Date: Sat, 15 May 1999 01:18:18 -0400 From: "Mark Pogany" <markp@en.com> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1754$foo@default> Subject: Blackening Drosera tips
Chris wrote-
On the subject of D. Binata and D. Filliformis having black leaf
tips, I live on the outskirts of Montral, Canada. I grow both
species in milled Peat moss, with living peat moss spread on top.
The leaves of both species start out nicely enough when they are
developping, but once they are fully grown, that's when they
usually turn black. I always keep them in a terrarium of some
sort. When I put the plants outside they do tend to get direct
sunlight for a about 3 or 4 hours, so I thought it might have been
a heat build up, but the same thing happens inside when grown on a
windowsill or under 2 fluorescent tubes.
Hmmm.. I've never noticed this with any of my filiformis plants but have
with some binatas over the past three years. I guess it might depend on what
strain of D. binata you have growing. This widespread complex grows in
tropical and warm temperate areas, some having dormancy while others don't.
Your plants may be experiencing some kind of modified dormancy which may
explain the same results in growing them in a terrarium and outside. My
clump of binata var. mutifidas (which started out back in late "96 as plain
sp. binata binata) hang from a basket in my greenhouse, about a foot below
the plastic composite roofing that gives diffused sunlight for a few hours a
day. The humidity in there varies from 40% to 75%. I use 60/40 peat-sharp
silica and water when the top of the medium starts to dry a bit. The excess
water runs out the bottom of the container so the binatas roots get about
the same damp to SLIGHTLY dry treatment my Nepenthes get. The times I
usually notice blackened leaf tips is when the plants are going into
dormancy or coming out of same. In my experience the plants I have do not
need ultra high humidity to maintain full healthy lamina during the summer
growing season. Some volunteers even pop up in my Sarracenia pots growing
out in the pachysandra beds. These do die down to the roots below the moss
in fall and come back each spring , after the pots have been turned into
iceblocks for 4 months. The lamina on these do not have black tips even on a
dry, low humidity summer day- just as long as the medium is kept moist.
Mark Pogany
Cleveland, Ohio ( .30 precip in the past few weeks- send rain!)
markp@en.com
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