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3,297 Posts
Discussion Starter · #1 ·
I define plant growth rate by change that is noticeable;

fast - from day to day
medium - from week to week
slow - from month to month
seasonal - varies by season or other long cycle

I consider a centimeter of stem lengthening, or
a centimeter of leaf expansion to be "noticeable".
of course, that measurement should be relative to
how tiny or massive a plant normally grows to be.

of course plant growth rates are relative to how happy
any said plant is with your tank conditions, so a medium
plant for me, could be a fast plant for you, etc.

I was just curious how others benchmark their growth rates, and if
you need to articulate more rates, such as very fast, medium slow, etc.

I wonder how PlantFinder on APC defines their growth rates.

13,609 Posts
A better method that's cheap:

Take a wet weight comparision.
Take one stem plants, add it to salad spinner for 45 sec to remove excess water.

Take the weight

Add plant to the tank and remove very carefully and add to the spinner again for 45 sec and record the weight.

Not perfect but not bad either.

Next, measure the before and after shoot length, leaf no# and size.
Same with the roots.

Fairly simple easy methods.

If you can get a dry weight correlation between wet and dry weight, that would be even better.

You will also want to use about 10 stem plant shoots for each test run.

Tom Barr
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