PLANNING TO GROW
A growing plan is needed for winter planting. Think about what you would like to grow. Seeds need to be planted in August or early September at the latest. The daylight hours start to go down in September, and soil temperature starts to cool. Planting early allows for growth before the dormant period in winter. Polytunnels managed communally could be thinking about crop rotation when making a plan.
Light and some warmth returns in late winter and early spring, and growth starts again, giving you some very early crops.
Miners lettuce (winter purslane), or lambs’ lettuce are grown/harvested in winter, and the dormant main lettuce varieties react quickly to the early spring of polytunnels. We have early strawberries in hanging baskets in April or May at the latest. They make use of warmer air trapped higher in the tunnels.
We have had great success with perpetual spinach with autumnal seed sowing. It gives a great early harvest. Runner beans grown in spring/summer fare much better than those outside as they don’t like much wind. Garlic does very well but should be left in a bit longer, into late spring to get fatter. There has been some success with planting potatoes for Christmas in the tunnels, but the most success was had by planting potatoes in February and lifting them about the end of April. Thyme and most other herbs can be grown inside. Chards can survive in low temperatures. Peas may be grown early, but watch out for mice damage. Beetroots have also been very successful in our tunnels over winter, and some of us had great success with bulb fennel. Carrots favour the dry conditions in the tunnel for winter growing.
Plants will not need much water in winter, and it is important to control the moisture as the soil should not be too wet. Test the soil condition and moisture at a depth of 4 inches. Watering should be done by hand with tepid water. Too much watering could lead to fungal diseases. Keeping the beds moist in winter will help prevent slaters and ants from taking hold.