I was told to age them a year before using concrete for bonsai.
Many bonsai are on the verge of dying by virtue of starving them and adding chemicals from concrete could alter the strict balance and kill them.

I made few tufa pots for cascade juniper and scoop pot for boxwood-plants are doing fine.
Pots were leeched for 7-10 days in a big bucket of water, changed water every day.
A year or so ago saw pic of wonderful concrete fondue scoop pots on Internet bonsai club site.
Some how-to on slabs for forest planting at
www.btinternet.com/~colinlewis.bonsai/Reading/Cement.html
:-)

"Many bonsai are on the verge of dying by virtue of starving them "

That sounds so mean!

From personal experience, hypertufa works quite well for bonsai pots. When using hypertufa, one should not experience any more difficulty with bonsai plants than traditionally cultivated plants, provided the pot has been thoroughly leeched. Most plants have evolved the ability to acclimate themselves to a wide range of resource availability (i.e. space, nutrients, light, etc.) and, in the case of bonsai plants, they are simply doing that. By reducing/constricting the root system, the shoot necessarily corresponds in kind (root to shoot ratio) and, consequently, the nutrient and water are typically carefully regulated to maintain the current plant size rather than encourage excessive new growth. It's really not a case of plant abuse or torture although certainly most bonsai's require regular attention regarding water as they usually have greatly reduced soil volume and, thus, water storage capacity.

I have made some very interesting fake rock formations that nicely accommodate bonsai plantings.

I second everything Andromo..... said. Plants are wonderfully adaptable. Some years ago I harvested some red junipers, to use as bonsai, growing on the side of a high sandstone bluff overlooking the Wisconsin River here. They were stunted and twisted all on their own by virtue of where they took root. They were producing berries even though they were subminiatures of their full size brethren growing on top of the bluff. Thats what plants do, they make the best of their conditions and will do anything to reproduce. As is natures way.

From what I understood from the person I harvested them for, they would actually recieve better care now ensuring a longer life for them. They'd even have their roots cropped as the tops were, to make sure as Andromo said they had that "root to shoot" ratio correct. This was so they were comfortble in their small pots.

Cement is 98-99% cured at 30 days (under good conditions) and again as Androm says there should be no problems if the pot has been well leeched.

This discussion has got me planning a return trip now to harvest some and plant them in MY very own pots. With what I've learned here and other forums I'll even be able to make the pots resemble the yellow sandstone from where they came from.

Rock, I would be interested in knowing what plant species you collect on your upcomming trip. Also, what sizes you target for collection, etc. And, of course, it woud be excellent to see your hypertufa rock formations.

Sorry I was just repeating what Coastal Concepts wrote in another thread read his comments below. I assumed seeing as none of you disagreed with him at the time he was correct. His comments are below.

* Posted by: coastal_concepts Vancouver CA (My Page) on Fri, Nov 4, 05 at 16:55

From my experience, you should be aware that new concrete will harm / kill bonsai plants which are sensitive to acidity / PH balance. Concrete needs an extensive period to cure and stabalize before you introduce plant life.

In general 1 year of sitting outside will be enough for the concrete to stabalize. Another option is to fill the planter with water for 30 days adding a few drops of muriatic acid to the water every 2-3 days. Swimming pool testing supplies will allow you to monitor the acidity, PH balance and total alkalinity of the water in the planter. If you were to fill the planter with clean water and let it sit for 3 days without treatment and then test it, you will notice a leathal (to plant life) surge in the total alkalinity.

My wife (bonzai expert) learned this the hard way using a planter that I had built that poisoned the plants.

Here is a link that might be useful: bonsai and concrete

Andro, The species could have been one of several varieties, as they could all be growing in the same habitat where we found them.

Cedar, Eastern Red Juniperus virginiana
Juniper, Common Juniperus communis
Juniper, Creeping Juniperus horizontalis

My memory of that trip is not crystal clear but it could any of those. I just remember the person say "red juniper".

The sizes were anywhere from 8" to 18". This person was a Bonsai professional and was greatly impressed by the natural growing conditions that produced the stunted and twisted plants. She said it would take very little to "train" them LOL.

I don't know an awful lot about Bonsai but now I think it would the time to learn more about this. :-))

The shapes and colors of the pots would resemble the Wisconsin Dells area. It's world famous for the rock formations found there. A Google image search would give you an idea of what I'd be shooting for.

I only hope I come close in imitating them.

Here is a link that might be useful: Wisconsin Trees

There is a general misconception that somehow bonsai plants are physiologically quite different than non-bonsai plants. Indeed, some plant species/genera are quite sensitive to varying pH levels but this is not because they are grown in small containers. Not all species would thrive well in a hypertufa container regardless of the container size.

David, There was nothing to disagree about at the time. He was speaking from his personal experience. I'm sure all of us have experienced a plant die on us even though it got the best of care.

His description of putting the water in the pot and adding acid to neutralize the PH was spot on too.

I've also seen in this forum where others have said that they've had no problems planting after the 30 day curing. So it's six of one thing and a half dozen of the other thing, take your choice.

I would like to make hypertufa troughs for planting miniature hostas. Do you need to leech any pot before using it for growing plants?
Thank you.
Jakki

Jakki, It can't hurt to leach and it only takes a couple of days. I make bonsai planters and full size troughs/pots from hypertufa, unmold in 24 hours, GENTLY wire brush the outside walls and top edge, rinse with water and place in a tub full of water to finish curing and to leach out the water. Small bonsai containers can have the lime leached out in 2 days. A full size trough takes about 3 days. You're only talking about 4 or 5 days from the start of making the containers. There is information in the FAQ section at the top of the page for the Hypertufa forum. You can also do a search for this information. Billie

Could someone explain the leeching process in more detail, or point me to someplace where I could read about it?

Thanks!

What I have found with the cement trays, pots, and containers I have made is that a curing period is extremely important. However, even more important is to seal the cement to prevent leeching and loss of moisture. Thompson's water seal, which I have also used to preserve wood trays, has worked well. Just make sure you wipe off the excess seal and let the seal dry for a few days.