The English Garden – September 2019

88 THE ENGLISH GARDEN SEPTEMBER 2019

Best greenhouse heaters

Rootrainers or plant eight seeds
in a 12.5cm diameter pot, water
thoroughly and leave in the
greenhouse until germination.
Only when you see shoots
emerging should you water
again. During winter, grow them
‘hard’, taking them outside on
sunny days, and you’ll get bushy
plants with well-established root
systems ready to go outside in
spring. They may need a little
extra protection in the form of
a sheet or two of fl eece should
temperatures drop below -5°C
inside the greenhouse.
Autumn is the time to plant
bulbs such as ‘Paperwhite’
narcissus in pots for Christmas
displays. You could also start
forced hyacinths for festive
fl owers. Most cultivars need
around 8-10 weeks in cool
conditions before you can bring them into the
warmth of the house to bloom, but remember that
they also need to be kept in the dark, so put their
pots inside a black polythene bag or cardboard box.
In late autumn, you could try forcing other plants.
If you have plenty in the garden, try digging up a
clump of lily-of-the-valley (convallaria) and potting
it up in the greenhouse. In a heated greenhouse,
the plant will start to grow again, producing its
beautifully scented fl owers in early spring, when you
can bring its pot into the house to enjoy.
September is not too late to sow winter salads
under glass. These crops are naturally hardy so
don’t need heat to grow, just protection from the

Above left Paperwhite

narcissi grown in the

greenhouse will bloom

in time for Christmas.

Above right Autumn is

the best time to sow

sweet peas; grow them

on in a cold greenhouse

for strong, bushy plants.

AUTUMN GREENHOUSE

Biogreen Phoenix

from £214

Buy this electric fan heater direct

from biogreen.world or from UK

suppliers such as twowests.co.uk

Hylite Slimline Green Eco Heater

£32.50

Electric tubular heaters can be fi xed

to the greenhouse wall or stood on

the fl oor to make e„ cient use of

space. greenhousepeople.co.uk

FirTreeProheater

from£155

Arangeofthermostaticgas-powered

heaterswithdi†erentoutputsforsmall

tolargegreenhouses.kdev.co.uk

worst of the winter cold and wet for a good harvest

of umblemished leaves. Try American cress, lamb’s

lettuce, winter lettuce cultivars such as ‘All The Year

Round’ or ‘Arctic King’, mizuna or mibuna, and

pak choi. You could also try sowing small trays with

micro-leaves seeds for garnishes, or pea shoots.

If you’re attempting to grow anything in the

greenhouse over winter, keep nearby glass free

of bubble-wrap insulation, since the plastic will

dramatically reduce the amount of light that can

reach through to the plants inside. And, as always,

remember that having good ventilation and air

fl ow around the plants is crucial, so open doors and

windows as often as possible on crisp winter days. ■

IMAGES

GAP/ELKE BORKOWSKI; JONATHAN BUCKLEY