War. War never changes.
Peat is justa LOT of organic material, so you can use it for a thousand and one things. It's not good horticultural practice to reuse media. If it's too old for one plant, then it's too only for the other. However, there are caveats.
If the media just got waterlogged and is having trouble with anarobic bacteria, then you can remove the plant and presumably treat the substrate and have it be useable again.
Media that you're getting rid of simply because it's old is no longer useful for your CPs, but there are a thousand and one uses for it otherwise. Since peat is just organic material it can be very useful for the garden whether to supplement a particularly sandy or clay laden soil for general garden health or you can simply compost the material and "go with the flow."
Peat is versatile, whatever state it's in and I can't see any good reason to ever throw it away (though I'm sure someone could come up with some...)
Well the thing with bog bowls is that they have like 100 times more peat than one pot and about 10 times the amount of plants so I will definitely not consider it to be an EASY job. I just prefer to be prepared as possible, ok?
I guess I should be able to find some use for the peat outside. None come to mind at the moment though.
Put a pipe under the media as close to the bottom as you can get, so you can drain that old water out without disturbing your setup. Run a piece of one inch pipe and let it stick out so you can put a tube down inside to siphon the old water out. If it is going to rain let the rain soak through to wet the mix. This adds new fresh water to flush out any built up minerals. This is how I have my outdoor 4 foot by 8 foot bog garden setup. It works very well and is very useful.
After the 5th read through I understood what you meant. I'm not sure it will be necessary since I do have that little plug on the bottom that I can open to drain the water. My bog actually dries out quite often so there isn't always water sitting in it. After a while the peat pulls away from the side and gets a bit spongy, but it stays moist.
War. War never changes.
Frankly, if there's so much media, it's almost a waste. Nothing really needs THAT much root space. I've got some Neps and Sarrs with pretty extensive root systems, some even have roots growing out the bottom by a good bit, but they still grow fine.
I'd say save yourself the trouble and use a more shallow container. Maybe I'm misreading here, but it sounds like theres a lot more media than there needs to be. Too much media leads to problems like the ones you've mentioned (having to deal with all of the extra media,) compaction, a greater potential to let anarobic bacteria take over, etc.
I can't think of a good reason to have a large amount of excess media. You need some room for the roots to grow in to, granted, but going overboard leads to annoyances.
Well I squeezed as many plants in there as possible.. and actually the reason I made the bog bowl in the first place was to keep the media from freezing solid in the winter.. that's the reason that my sarrs and VFTs keep dying every winter. So I figured that a bog bowl would keep the rhizomes and roots more protected. I'm not sure how effective it will be, but I am also going to build a cold frame for it as well, but with the cold frame I wouldn't need the bog bowl in the first place... so yeah the bog bowl is probably only going to be a temporary thing. After a year or so I will take it apart... it wastes too much water as well.. when we go a week without rain I have to pour in a gallon of distilled water to keep it nice and moist. I do like the way it looks right now though. Looks so.. natural.
Here's a list of the plants in it...
S. jonesii (or S. alabamensis)
S. 'Dixie Lace'
S. 'Judith Finn'
S. 'Scarlette Belle'
VFT 'Big Vigorous'
VFT 'Akai Ryu'
I made sure there was enough room for the sarrs to get fullly grown and I really think I made the best use of the space that I have... I actually kinda feel like I overdid it a bit.