In winter, your garden may not be the first thing on your mind. But if you have a polytunnel you could still have plenty of crops on the go. While a polytunnel will make winter growing far easier, and will keep off the worst of the winter chill. But if the weather turns very cold, many plants will still need a little extra protection against frost in an unheated polytunnel.
Sustainable growing is all about making the most of the natural, renewable resources at your disposal. So while horticultural fleece, or bubble wrap, or single use plastic bottles recycled for use as cloches could all be used to great effect, let us take a look at some of the natural materials that can be used instead to protect your plants in winter.
Straw has long been used to protect winter crops and is still a wonderful material to use today. Straw can retain a lot of heat and the dry mulch material will not attract slugs or snails into your tunnel. Straw is such a good insulator that it also has applications in eco house building. In your polytunnel, spreading straw around your plants can help to keep a hard frost away from tender roots. As straw, and other organic materials like it, decay, they will also generally warm your polytunnel, helping to keep frost at bay.
If you do not live on or near farmland, however, straw is not always easy to obtain. Fortunately, there are other options. Bracken also has a long history of use in certain areas. It shares many characteristics with straw and is also a good material to use as a thick mulch to keep plants from winter damage. If you live in an upland area, bracken may be a natural material that is found in abundance and, if so, could be a good choice for use in your polytunnel.
If neither straw nor bracken are readily available where you live, it is still possible to use natural materials to protect plants in your polytunnel in winter. Autumn leaves can also be used to mulch around growing plants and can also cover garlic and onion bulbs until the spring. Autumn leaves are available to almost everyone and are almost invariably something everyone can gather in abundance, either from their own land or from a common area nearby. As they mulch down, autumn leaves will not onto protect plants' roots but will also add nutrition to the soil.