It's not about how deep they are that gets them through the winter, it's about them not staying too wet. I don't have to do anything, because my pots don't stay frozen more than a day or two at a time. Where you are the danger is that they stay frozen on the bottom and thaw on the top, which leaves the crown sitting in water.

In regular pots, people in your zone often turn the pots on their sides and put on the north side of a building so they will stay frozen, the sun won't thaw them and water won't stand in them. Some put them on a porch or in a shed. The problem with the shed is that they are effectively in a zone or two warmer than the outdoors, so may come up too early. I've heard of people covering large pots with tarps and boards once they go dormant.

Other than that, the trick to growing in pots is drainage, drainage, drainage.

Maybe someone from your zone will chime in and give you better information.

Good luck.

bk

I have not had great luck overwintering hostas in my hypertufa pots, of which I have many, in different sizes, some are even bottomless in my attempt to ensure good drainage, which is super important in the winter and early spring. Most of my hostas that stay in the tufa pots have survived the winter, but often they are damaged and come back smaller, depending on the severity of the winter. These are pots I just leave out, exposed. The things that come though the winter the best for me ( of my potted ones) are the ones that are completely buried so that the level of the soil in the pot is at the same point as the level of the soil in the ground. So I am guessing that the freeze thaw freeze thaw thing that happens to unburied pots is a big part of why those ones get damaged in my yard. ..that, in combination of not being too wet. Just my opinion! THe ones I bury are just in plastic nursery liners- I do not have the energy to bury anything in a hypertufa pot.

The hypertufa itself does fine over the winter...I don't do anything to protect that.

four of my 5 hypertufa tainers are buried so that the top sticks out at about ground level. you have to keep adding soil every few years. It is a great place for the minis.

I have 1 above ground tufa with a h. white feather in it. It doesn't grow much, but does come back.

I like to mix yogurt and moss in the blender and "paint the tufa" edges with the slurry.

The sides moss up much quicker that way.

dave

^_^ --~

The info in bkay's post is a very good description of what happens and col_123 has found a great way to handle it with her advice.

Are you making the hypertufa pots/troughs yourself? If you are, and haven't begun the project, let's think outside of the box for a moment... try to imagine a way to put "drainage" holes in the upper portion of the pot.

Create the drainage holes on the upper side in the hypertufa to drain that portion and eliminate pooling. Form these drain holes approximately 2-3" from the top and install screening into holes (for drainage) located 2-3" from the top.

The screening will hold back the potting medium and allow drainage. You will still need to make drainage holes in the bottom like normal.

I don't know if it will work, but it would be an interesting experiment with some "expendable" test subjects...
:-)
Deb

Hmmm. Interesting stuff; I'll have to think about it.

I've never had a problem with potted plants thawing at the top, but remaining so frozen at the bottom that nothing drains down the sides.

I definitely will be experimenting with the hypertufa this summer, making containers of different sizes and configurations. We will see! (And you're right, Deb -- expendables first!)

Yes, that's the most important thing- don't plant anything in there that you LOVE and overwinter it, if you'll be crushed when or if it dies or takes damage. You are also a zone warmer than me...in 2011 we had a mild winter and even the unprotected things came through well for me. Last winter was very cold, and I had several casualties. You just never know what kind of winter we will have so I roll the dice with hostas that aren't my favorites.

I had thought that the thicker walls of the hypertufa would be fairly insulating to plants, but in my experience, that has not been true.

There you go. Someone who knows something almost always chimes in. We're lucky about that on this forum.

bk

I agree with the too wet statement. Out of the 12 minis that I bought and planted last year in two large concrete bowls, at least 18" deep - I lost 9!

I won't be doing that again. I have done the same thing as Colleen and that is to sink the black nursery pots in my veggie garden and that has been fine. Soooo you could get a black pot that fits into a hypertufa container and then transfer the hosta to the ground for the winter.

Will definitely be careful!

Maybe I don't have enough experience with hypertufa, but I would have thought that -- given equal drainage -- the hypertufa would breath more than plastic?

Lots to learn!

This post was edited by alison on Thu, Jul 11, 13 at 13:01

I overwintered one in hypertufa but 'no go', but as said above, I am in a colder zone and this was a particularly bad winter.

I did have success with volcanic rock with a couple of minis.

{{gwi:1056129}}

{{gwi:1056131}}

I found the guy that hollows out 4" holes on the internet - it is 'supposed' to be for bonsai.