Cold
frame or hardwood
plant house to provide plants with a stable growing environment
and to gently get used to life outside.
Fleece
jackets can be put over plants in containers to provide
instant protection from frost.
Slug
deterrents such as copper tape or biological pest control.
Strulch
garden mulch
Hardening off is a gardening term referring to the need to allow plants
time to get used to different temperatures and to being outside.
If plants have grown in a greenhouse or on a warm windowsill they are
used to quite warm temperatures on a regular basis. They have not
learned how to cope with wind or rain. The plants have been living
in a sheltered setting. If they are planted straight into the garden
they will struggle to survive. Their growth will certainly be slowed
down.
Plants described as perennials on the seed packets can be hardened off
at any time.
Half-hardy plants such as nasturtiums can be hardened off from the
end of April. These plants can cope with a very light air frost
provided they are hardened off.
Annual plants such as courgettes and tomatoes should be hardened off
at the end of May, beginning of June. These plants cannot cope
with even the smallest amount of frost.
• Put the trays or pots outside on warm days.
• Bring them inside again at night time.
• Do this for several days.
• Then leave them outside at night and see how they cope.
• Do not leave outside if frost is forecast.
• Put the plants into their permanent planting spot in the vegetable
garden.
While plants are inside, you can help them harden off by gently
brushing over the top of the plants with the edge of a piece of card. Do
this for one minute every day. Each day brush in a different direction.
This helps strengthen the plant. But they will still need to
get used to different temperatures.
• Fasten the lid open just a little at first.
• As each day passes, open the lid further.
• Finally, leave the lid open at night.
• Keep the lid closed if frost is forecast.
• Plant outside in their permanent planting position. Water
well.
• Large pots can be left outside but covered with a fleece jacket overnight.
• Take the jacket off during the day. This will provide ventilation
for the plants and allow hardening off to take place.
• When the plant or plants are strong enough remove the fleece jacket
at night.
• Don't forget to put the jacket on if there is any possibility of
an air frost.
Put a mulch around the young plants to maintain moisture in the soil.
A slug deterrent should be placed around vulnerable plants such as strawberries
or lettuce. This will prevent slugs from eating the young plants.
