On 31/08/2019 11:32, Stewart Robert Hinsley wrote:
On 31/08/2019 09:49, Broadback wrote:
Â*From the garden point of view? When I was young, a long time ago, it
started on the 21st Of September. Now the weather men talk of
Meteorological commencing the 1st of September. I have seeds which
require to be sown in the Autumn. When is the best time for this please?

Seasonal sowing of seed is +/- a month or so.

Very few seeds are so timing critical apart from those which must be
sown immediately that they are ready to leave the pod. Some may have
requirements to trigger germination like fire, smoke. heat or cold.

Astronomical autumn starts on the equinox (21 September, more or less).
Meteorological autumn starts on the 1st September. The Wikipedia article
gives some other alternatives - 1st August, 7th August, first Monday of
September.

I think of the first two or three weeks of September as transitional
from summer to autumn - in some years they are summery (an Indian
Summer); in other years they are autumnal.

This year I already have some thermally sensitive plants (including
acer, fig, ginko and lilies) showing signs of autumn colour. I don't
understand how since there has not been a cold enough night to my
knowledge. More usually they do this in mid-september.

The other end of autumn is also variable - in 2009 winter arrived at the
start of November, but in many years it extends well into December.

The best time would depend on the species, the area, and the weather,
but in the absence of data October seems a good compromise.


--
Regards,
Martin Brown