Plants I have listed here can all be grown in an unheated greenhouse through winter, providing you follow a few guidelines;
The plants for winter are; Winter Lettuce, Potatoes, Spinach, kale, cabbage, bok choy, Chinese cabbage, Onions, Spring
onions, Shallots, Peas, Broad beans, Garlic and Spinach...... More specific information further down this page)
Get the timing right and plant them before the days get too short and before it gets too cold.
Planting now means you will be ahead of the game in spring time.
Bear in mind, unless you have some form of lighting in your greenhouse very little actually grows in the Winter months of December and January. Things just tick over and then grow like mad
when the days start to lengthen again, so don't panic, turn up the heat or kick the greenhouse, its natures way of giving you time for Christmas shopping.
Information and varieties of plants for over-wintering
Winter Lettuce If you like salads there are at least a couple of winter hardy
lettuce that will grow in a cold greenhouse or poly-tunnel through the winter. Arctic King is one variety. Amazon gardening has loads of suggestions for all sorts of vegetables,
seeds and plants that will grow in a cold greenhouse or poly-tunnel through the winter. Click on any of the links on the right hand side below.
Kwiek and Little Gem and other varieties of
lettuce ( read the packet) can be sown in your greenhouse in October and then planted into seed trays when big enough and In December into pots.
No need to wait until the lettuce plants have
formed hearts, start harvesting when the leaves are big enough to add to salad. Leave some lettuce plants to grow on as hearted lettuce and cut as required. Tasty lettuces when shop supplies are
limited and expensive.
Potatoes Try growing early potatoes in old plastic buckets or any largish container or a flowerpot. Maris or most early potatoes (ask
your local supplier) can be grown this way. Three quarter fill each container with a compost of two parts soil from the garden one part compost from your
heap and one part sharp sand and plant one or two tubers in each container.
Bear in mind the containers will take up quite a bit of greenhouse floor space, but the taste of early home grown organic
potatoes make it worth while. Providing the weather isn't frosty and you need space to work in the greenhouse, the potatoes can be moved out of the greenhouse into the garden during the day
and back into the greenhouse at night.
Your first potatoes should be ready to harvest in May. Search around with your bare hands, pull out the biggest
and leave the others to grow on.
Spinach, kale, cabbage, bok choy, Chinese cabbage, and most root crops. Leeks, beets, carrots, turnips,
parsnips, radishes, and rutabagas and some varieties of onion can be grown through Winter in a greenhouse and you'll get a much earlier crop than if
you'd waited till spring.
There are quite a few varieties of onions sets that can be sown in a unheated greenhouse to
grow through Winter.
Electric is a good red set, Radar a good yellow and Shakespeare is a highly reliable white.
White Lisbon Winter Hardy is a good one to grow through winter.
Jermor and other varieties are available from most garden centers for planting up until
Sowing pea seeds now, especially in mild areas will produce a crop in late spring, even earlier if you are
starting them of in a unheated greenhouse. If you sow direct into the ground, plant them one inch deep and relatively closely at about one inch apart, to make up for a higher
loss rate. Meteor is a first early variety and overwinters well.
gave us this useful tip for starting of early peas in a greenhouse, using a length of guttering.
He drilled holes for drainage, lined the guttering with a sheet of news paper,
filled it with compost, then planted the peas and left the whole lot in the greenhouse until the peas had lovely long shoots. Then dug a small trench and slid the contents of the
guttering straight into the ground....Result...Fantastic strong plants.
Autumn sown broad beans will be ready a month earlier than those sown in April, and they won't
get black fly. Good autumn varieties are Aquadulce Claudia (AGM) and Super Aquadulce.
Garlic is easy to grow. Plant the cloves individually to a depth of 2.5in deep on light soils
and about 1 inch on heavy soils, about one foot apart each way.
Solent Wight ,stores well and has large cloves, Provincehas huge cloves.
Varieties that can be sown in a unheated greenhouse from now until the end of October are
Riccio d'Asti and Merlo Nero.