Hi! I also use recycling boxes for veg. I've grown aubergine and chilli peppers in mine this year but both of those were a spring start.
You could also start off some peas/beans in them at this time of year or later in October, maybe six (three down each long side, but not right at the edge). Do you have any empty coke bottles (the large size - 2 or 3 litres is it?) as they would be good as cloches for the seedlings. cut off the base, chuck the lid away, and put them right-way-up over each seedling. Use a variety which specifies it is good for overwintering though.
Other things which overwinter are lots of the onion family (shallots, garlic) and of course winter salad crops like lettuces and spinach.
Hi, you can plant some potatoes at this time and dig them for christmas dinner. other options include buying plug plants of anything winter grown like sprouting broccoli or cabbage, but they can be tricky.. things like herbs and salads will still grow from seed up until the first frost. you can also plan things like runner beans or onions which if planted in late autumn will be ready earler in the spring. the best value things are tomatoes and salads, because they are expensive and take up little space, but tomatoes will need to wait until late spring, sorry!!! great you are having a go though!!! good luck!!
greengoose wouldn't potting compost be a bit expensive? I would say all-purpose compost should be all right for a slow-starting veg box like this, then when it comes to spring, water and feed with the appropriate mix for what you're growing. I'm not sure if it's available at this time of year but you can also get veg-growing compost which has added goodness (oh probably naughty peat or something though).
For one recycling box, you might need more than one standard bag of compost by the way. Maybe three bags for two boxes? Another useful thing to do if you're going to grow winter salads would be to get some copper tape (sticky roll like sellotape) and that will stop the slugs coming and munching it. you can buy it on Ebay pretty cheaply.
Sorry LEX your right, I meant ordinary compost (du). Might be useful to get the recycled stuff from the council. Its good to put something a bit richer at the bottom though, especially if you are needing good root development, or so my friend-who-knows-all-about-it has told me!
I've just planted peas and potatoes in the greenhouse. Peas will go out once they have germinated and potatoes will stay in greenhouse to protect them from frost (and hopefully be ready for Christmas )
I have also just put garlic and shallots straight into the ground in the allotment.