Temperature and Plant growth?

[staygreen]

I was just wondering what people know about this. I have heard that an undergravel heater is sometimes needed to keep the roots warm so I was wondering how much the temp effects growth.

I have a small hex tank of about 5 gallons and becuase of aesthetic reasons I did not put a heater in. I have some crypts, java moss and some type of lily bulb. They get light form the sun all day and direc light for just a couple of hours...they seem to be doing pretty good sofar.
The temp probably hovers around the mid sixties at the lowest in the water, heating up into the seventies during the day.

So, will the plants grow slower or be less healthy because of the temp?
How important of a factor is it?

[OrionGirl]

IMO, while it depends a lot on the type of plants, in general, a cooler temp than what most fish prefer is better for the plants. As with O2, there is more dissolved CO2 in cooler water than in warmer water. I have similar lights over a 55 and a 40, better substrate in the 55 but more height. The 55 is also much cooler than the 40. Some plants do great in both tanks (crypts, and swords), but the anubias, java moss, and dwarf lilies won't grow in the 40, but are very happy in the cooler water of the 55. Most bunch plants--indica varities, moneywort, and ludwigia varieties--do much better in the 40. Of course, there are other difference between the setups, but I do think the lower temp of the 55 contributes to those particular plants doing well.

[staygreen]

WOW!eek:

-Girl I thought it would be exactly the opposite! I was thinking that colder water would be detrimental to these plants...

Around what is the temp difference in your tank?:

[OrionGirl]

The cool tank stays around 68-72, the 40 is at 78 all the time.

I think part of the problem is that most of the aquatic plants we have access to are not true tropical plants. Many tropical waters have very little in the way of vegetation--and lots of what is there is HUGE, not appropriate to small tanks. So, we end up with plants that are not actually native to true tropics, but are hardy enough to withstand them. There are exceptions of course, but I think cooler planted tanks do better than warmer ones.