Glossary - Growing plants
Capillary bed:
A bed, usually of
gravel, for germinating punnets of seeds. Water is
fed in continuously from the bottom and kept at a
constant level. Heating may be provided. Replaces
overhead watering which can lead to damping off (a
fungal disease) or can disturb the surface of the
seed mix.
Clone:
Plants which have been
propagated from cuttings or by layering (i.e.
vegetatively) have an identical genetic make-up to
parent plant. They are called clones.
Cotyledon:
A leaf-forming part of
the embryo of a seed plant. Monocotyledons have one
and dicotyledons have two cotyledons in each seed.
Damping off:
A fungal disease which
attacks young seedlings at ground level causing them
to rot and fall over. Overcrowding of seedlings and
poor drainage of seed mix are common causes. Destroy
seedlings as soon as detected.
Hardening off:
The gradual process of
conditioning plants to the garden climate. A shaded
area or a shady, wind-protected position in the
garden is used to acclimatise the young plants for a
week or two, then a further three days of exposed
hardening off is recommended prior to planting out.
Hormone:
A substance which can
be transported through an organism and can affect
growth, reproduction or metabolism (rate at which
food is converted into part of the living thing).
Certain synthetic hormones can be applied to cuttings
to encourage quick root formation. They are
particularly useful for slow rooting species.
Hormones must be used with great care.
Layering:
A method of vegetative
propagation where stems are partially cut and either
wrapped in coconut fibber or pegged down under soil
until they root. Rooted pieces are then cut from the
parent plant and potted up.
Parent plant:
Plant from which
cutting material for propagation is collected.
Peat:
Brown decomposed plant
matter found in some swampy areas. It has a high
water holding capacity and was once widely used in
potting mixes and cutting mixes. The extraction of
peat is having a damaging effect on the ecosystems
from which it is taken and its use is not recommended
for this reason. It is now frequently replaced by
substitutes such as composted woodchips fines,
coconut fibbers or rice hulls.
Potting on:
pH is is the process
of transferring rooted cuttings from the cutting mix
into pots of potting mix for growth before hardening
off. Potting on enables the plant to establish a good
root system.
Pre-treatment:
One method of
pre-treatment involves lightly damaging the seed coat
to allow water uptake necessary for germination.
Usually heat or abrasion (rubbing the seed coat with
sandpaper) are used - e.g. with Acacia seeds.
Pre-treatment for seeds of some plants involves
chilling seeds (cold, moist stratification).
Pricking out:
The process of
transferring seedlings from the seed mix into pots of
potting mix for growth before hardening off and
planting out.
Semi-hardwood:
Last season's growth
which has hardened off. This growth is ready for
preparing cuttings if it does not break when bent in
half.
Sphagnum moss:
A type of moss which
retains moisture well and is sometimes used in
propagation such as in aerial layering. Its use is
not recommended, as serious damage is caused during
its extraction from the fragile areas in which it
grows.
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