Reduce watering and feeding of houseplants as the days shorten. Ensure
that there is adequate ventilation in the greenhouse or conservatory,
perhaps opening vents for an hour or two on milder days to encourage air
circulation.Remember that cacti need very little water, and no
feeding, over the winter. Keep them barely moist until the spring, when
they will be coming up to flowering and will therefore appreciate extra
water and feed.
Clivia benefit similarly from
a dormant period over winter, with less watering, feeding, and lower
light levels.
Pot up Hippeastrum
(amaryllis), and bring them back into active growth with regular
watering and feeding. They should give you beautiful flowers for the new
year.
If your Christmas cactus (Schlumbergera
truncata and S. x buckleyi)
failed to set flower buds, it may be that the temperature is too high
(above 18°C/65°F, or that the plant is receiving light from an
artificial light source after dark. Try moving the cactus into cooler
conditions or away from night lighting.
Cyclamen persicum (often given
as a winter pot plant) appreciates a cool room with good light. It is
best watered from below (i.e. into the saucer, not the pot), as wetting
the leaves can easily result in fungal infections and rotting off.
Cool conditions and regular watering will help keep potted indoor
azaleas looking good for longer. Remember to water azaleas with
rainwater collected in a rain butt, not with tap water.
Avoid buying poinsettias that have been accidentally chilled,
particularly those sold from street stalls on cold days. Once home,
place them in a warm, light place, away from drafts, to ensure they last
for as long as possible.
Place hyacinths in a cool, bright place in the home. If it's too
warm, the leaves will elongate and the flowers will fade quickly.
Put up insulating material such as bubble wrap on the inside of the
greenhouse, if not already done.
Check that greenhouse heaters are functioning properly. Invest in a
maximum-minimum thermometer to enable accurate monitoring of the
temperature in your greenhouse.
Check that light levels are sufficient for houseplants. They will
need light to carry on over the winter, and can easily be forgotten in a
back or spare room that receives little natural light, or with the
curtains left drawn. They are best moved to sunny windowsill until March
next year.
Clear leaves and twigs from greenhouse and shed gutters.
Pest & disease watch
Keep an eye out for overwintering pests such as whitefly or red
spider mite and treat accordingly. Nooks and crannies, and the bark of
woody houseplants and vines, can harbour mealybugs and scale insect
nymphs, for example.
Occasionally ventilating the greenhouse or conservatory for an hour
or two on mild days will help reduce fungal infections.
Regularly deadhead winter-flowering plants in the home and
greenhouse, to prevent problems with grey mould (Botrytis).
Cyclamen are particularly prone to this problem.
This is a good time to clean all your old pots and seed trays, so
that they are ready for next spring’s flurry of activity. Thorough
cleaning will reduce pest and disease problems, and will reduce your
propagation and sowing problems.
Regularly pick and sweep up fallen debris to prevent disease
appearing and spreading.