Okay, here's my critique. You probably did not design it, actually, you just built it--a big raised bed with a fence around it. Ideally, I would use a completely different design for a fully-fenced garden as for one not fenced--both as to dimensions and where the garden actually "is" with regard to the house and to the fence and to any paths or stepping stones that will be needed. However, you were able to take some advantage of where you attached the fencing to the perimeter. You can retrofit it now with some kind of step stones or paths in order to try to work in it. It's too close to the house so you lose the ability move very well back there or to work freely through the back fence or to run a wheelbarrow back there. You lose a little bit of some space advantage you could have had to let larger plants (indeterminate tomatoes; peas and beans) which like to spill out over the back sides--but you could still place them at the ends. These types of vegetables are really fun to grow in places where you can just saunter up to pick them at eye level (I am revealing my middle-agedness here). Of course, it isn't that much fun to try to work through the squares of fence, so you will mostly want to work from inside. If you put a path through the middle then will still have a few feet on either side for your crops. You can have a lot of fun with this garden regardless and learn a lot about growing different types of stuff. I always feel pressure to try to put as much as possible in the small veggie garden, but sometimes that can take the fun out of it (pressure! pressure!) as much as it can be fun. But if you do check out some of the photos and articles on small-space or square foot gardening, they will have some helpful tips on where to place different vegetables with regard to each other (height and growth patterns, time to maturity, multi-season planting). I would work out your pathways, and plan on enjoying plenty of tomatoes (next year) , herbs, and lettuces. In your zone, you can plant cilantro and parsley now and it will grow all winter and thaw out great after freezes. Also all kinds of lettuces and greens as suggested above.

According to a "tomato timeline" posted here before and linked many times, It take about 52 days from the bud to the ripe fruit. This is for large fruits in the middle of growing season. But it can take shorter/less time for cherry types/sizes and smaller tomatoes. But I think later in the season and in cooler climates it can even take longer. So then you have to factor in the effect of late season cool weather that will slow down the growth and ripening of fruits significantly. For example my FFD is around mid November but our October weather will be too cold (and rainy/cloudy). So I would count backward 50 days from my average frost date ( say Nov. 10 -20th ) and start my pinch off schedule ( Sep 20 to 30th). And that is an optimistic outlook here. Even then probably I will end up with plenty of green tomatoes to pickle. So you have to decide what is best for you.

I really don't understand why you need Christmas lights if you've got big fluorescents there. Just look at the wattage. That's how much heat/light you're already pumping into that area. Sorry, but did you ever tell us what temperature your garage is actually at? You say It is "damned cold". It would have to be pretty cold for those fluorescent bulbs not to do a decent job of keeping things warm IF they were suitably covered. The colder it is, the more cover you need. If it's "damned cold" you just need a damned good layer of insulation on top of the bulbs. Throw a sleeping bag over the setup, for goodness sake. The tomatoes will be fine underneath. as long as it doesn't get too hot. An adult human radiates about 100 watts of heat. Probably not too different than your fluorescent bulbs. So if a sleeping bag would keep you comfy in your garage, it'll keep anything under those bulbs comfy in your garage. That being said, I'd be very careful about throwing a lot of insulation over incandescent bulbs. We're talking fire hazard.

Hi Tom - since you are in the UK it is highly probable that the soil in your garden is perfectly fine for growing vegetables. Unless you are in a new house which has had the topsoil removed by the builder there is absolutely no need at all to buy in extra soil. Start a compost heap and use the results in your garden. Alternatively use trench composting. Until your own compost is ready you could buy some sacks of composted manure or something similar but to be perfectly honest with you I have grown vegetables on my allotment for decades and never bought in anything except an occasional load of farmyard manure and some pelleted chicken manure. Manufacturers are set on selling and they prey on beginners with all sorts of 'advice' about what you need. Trying to flog top soil to people who don't need it is a scam in my view. In your first season I suggest you just thoroughly cultivate the soil you have and see what happens. Don't spend any more money than necessary for basic tools and materials just in case it turns out you are not such a keen gardener after all. BTW - most posters on this site are based in the US where gardening habits are rather different and a lot of interventions appear to be the norm. One example is the use of soil tests which are rare in the UK outside commercial outfits. UK methods are much more laid back, possibly because our climate is relatively forgiving and our soils tend to be pretty amenable everywhere.