CactiGuide.com

Yes indeed it's right, Daiv. Double isolated with bubble wrap from inside and outside.
Mainly I do use a propane heater and as backup there is an electrical fan heater.
Temperature inside is between 5 to 8°C (41-46F) at night. On day it's somewhat higher.
The third pic is also a puzzle pic. Where are the hotbeds?

I'll do show you the hotbeds. The plants inside needs light, so I've do remove the snow and opens the windows for fresh air on sunny days.



Let's have a look inside there are some several
Escobaria, Echinocereus and Opuntia


inside the other one some several Cylindropuntia and Opuntia


The lowest temperature inside was -10°C (14F) since December. The plants looks therefor very vital and healthy.

Nice. What you call a "hot bed", I have heard called a "cold frame". Your term makes more sense to me.

How about a look inside the greenhouse?

daiv wrote:Nice. What you call a "hot bed", I have heard called a "cold frame". Your term makes more sense to me.

"Cold frame" aways seemed sort of obtuse to me.

Awesome plants and pictures Ralf! TFS.

A hot bed is different from a cold frame. It is heated (duhh!). Traditionally the heat is provided by a layer of composting material such as manure, in which the plants can then be grown directly. Hence the cold frame is a frame which is not heated.

After all those years, it finally makes sense!

Now Ian, do you know this because at some point you were wondering about this too?

Aha, now I'm a little step more clever, thanks iann.
Now in the following I'll use the term "cold frame".
It's a lot of work to correcting my site.

daiv wrote:How about a look inside the greenhouse?

Sure, of course. But I'll do this in another topic.

@TimN
What do you mean with "TFS"? I'm not really good in your language.

Ralf wrote: What do you mean with "TFS"? I'm not really good in your language.

Short for "Thanks For Sharing".

Very nice! You've got some plants I wish I could grow outside!

Why don't you do it? It's also in pots and bowls possible.

I don't know if this topic is still hot. However, I am a beginner and found a grower in Germany who is specialised on outdoor cacti growing here.
Homepage (in German): http://winter-kaktus.de
I translated the most important facts:
The following cacti can be grown outdoors in Germany (up to -20° Celsius, some of them up to -30° Celsius; 500-700ml rainfall, no rainfall protection):

• Echinocereus triglochidiatus − coccineus group: (monacanthus, gonacanthus); mojavensis, v. inermis; coccineus, v. paucispinus, v. „minor“.
• Echinocereus caespitosus − baileyi group: „reichenbachii“, caespitosus, perbellus, baileyi, v. albis­pinus
• Echinocereus engelmannii − fendleri group: some fendleri-forms and engelmannii v. variegatus
• Echinocereus x-roetteri, x-lloydii group: x-roetteri, x-lloydii, x-rosei, x-guerneyi, x-octacanthus
• Escobaria vivipara group: vivipara, neomexicana, arizonica, kaiba­bensis, radiosa
• Escobaria sneedii − orcuttii group: sneedii, leei, orcuttii, v. königii, v. macraxima, villardii, guadalupensis, sandbergi
• Escobaria missouriensis group: missouriensis, ssp. caespitosa
• Pediocactus simpsonii (note that they might need rain shelter)
• Platyopuntia with big flat branches: engelmannii, phaeacantha, cymochila, compressa, humifusa, erinacea, macrorhiza
• Opuntia fragilis group: most of them
• Cylindropuntia imbricata
• Maihuenia: poeppigii, valentinii, patagonica (note that not all clones are hardy)

I took this information from here: http://winter-kaktus.de/index.php?optio ... Itemid=108
There you can also find some cacti which are less hardy (up to -15° Celsius) at the end of the page.

Note that I did not include the hybrids.

Please excuse me if I didn't write the names properly since I am a beginner and just tried to translate the info from the URL above But maybe someone might find this useful.

I started with a Cylindropuntia imbricata, an Echinocereus cocchineus and some succulents. Let's see if it works...

PixMe - Read up ALL posts & pics of Ralf's -- he's as good as they come with cold-hardy's in Germany!