I agree that a heater is more important than a filter.
One of the nicer things about a (heavily) planted tank (besides they look nice): plants remove ammonia faster than cycling bacteria.
Some circulation is probably a good thing, even in a planted tank. There will be some cycling bacteria operating; they should be exposed to as much ammonia as may be left after the plants have eaten what they can.
"And regular water changes. With De Chlorinated water." Check