Growing nerines

Mon, 03 Oct 2011 13:33:09 PDT
It is with great pleasure to read Nick's letter on this subject. I agree
fully with his findings. I have never grown nerines (of any species) in clay
pots) but I have grown other bulbs and cacti in them. That ended about two
years ago after I saw the roots all circling the clay surface, thereby
limiting their search for moisture and nutrients to a small fraction of the
potting mix volume .

What finally decided me to dump clay pots was the difficulty in repotting.
So, one final act of clay unpotting was followed by piling up the old clay
pots. With cacti, the nature of their roots makes them inextricable from the
porous clay surface without serious root damage during extrication. Their
rootlets penetrate into the clay walls in search of water.

Modifying the potting mix to have a slightly more open (aerated) character
in plastic containers than in clay pots is all that I found necessary. I
still have those piles of clay pots! Perhaps I'll find a use for them.

San Diego

-----Original Message-----
From: []
On Behalf Of Nick de Rothschild (by way of Mary Sue
Sent: Monday, October 03, 2011 11:53 AM
Subject: [pbs] Growing nerines

Hope this finds its way onto the forum:

For those of you that grow nerine sarniensis here is an observation- (and we
knows what we are talking about!)

We frequently make a comparison between bulbs grown in clay pots and bulbs
grown in plastic pots and can now make a definitive statement:

The bulbs in clay pots shrink by to 30% of their pre-flowering size whilst
the bulbs grown in plastic pots continue to hold their full pre-flowering
size - you know how the bulb swells in August-September (and if your bulbs
don't swell in September then you are doing something wrong (if you are in
the Northern Hemisphere of course). We also note that seedling bulbs can be
kept in stasis in small plastic seed trays for many years without adverse
effect, other than the bulb size stays small, and only when repotted (we
have some bulbs in this growing scenario that are 8 years old) do the bulbs
then get up to a decent size and the tiny bulbs, like bonsais, produce
diminutive flower heads- we had a collection of the Zinkowski nerines that
were tiny bulbs to start with and they had tiny flowers, and I thought that
they were poor, however given the Exbury Regime, they are now reaching their
full potential as they should be.

Of course, you might say, that other factors are involved... so I can also
say that the ones in clay and the others in the sample that I measured
against were potted up in the same year.  We also split the pots and examine
the roots and notice substantial differences in root growth patterns between
clay and plastic.  In clay the bulbs put a out much greater mass of fibrous
roots that cling to the clay surface, whereas in plastic they are more
evenly spread and not in such abundance.  We surmise, therefore, that the
bulb is losing mass to this root growth, which is deleterious to flowering.
With our potting mix of 5 parts John Innes No 3, 1 part course grit, 1 part
sand, 1 part bulb fibre, 1 part rotten manure, we are achieving 95%
flowering in all our 2 litre show pots. We feed with a 20-20-20 fertiliser
in a weak dilution from now until March.

This year the Exbury Nerine Collection (see
<> for varieties etc)  has flowered
about 3 weeks earlier than usual- This we attribute to a really dull August
when the weather here in the southern UK was miserable (please don't feel
sorry for me I went to Zanzibar instead) however it was noted that there was
almost autumnal temperature fluctuations with very cool nights. This, we
believe, triggered the flower spikes to start growing, and once this happens
they do not stop even if the temperatures then rise again..

Now we have just had a heat wave with record 30 degrees at the start of Oct.
and quite a few are wilting faster.  We keep a 50% shade over them for most
of the year.

So my message to all you n. saniensis growers is- ditch your clay and go

Nick de Rothschild

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