....do plants in their natural habitats have access to all the nutrients they need...all the time?

They certainly have access to enough of the nutrients they need to grow to the reproductive stage, or they would soon die out. But, I'll bet none of us would be satisfied with an aquarium with plants in the same situation that those plants endure in nature. We, like farmers, want more healthy, better growing plants, with more of them growing well in our tanks. And, we aren't interested in them reproducing naturally, we prune them to keep them the way we like them.

Most systems are highly season, the water level also changes dramatically in most locations, Tropics etc, unless you like dry terrariums.....................

"Need" is quite another matter.

Need for the community or species?
Yes, for the individual plant? Leaf?

Very often not.
See the difference?

Regards,
Tom Barr

Well, now, . . . .

Some of us are quite content to set up aquatic environments that are reasonably close to what would occur in nature. More fish, maybe, but the plants more-or-less do what they want to do, within limits, of course.

Some like to grow pumpkins that require trucks to move; others are more into jack-o-lanterns. Both work.

Bill

Even with your non-CO2 tanks, don't you prune occasionally? My impression is that most stem plants in nature like to lay on the water surface or the substrate, or they grow up out of the water to get CO2 and more light. With low growth rate tanks, don't the plants just take a lot longer to reach the water surface?

In my 29 long the H. polysperma does not grow to the surface. The vals do and I cut off the tops of the leaves. I trim once a month, more or less.

In my shorter (in height) tanks the hygros do grow to the surface and spread out, requiring trimming, again about monthly.

In nature I see masses of stem plants covering the surface of the water in the summer, and dying back in the fall.

I think the amount of light is the main factor in determining the growth of stem plants. As you've noted, they can get their carbon from the atmosphere.

Bill

interesting....yes i do now although i had never really thought of it that way. species -vs- individual plant. some of the philosophies regarding fertilizing are starting to make better sense.

my perception when i posted the thought was that basically, aquatic plants, most of the time, probably get little of the nutrients they need to flourish but do quite well anyways. i think my perception of what a flourishing aquatic plant looked like in the wild is more along the lines of what we allow them to actually look like in an ideal micro environment (aquarium), and not what they actually look like in general.

i started to question the validity of excessive fertilizing regimens -vs- what they naturally need. but as Vaughnn pointed out, its generally a question of obtaining the best possible aesthetic outcome for alot of us.

We should wear overalls and a cloth cap when we work on our aquariums, since we are farmers, after all.

VaughnH,

Some of us have large, highly mechanized aquafarms with lights on timers, automatic water changers, dosers, and fish feeders, scavengers that clean up any algae that crops up, and filters that remove the detritus.

The only remaining manual task is the cleaning of filter media. While doing that we wear button-down Oxford shirts. When showing the farm to guests, we add a sports jacket.

Our main farm-related task now is to develop a strategy that will help us to get some of the taxpayers' money that will be passed out when the new administration takes office. After all, our farms do consume CO2.

No offense is intended to the terrafarmers, who work long hours to grow our food. But that is another story.

Bill

Rough, back of an envelope calculation, if 100 million new planted tanks, all with pressurized CO2 could be set up this year, we could sequester a billion pounds of CO2 per year. That's worth a grant application!