Plants for winter are; Winter Lettuce, Potatoes, Spinach, kale, cabbage, Bok choy, Chinese cabbage, Onions, Shallots, Peas, Broad beans, Garlic and Spinach. These plants can all be grown in an unheated greenhouse through winter, providing you follow a few guidelines;
and Little Gem varieties of lettuce 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 and form hearts then cut as required. Tasty lettuces when shop supplies are limited and expensive!
The containers will take up quite a bit of greenhouse floor space, but the taste of early homegrown organic potatoes make it worth while. Providing the weather isn't frosty. If you need space 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 will get a much earlier crop than if you had waited until spring.
Steve 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.
Broad beans, 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, Garlic is easy to grow. Plant the cloves individually to a depth of 2.5in deep on light soils and about one inch on heavy soils, about one foot apart each way. Solent Wight ,stores well and has large cloves, Provincehas huge cloves.