A:

You can start chitting your early and maincrop seed potatoes in February, but the best time to plant is in early to mid spring. As for growing vegetables in your polytunnels, you have lots of options. Spinach, kale, and some varieties of lettuce will live through the winter in a polytunnel. Certain kinds of onion work well from an autumn sowing, and you'll get a much earlier crop than if you'd waited until spring. Other possibilities are cabbage, Pak Choy, Chinese cabbage, and most root crops. Leeks, beets, carrots, turnips, parsnips and radishes, can be sown for winter harvest

A:

Now is the perfect time to start thinking about growing potatoes, as they need to be chitted before planting. Chitting just encourages shoots to grow before you pop them in the soil in early spring. The onion sets can be planted in March or April, while carrot seeds can be sown from late February as long as they are protected.

A:

The purpose of crop rotation is to reduce build-up of soil borne pests and diseases, and continuous cropping of the same vegetable can lead to an inbalance of soil nutrients. The plants you mention should be fine to grow in the same spot as the beans this year, but you will need to add plenty of organic matter to the area before planting and I wouldn't recommend growing the carrots or sprouts in the same spot next year. Even if the area is small, it really will help if you can try and work out a crop rotation to avoid problems in the future.