At last a sensible comment about allotments. Maybe I can be of some use to the public after all, and help promote Cardiff allotments at the same time. First off I will deal with some of your thinly veiled concerns. I too have a full time job which takes up about 40 of my weekly waking hours, I also have at least several hobbies, not least of which is lazing about wasting time. I think part of the trick is incorporating as many of the hobbies as possible into the allotmenting process.
Clearly some hobbies will be easier to incorporate than others. If knitting is high on your list you can make a lovely jumper to keep you warm as you pluck your sprouts for Christmas dinner. If you are a keen amateur belly dancer you can practice routines on your allotment neighbours and ensure a regular supply of seeds and spare veg. If you like to take a photo or two you can assemble a portfolio of sexy vegetable shots for sale to cookery and lifestyle magazines, thereby raising some cash in the process. Lazing about wasting time? Well there's no such thing as wasted time. Navel gazing gives the brain time to catch up and do a bit of filing and cross referencing. So even lazing can be useful, just choose a suitably warm and sunny day, or some suitably warm clothes, then head off down to the allotment for some serious loafing. It won't be long before ideas and inspiration for your plot start popping into your head uninvited. Eventually these ideas will become so insistent that even the expert idler will be driven to act upon them, and goodness will result.
Obviously some hobbies will be more useful than others, train spotting is useless (do people still do that?), unless of course your plot happens to be next to a railway track. Illegal invasion and occupation of far distant nations on a search for mythical WMD's is less useful, though it can help with the digging, depending on the munitions used. So, basically any hobby can have some positive impact on allotment productivity. Just use your imagination.
The next issue is time. As Groucho Marx once said "Time flies like an arrow. Fruit flies like a banana", this doesn't help us at all, so instead I'll give you some estimates.
Wait, no, perhaps I should ensure you have a plot before I go any further. I've just done a little research and it appears that many of the Cardiff sites are becoming increasingly full. So best get on the list as quickly as possible.
Your first port of call should be the allotment page of the Council website. Up in the top right hand corner you will see a small box with three links, one for a map, one for a list of sites and one for a price list. Don't bother with the map, it's rubbish, sorry, but it is. The list of sites is more useful and, as you will see, should you choose to have a look, there are still some pretty good sites available. The prices are so low as to be nominal, basically you're looking at paying around £30 for a standard plot, there are some variations by site but I have no idea why. So check the price list if you want but the payback far exceeds the outlay.
After you've decided on a site convenient for you simply give the site secretary a ring and they will tell you what to do next. This will probably involve going down to the site to view a plot. It's at this point that you might feel slightly alarmed and daunted.
1. Don't worry if you're shown a totally overgrown plot, covered in arm ripping brambles and knee tingling nettles. Ask the secretary if it can be cleared before you take ownership, they may call in the council or even do it themselves, the important thing is to ask, I promise they will be helpful.
2. Don't be daunted by the size, there is no requirement to immediately turn the entire plot into one of those kitchen gardens found in stately homes, with neat rows of cabbages and firm ripe peaches growing against the south wall. Start small, just use a quarter of the plot in the first year and bring in new sections as you feel comfortable. Remember to cover what you don't use to ensure the weeds are kept at bay.
3. Don't worry about any pristine plots around your potential new site, there is a lot of pride in allotmenteers but very little snobbery. Nobody will judge a new plot owner, they may be overzealous with advice at times, but only out of a desire to help. There is a good chance, in my experience, that in your first year you will successfully grow something on your plot that they have never managed on theirs, so just get stuck in and enjoy yourself.
Now, back to time. As Captain Lawrence Oates once said "I am just going outside and may be some time". Alas he wasn't just popping out to the allotment to pick some tomatoes for a nice ham sandwich, he was poncing about in the Antarctic looking for the South Pole. Had he been popping to the allotment he would have only taken about an hour two or three nights a week, and perhaps a four hour stint on the weekend. There are some pressure points in the year where a bit more time may be required, mid spring say, for preparation, and late summer for harvesting but these are the only real busy seasons, other than that not too much time is required. I suppose Oates only really had one season to worry about,bitter winter, and no vegetable worries, but I would strongly argue that between polar exploration and allotmenteering he made the wrong choice.
I fear I may be taking up too much of your time now. I hope this has been helpful but feel free to prompt me if I've been too vague, too specific or just too much. I look forward to hearing from you.

Louise wrote...
Thanks SuperDave! A special entry just for me!
I will definitely look into getting an allotment but I'm not sure that some of my favourite hobbies would go down too well if I started doing them on the allotment. Unless the old men wanted to watch of course! Hurry up with the photos!
Louise
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SuperDave replies...
I'm intrigued. And heartened that I've encouraged you to think about getting an allotment. Keep me informed!
Posted by: Louise | February 14, 2007 12:21 PM