[GrampsGrunge]

Aponogeton Ulvaceus Plant Care Sheet - Everything Aquatic

This website explains 'most' of the Ulvaceus hybrids needs for a dormant period, I seem to recall you can pull the bulb out and keep it at low light in a cool water tank for a couple months.

IIRC A. Crispus from Sri-Lanka doesn't have a definite need for dormancy periods, at least my experience was they tended to just grow slower for a few months.

 

[malANDmatt]

What is cool water? Like keep it in the fridge or what? Or room air temp?

 

[GrampsGrunge]

What is cool water? Like keep it in the fridge or what? Or room air temp?

I would think tropical waters cool season. Could be close to 67~70 degrees, depending on the altitude of the stream or lake. I think that refrigerator temperatures would be considered cold, not cool.