Great gardeners say that you can judge a good garden by how it looks in winter. That being the case, my garden is not great at all. As for my vegetable patch, it shames me to say that since we ate part of the last overgrown marrow, we have had nothing from it at all. Yet there is one plant in my garden that will yield a tiny crop in February, and that is sea kale, a small patch of which is planted by a wall. This was given to me by a friend who lives on the Hampshire coast. She tells me the blue-grey seaside plant, a member of the cabbage family, will be inedible and tough unless the plants are “forced”. To force a plant you block out light, encouraging stalks to grow quickly as they search desperately for light. If the plant is outside, you cover it with a clay forcing pot (a