Dave, I can appreciate where you are coming from but I think that there are several things that you need to consider in creating a bog out of an old bathtub or a laundry tub. First off. The plants should be purchased and not collected! Reason why is that nursery grown plants acclimate much more easily than wild collected plants which generally will not survive unless you have had extensive experience in making such transplants. Also you will not need a permit, if you can get one, or permission from landowners to collect. All you need is a link.
Here is one that you might find of interest.
Carnivorous Plants | Carnivorous Plant Nursery
Secondly, you need to keep in mind that a bog is not an enclosure that traps water. A bog is an active biological system through which water migrates and aeration is as important to bog plants as it is to terrestrial plants. So in order to grow bog plants in a tub you will have to have a system that allows for flow-through of water and return/priming of water. For a tub that means either the drain will be covered by a rust proof mesh through which water percolates into a collection basin or the drain is plugged and a collection basin is created in the bottom of the tub by the use of forced air heater filters sitting on a flourescent light egg crate screen that is supported by plastic braces that are tall enough to allow the placement of a water pump that will pump the water out of the basin which is being filled by the return water to which may be added additional water to maintain the water level in the basin with outflow being directed through soaker or spray nozzles. The use of spray nozzles will help maintain localized humidity.
Thirdly, the bog should consist of a deep layer of sphagnum moss or of peat moss. You can buy a large bag or bale of peat moss. Get it soaking wet and
press into the tub to within an inch of the top of the tub. In all cases use only distilled or r/o water.
Once the moss has been packed in let it set for a week and see if there is anything green appearing. If not check out the link above and buy some live sphagnum moss.
Here is a link to my experiences with creating a bog in a tub.
Bog Garden pictures by jwcimage - Photobucket
PLEASE KEEP IN MIND: it is important to weed out any plant that you did not plant into the bog unless you are willing to let the bog go its own way. You may also have to remove plants that you plant into the bog if you are trying to grow a nice stand of sphagnum moss. If so, then I suggest that you only plant one or two other plants only and keep them trimmed to keep them from overgrowing and killing the sphagnum.
Do protect the bog from animals, including pets. I had to dismantle after raccoons literally tore my bog apart looking for something to eat!!!
Bath tub bog
Linear Mode
