Seed Guide 2007 pgs 01/41 - McKenzie Seeds

G R O W I N G I N F O R M A T I O N
Hardening Off
Half-hardy annuals, half-hardy perennials
and some vegetable seeds have to be
germinated indoors because they would
be damaged by frost, harsh winds or cool
growing conditions.
They are sown early in the year in a
heated greenhouse, propagator, warm
room or even, to start off, in the airing
cupboard. Most seeds need a minimum
temperature of 65F (18C) and will
tolerate a drop overnight to about 50F
(10C), but there are exceptions and they
are dealt with separately.
Once the seedlings emerge they must be
given plenty of light, although not direct
sunlight, until they are large enough to
be transplanted into trays (see page 13).
The final operation before planting out is
to harden off the young plants. The ideal
is gradually to acclimatize the seedlings
to the harsher conditions of the great
outdoors. Allow a minimum of ten days
to do this, and preferably longer.
14
Start by putting the trays in a sheltered
position outdoors for two hours during
daylight and lowering the temperature
of the greenhouse or propagator for the
rest of the day. Slowly increase the period
that the plants are outside so that by the
time the frosts are finished, the plants
are fully conditioned to being outside.
Don't forget that the trays will need
watering but should be protected from
heavy rain.
When the young plants are transplanted
to their flowering positions they may still
need some protection against the
damaging effects of strong, cold winds.
A very useful aid to successful hardening
off is a cold frame. It should be large
enough to accommodate all the seed
trays, but can be a very simple
inexpensive structure. During the day the
lights - that's the glass or plastic cover
over the walls of the frame - can be
opened or removed altogether, but put
back into position overnight.
NIGHT - PROTECT INDOORS DAY - SHELTERED OUTDOORS