GROWING
PLANTS FROM SEED
MARCH – APRIL
To germinate,
seeds need a container, a growing medium, water, sufficient warmth and light.
1)
Any sort of container that allows water to drain will work well. I use old
margarine containers or yoghourt pots with holes pierced in the bottom. I start
seeds that grow large quickly (and so resent transplanting) in 2x2” seed trays
or small pots. This saves a lot of work downstream, but means that they must be
sown in a potting mix which contains more nutrients.
2)
Growing mediums should preferably be nutrient-free: if seedlings are to be
transplanted, start the seeds in a purchased seeding rather than potting mix.
You can make your own seeding mix:
a.
from equal parts of vermiculite or
perlite and sphagnum moss
b.
using third parts of sterilized garden
soil, coarse builder’s sand and peat moss.
Add small
amounts of ground limestone and bone meal to each mix.
3)
Tamp down the seeding mix gently, then water prior to sowing seeds: allow to
drain well. Cover the seed container with plastic or cling wrap to conserve
moisture and warmth.
4)
Warmth required should be indicated on the seed packet: many seeds can be
started on your windowsill, with the exception of those which require high
starting temperatures e.g. marigolds, zinnias and other annuals.
5)
Light required for germination is quite low – a windowsill is fine, as long as
the seeds do not get roasted by direct sunlight. As a rule of thumb, small seeds
(e.g. petunia) should be left uncovered, while larger seeds should be planted
about ¼” deep. Some seeds such as sweet peas must be kept in the dark until
germination has occurred. This should be indicated on the seed packet.
APRIL –
After germination,
seedlings will need more food and reasonable light but less warmth.
1)
If growing in seeding mix, feed with liquid fertilizer twice a week for three
weeks, AFTER the first three true leaves have appeared (the first two small
leaves are not true leaves). Transplant to a potting mix as soon as you can
handle the seedlings.
2)
After transplanting, do not place the seedlings under lights for 24 hours – they
need time to recover from the shock.
3)
If growing in potting mix, feed with liquid fertilizer at full strength every
ten days until you are ready to plant them out. Again, do not start this until
the true leaves have appeared.
4)
Cool white fluorescent light is sufficient for seedlings that will be going
outside. The seedlings should be 3-4” from the light, with lights on for 15
hours a day. If you can’t set up this, the windowsill is still fine – watch for
excessive drying out as the sun gets stronger and higher.
5)
As the seedlings get taller, remove the covers cautiously – do it over the
course of one day.
6)
As seedlings get sturdier, soil should only require moistening twice a week.
7)
Feed plants only after watering.
8)
If any signs of damping off are seen (seedling flops at the point where stem
enters the soil) remove from tray/pot and dispose of this. Damping off can
spread very quickly through a group of seeds.
9)
Seedlings prefer to grow on at around 60°F/15°C.
10)
Two weeks before transplanting outside, cease feeding and reduce watering
slightly.
Transplanting to their final home
1)
Begin acclimatization one week before transplanting outside. Start this on a
mild windless, preferably overcast day.
2)
Place plants in a sheltered spot with filtered light, Leave out for ½ day.
Increase this exposure progressively each day.
3)
Water the bed where the seedlings are to go twenty-four hours before transplant.
4)
Add bone meal, wood ash or blood meal as required when digging.
5)
Transplant on a mild overcast day: if this is not possible, do in the evening.
6)
Water plants in flats one hour before transplant
7)
Shade transplants if they appear to be wilting
8)
Apply a two inch layer of mulch once the seedlings have grown up a bit.
Margaret Turner
References
Books
From Seed to
Bloom:
Eileen Powell, 1995.
Websites