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Re: Seasonal variations in Ludwigia

Tom Barr writes...

>Date: Mon, 28 Dec 1998 08:17:17 -0500 (EST)
>From: ac554 at freenet_carleton.ca (David Whittaker)
>Subject: Seasonal changes in Ludwigia x. repens
>Lately I've been getting slow/poor growth from a few plants,
>especially ludwigia and Alternanthera reineckii. The lower
>leaves die and the green algae sets in. Is this the usual
>nutrient problems or might it be due to a seasonal slowdown?
>Anyone else growing the above who has noticed a change?
>I'm also interested to know if those of you who are using
>calcium chloride, as opposed to calcium carbonate or
>bicarbonate to supply calcium, have run into any problems.
>I'm discontinuing its use for now, but I have yet to devise
>a good method of dissolving powdered dolomite without
>clouding the tank.

>Seasonal variations are not the case IMHO due to the fact I have both
>plants L. x repens and A. reineckii and this has never occurred with
>these plants in several set ups over many years. Plants that exhibit
>these conditions almost always have a nutrient deficiency. Often shows
>up in Hygrophila sp. frist. These are good indicator plants.
>I suppose your water is very soft if your adding Ca++  ? My levels stay
>very stable due to great local water and fequent heavy water changes.
>          thanks
>Tom Barr   AGA

I think that you are correct Tom. Old receipts indicate that I sold
a lot of Ludwigia this time last year. There is one reference which
states, "All of the Ludwigia species have a habit of shedding their
lower leaves at the beginning of the winter period, especially in
a heated tank. Before they fall off, brown necrotic spots appear on
the leaves. This is surely connected with vegetative rhythm." This
is from Windelov's Tropica Catalogue, 1987. I wasn't sure whether
or not to believe this.

However, there is a problem. Is Alternanthera as sensitive to
copper as Ludwigia?

Dave Whittaker
ac554 at FreeNet_Carleton.ca