Hi! Mikesenior, welcome to AMHD :)
Originally Posted by mikesenior
A lot of people have tried it, and it does work, but not for the length of time you require. As “bathtub watering” is only a short term solution.
The reason your only seeing systems that work only up to 3 weeks is because manufacturers of these products don't expect the homeowner to be away from the premises longer than that.
Justcurious55 (jc) revealed several problems with “bathtub watering”:
i have lost a lot of plants to letting them sit in too much water.
the stopper really isn't good enough to completely stop the water from draining out
all the water would seep out befre you could return
Now this is not to say that it can't be done, only that it hasn't been thought out as far as three months.
I have thought of two ways it could be done, 1) with a drip or 2) a wicking system.
If your still interested let me know, but I have a feeling that your pressed for time, and the best solution as jc has stated
would it be easier to have a neighbor or one of their kids water them for you?
or you'll have to take the plants with you.