Steve:

Roger makes a very good point: if you can leverage the ground temperature by wintering your trees under a bench, it is an excellent solution.

The idea of wintering via a cold shed was broached by Yoshimura in his landmark book, The Art of Growing and Caring for Miniature Trees. I winter my Japanese White Pines in the shed because extreme cold is not a problem, and I have grown weary of crawling under benches to check trees. );-)

To mitigate the effects of the cold air rushing beneath the shed and chilling the floor boards, I do the following;

1. Lay out sheets of foam board onto the floor boards in the shed. They are easily and inexpensively acquired from Home Depot.
2. Dump bags of dry cedar mulch onto the foam. This is usually 5 inches deep.
3. The bonsai are placed on the mulch.
4. The trees are drenched.
5. The root pads are covered with heavy black landscape fabric.
6. A chopstick is inserted through the fabric and into the root pad.
7. The pots are covered with cedar mulch--approximately 6-8 inches.

The shed is opened when the temperatures move into the mid 30s F. Once the temperatures drop and we enter a sustained winter freeze, nothing is done to the Japanese White Pines until the spring.

I also use this method for storing my Junipers. I do not recommend this approach for potted Buxus, Acer, Prunus, Ulmus, etc.

Cordially,

Michael

-----Original Message-----
From: Roger Snipes
To:
Sent: Mon, 24 Oct 2005 19:49:45 -0700
Subject: [IBC] Non organic Yamadori soil


Steve,

I'm sure Michael will respond as to which he was recommending.

I would like to comment on your question, though:

As you said the co-poly would warm the mulch during the day but the shed or garage would provide some insulation from the cold ground.

It isn't the cold ground that your trees need protection from, it is the cold air. The ground stays at a relatively even temperature, which is quite a bit warmer than the air temperature, especially as one goes below the surface a bit. Putting your trees on the ground and mulching around them helps to connect them with the ground and keep their rootballs at ground temperature. Roots are designed to live at ground temperature, not at the much colder and widely fluctuating air temperature.

Regards,
Roger Snipes
Spokane, WA. Zone 5-ish
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************************************************** ******************************
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+++++ Questions? Help? e-mail +++++