Growing nerines

Nick de Rothschild
Mon, 03 Oct 2011 11:52:37 PDT
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 plastic....

Nick de Rothschild

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