With a small suburban garden and over 150+ varieties in our collection I also had to be creative. Since my husband likes the larger varieties and I still enjoy my perennial gardens we have had to elevate and place the 75 containers in interesting spots. Most are elevated and like you Mark we place them in large 15 to 20 gallon containers. Like Wendy we do keep them in a garage in winter. We bring them in just before Christmas and place them side by side. Never stack. Depending on weather they need to thaw slowly because spring rains can create rot if not thawed. I find that the large varieties grow larger. We've been doing this for 10 years with little loss. I have tried tipping some last year and it seems to work. I may do more of that this year because it is a chore to bring those babies in for the winter! Some that I have loss seems to be ones that I planted late in the season. Not sure why that is. But all in all I believe we've only lost 6 in the past 10 years...and they were replaced. If what your doing works keep doing it. The plus is when you have an empty spot in the garden you can just place a nice container in and enjoy it's beauty.

i would doubt the side insulation was necessary .... dormant is dormant ... the top should be baited in case of rodents .. they key ..as with all potted plants ... no matter what plant.. or what pot ... get it dormant.. keep it dormant ... pots can thaw in winter ... especially if left in the sun .. ANYTHING you do .. to insulate from the effects of sun.. or a warm snap.. is positive ... in the cold zones.. get the soil frozen ... the plant dormant.. and KEEP IT FROZEN and the plant frozen.. and you are all set ... iots the repeated back and forth that is the problem ... the 4 footer.. probably un-necessary .. the 12 inch deep pot.. probably a good idea ... as for the top .. there is no reason it need be in contact with the soil.. as long as it deflects any direct sun ... which might avoid the rodent issue ... i am pretty sure.. van wade covers all his pots with fold-able insulating sheets inside his greenhouses ... and loses about 50% [or some ridiculous % he once told me] .. mostly all to the vermin ... ken

I think I would haul them in only if I thought the wood might be infested with termites. Even though redwood is resistant overtime weathered wood can apparently be infested. Those chemicals are ones used in soil fumigation but obviously not the same rate, formulations, etc. Some of these chemicals are being phased out and none of them are available to the homeowner to sterilize their soil. I don't think psyllids have a cycle where they are in the soil anyway (?) and I would not go to all that trouble for ants. Just use boiling water or soap and water. You could dump all the soil on a big tarp, add new compost, etc. and put the redwood containers in to be gassed. I tend to agree with the technician but I am no expert so could not tell you to go ahead and do it. I pour boiling water (VERY CAREFULLY) in containers invested with nematodes --would not be prepared to do what you propose because it seems to be the antithesis of Integrated Pest Management gardening where you go for the least toxic methods first.

It's often listed as hardy to as cold as USDA z4a, but z5a is probably more realistic, so in order to be safe, you should plan ion giving it some protection other than the covered porch with a western exposure. Reason: The porch will get too warm during any warm spells after mid-January when the plant will have moved from its truly dormant state to a state of quiescence (quiet rest). While in this state, the plant is filly capable of growth, but under normal conditions chill would keep it from growing. Warm temps will cause onset of growth too early. Onset of growth eliminates the protection against cold the plant enjoys during dormancy and quiescence and the next cold spell could kill the plant w/o protection against any lows below freezing (32F/ 0C). Roots of most temperate plants are at least somewhat protected against root temperatures below the freezing point. Killing low root temperatures vary from species to species and several other factors related to cultural effects and root cell contents. There are 3 types of water that should be mentioned when discussing cold injury to roots. As long as actual root temperatures do not fall below the killing low temp, water in the soil can freeze solid with little or no ill effects on the roots or plant, other than the windburn that can occur in evergreens when the soil solution is unavailable for uptake because it's locked up as ice. Unbound/ intercellular water (water in between plant cells) can also freeze without damage to the plant unless, during freeze/ thaw cycles, the plant has undergone extended periods of warm temperatures and the resultant loss of protection against cold injury that comes with such exposure. That leaves us with bound/ intracellular water (water inside of cells). As the plant enters dormancy, the amount of water held within each cell is reduced. This increases the the level of dissolved solids/ salts in intracellular water, which lowers the freezing point of said water by the same mechanism that salt applied to icy roads or sidewalks lowers the freezing point of water. It is when this intracellular water freezes that cells, groups of cells (tissue) or the entire organism can lose viability to killing low temperatures. As far as freeze/ thaw cycles are concerned - if the warm temps last only a day or two, no damage is likely to occur, even if there are dozens of instances where the soil solution and intercellular/ unbound water freezes and thaws; however, if temps above about 43-45* last for several days, any freeze/ that cycle subsequent to the onset of growth will almost certainly cause injury or even death of parts or all of the organism. Can you put the plant on the ground against the north wall of a heated building and mulch it with leaves or straw for the winter. You want to keep it out of the sun or where the sun can affect temperatures directly (like the porch you mentioned). You could also bury the pot in any bed or garden (preferably in shade), or over-winter in an unheated garage. Some people over-winter some plants in window wells, but your plant might not get enough chill there to release it from its dormant state. It will be necessary to water the plant every couple of weeks. A shovel full of snow piled on top of the plant works great. I 'water' many of my dormant trees in smaller pots by placing snowballs on top of the soil. Insulating the inside of the pot will not do any good unless you have a plan to capture heat from an extraneous source - wall of a heated building, geothermal heat rising through the soil in your beds/garden or the garage floor, ... Click me for another Chamaecyparis discussion Ins/ outs of insulating containers Al