Re: Vermiculite, "lawn" plants, plant ID?

> >To: Aquatic-Plants at actwin_com >Subject: Vermiculite >From:
> Stephen.Pushak at hcsd_hac.com (Stephen Pushak) >Date: Mon, 29 May 95
> 11:21:40 PDT > >Does vermiculite have any useful properties for plant
> substrates? >Has anybody analyzed it's properties? Why do we put it
> in our >house plant pots? 
> Jim Kelly posted an article on sci.aquaria a while ago, with the
> title "Build a Better Substrate". It is about 500 lines long, so I
> will not quote it here. I believe Erik has archived it on the Krib.
> If you can't find it, let me know, and I'll email it to you. 
> Jim's article pointed out that the Cation Exchange Capacity (CEC) of
> Vermiculite was quite high. This means that Vermiculite is very good
> at making metal ions and NH4+ available for uptake by plants.
I used Jim Kelly's method in a tank that I set up about four months ago. I
still can't believe the results I am getting. I have had aquaria on and off
for the last 25 years, but was barely past the keeping plants alive for six
weeks level. Now I am pruning on a weekly basis and the tank looks like the
ones in the books.

>The problem of course, is that it is hard to make Vermiculite >sink.

I solved this problem by soaking the vermiculite for three days in a bucket
of water. I held it down by nesting a second bucket with some rocks in it
inside the first. Kelly's method calls for mashing the vermiclite into a
paste and mixing it with loam soil. It won't float if you do a thorough job.
A paint mixer in an electric drill helped with the mashing the vermiculite
part, but squeezing it through your fingers (after it's been soaked) works
well, too. Drying and screening the soil makes mixing easier. I also mixed in
a small box of Dupla laterite that I already had on hand. Other than that, I
followed his recomendations. I can e-mail the article to those who can't find

While I'm here, my $.02 on the past lawn plant discussion. I like Hydrocotyle
vulgarus, or Pennywort. It grows about 5 cm tall, with a single stem and
leaf, very much like an umbrella. The leaves look a lot like nasturtiums. It
propagates by runners, but not so fast that it gets out of control (so far).
I collected mine while on a visit to Florida. It is quite common there,
growing emersed along the edges of ponds and canals.
I also collected a plant there that I have yet to identify. Round, slightly
pointed leaves grow in opposite pairs. New growth is a  cream color,
darkening to green. Undersides of leaves are reddish. Ludwigia mullertii? I
found it emersed, rooted in water. It grows very well in the aquarium, but
the stems tend to decay over time. I periodically replant the tops. That's a
pain, but it is an attractive plant. Any suggestions?