Raising Tomato Plants from Seed By Philip Swindells
When reading this, do remember that the author is writing
for an international audience and in the UK growing tomatoes
outdoors is always chancy. Late unexpected frosts, a
cool summer and blight can all take their toll.
Still, getting the plants off to a good start is the
first step to a successful crop of tomatoes.
Tomatoes, although technically short-lived perennials,
are
treated as annuals and raised from seed each year. They
are
sub-tropical plants that require a consistent temperature
of at
least 13ºC (55ºF) in order to germinate successfully,
but a
temperature of 21ºC (70ºF) will produce much
quicker emergence
and is generally preferred. Given warmth, good light
and a damp
friable growing medium tomatoes are very easy to raise
from seed.
For most gardeners, even those that live in warmer districts
where tomatoes are cultivated outdoors from their very
early
stages of growth, it is usual to start the seeds off
in pans or
flats of compost under controlled conditions. Tomatoes
can be
sown directly into the open ground, where the climate
and soil
conditions are suitable, but much better establishment
of better
quality plants always results from controlled seed raising
and
growing the seedlings during their initial stages of
growth in
independent modules or pots. Transplanting is easier
and
establishment is rapid.
As tomato seeds are large enough to handle individually,
it is
best to space them out on the surface of the prepared
compost so
that when they germinate they do not crowd each other.
Also when
they are pricked out there is no undue disturbance of
the
fragile root systems through them having become entangled
with
each other. A properly formulated seed compost is essential.
A
sterile medium of a texture and quality that will offer
the best
start for the germinating seeds.
There are a number of different composts available,
but for the
hobby gardener a good soil-based seed compost is to be
preferred
to a soil-less one. Soil-based composts, although generally
slower to warm-up, and often slightly impairing the speed
of
seed germination, usually yield the finest and strongest
plants,
especially for planting directly into the garden outdoors.
Plants that have been raised in a soil-less compost,
which
almost always comprises a high proportion of friable
peat, often
take time to adapt their roots to the more hostile and
less
forgiving medium of natural garden soil when planted
in their
permanent positions. Sometimes a check in growth occurs
while
the roots adapt, resulting in an impairment in the plant's
development.
Soil-based composts also overcome the problem, commonly
encountered with tomato seedlings raised in a soil-less
medium,
of the seed coat sticking the two seed leaves together,
often
making them inseparable without causing damage. The seed
coat is
generally detached by the coarser soil-based medium as
the
seedlings emerge.
Once the seedlings have their two seed leaves fully
expanded
they should be pricked out, ideally into individual modules
or
small pots, although they can spend two or three weeks
pricked
out into flats in order to save space when this is necessary.
Like all seedlings, tomatoes
that are raised in this manner are
vulnerable to damping off disease. This causes the
seedlings to
rot at the base of the stem and collapse. The routine
use of a
fungicidal treatment is to be recommended.
There's a six part article on growing tomatoes on
this site that may help you as well.
About the author:
Philip Swindells has over 40 years gardening experience. A
former botanical garden curator and an international
horticultural consultant, he has worked extensively in the UK,
North America, the Middle East and Australia. The Author of more
than 50 gardening books, he has been awarded a Quill and Trowel
Award by the Garden Writers' Association of America. He is also
a former UK Garden Writer of the Year.
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