In message
Jeff Layman wrote:

On 12/06/16 18:01, Michael Bell wrote:
I am growing alder seedlings in 5" pots at 30°C under continuous light
in the hope that they will produce catkins and cones this year for
cross-breeding next year. This is reported to work for birches, a
closely related species, grown naturally it would take 7 years to get
catkins and cones and they would be head-height. The seedlings are now
30" high.

I water daily.

3 of the seedlings have died, there is no obvious reason why, the
earth doesn't smell obviously oxygen-deficient, and another seedling
seems to be going the same way - the leaves are floppy but still green
and not obviously "dried out". When I put the water on them, it
doesn't flow through. They seem to be "ponded". (Is that a word?)

So, I look at the soil I put them in. It seems to be mostly "soil",
should I re-pot my sickly seedling (and others, if that works) with "J
Arthur Bower's General Purpose Compost" or with "Potting Compost" from
my local garden shop?

Or any other thoughts?


Several thoughts...

Could the compost have been contaminated with something like
aminopyralid, or other persistent herbicide?. But those usually cause
leaf curling rather than floppy leaves. And I would have expected more
than 3 or 4 to have shown damage.

Is it possible that the dead trees had their roots eaten (something
similar to vine weevil? I have no idea whether or not vine weevil eats
alder tree roots).

But I do wonder why you are watering daily. Do the pots really dry out
within 24 hours?

Are you perhaps exhausting the plants by forcing them to grow under
unnatural conditions?

You can, of course, try changing the compost as that is pretty easy to
do. What did you use originally? I would try John Innes 2 or 3, rather
than a soilless compost, in any case.

I have come to believe that I have been watering too often. I'll try
watering them every 2 days and judging by the weight of the pots.

Michael





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