of at least one full zone (preferrably 2) colder than your regular climate, as that is the effect they will have to endure in a containered situation. That limites your choices to plants with a hardiness of zone 4 temperatures, better with zone 3. Size will have a significant bearing as well - the larger the container, the less likely the soil in it will freeze solid in winter. As for containers, wood will withstand winter cold better than any ceramic pot, but there is a large selection of frostpruf glazed pots originating in Asia that are totally winterproof, at least in my climate. Concrete aggregate should winterize well also but is heavy and very expensive and typically only available to the trade, as they are primarily used in commercial settings. Avoid terra cotta and plastic as neither will withstand freezes for long (terra cotta spalls and plastic cracks). A good quality potting soil - never regular garden soil - should be used, as garden soil is too heavy and doesn't have sufficient drainage. For long term container growth of trees and shrubs, I use a potting soil recommended specifically for them, as their needs are different than those of annuals or perennials or other, faster to mature plants. Adding some coarse, barky compost to regular potting soil will work if your choices of specific potting soils is limited. And always include some slow release fertilizer at time of planting. You will needs to supplement this as time goes by, as the watering requirements for plants in containers will leach any nutrients rapidly out of the soil and they will need to be replaced.

Kathy, if the pot is glazed inside and out, it should not crack. What makes them crack (terra cotta especially) is that they are porous. It rains (or you water the plant), the pot gets wet and soaks up the water. The water freezes, expands and cracks the pot. If it's glazed, the water should not be able to enter the pot. So, it should not crack if it's fully glazed. If you have any pots are unglazed or that have unglazed areas, just spray them with Thompson's water seal each fall when they are dry and they usually won't crack. Yes, ken I understand there is a big difference in a 9f freeze overnight and a -9 degree week. I understand also that we in the Southern states are total wimps about freezing weather. However, technically, if it's 32f or lower for an extended period of time, it's a freeze. A frost is mid-thirties with a short period below 32f. That is according to NOAA. I also understand they didn't consult with you before issuing their definitions, so you're just going to have to straighten them out. Kathy, I know this doesn't seem logical, but in 2013, almost all the hosta I lost was 2 or 3 feet off the ground. The hosta that were just slightly off the ground, as on pot feet or on a bottom shelf fared much better. bk

I see pips! All 3 made it. They are about an inch high. More advanced than any of my hostas planted outside. ==>>> congrats .... but it shows.. that the garage is trapping and retaining heat on sunny days ... and that is why they are ahead of the outside ones ... too many peeps think its about how warm it is during the day ... but its not.. its about how cold it is at night ... the real show starts.. when nights start getting warmer.. in your garden .... outside.. the ground loses whatever daytime heat is generated.. but the media in the garage ... retains the heat longer into the night ... sooo ... they will need to be hardened off to outdoor night time temps.. including protecting from any frost freeze event ... so dont get all jazzed.. and just whip them outside ... be patient ... and do harden them off to any direct sun ... when you do it ... last thought .. you need to make sure there is moisture in all the soil ... but you dont want it sodden ... your use of snow was brilliant ... but you can accomplish the same now.. to remoisten the soil.. by using some ice cubes ... which will give you the ability to add water without drenching the whole pot ... and so what.. if it cools the soil a bit ... congrats again .. but without pix.. im not sure its real ... lol ... ken