Humm, it doesn't sound like a good idea, but I can't exactly tell you why. Something about fish ponds and weed killer says "bad Idea." Personally, I don't like fish ponds - high upkeep, smelly, mosquito breeding ground, red tail hawks, etc. It doesn't look like too big of a space. I would put garden fork & spade to good use - maybe waiting until everything dies down for winter would be easier on your back. You don't have to do it all at once or worry about the residual effects of the chemicals.

Bathgate, this isn't a fish pond, Hank created it as such to start with and then decided against, filled in, and turned into a rockery... Hank if you don't want to plant for a wee while why not cover in black plastic or old carpet that will suppress any weeds. I doubt you need to treat with weedkiller.

don't use the weed-killer. every couple of days hoe over the surface and that will kill any emerging seeds, bring hidden ones up to the surface. then when they germinate they will get hoed off too. or do as Moongrower suggests.

The carpeting would work - good idea. I also heard cardboard and thick layers of newspaper also work. I much prefer the rockery idea or zen garden.

If available in the UK, sprinkle on weed preventer now and in the spring watering in each application since what you are dealing with here are weed seeds not yet germinated. I have four fishponds and one without fish, they look and smell fine. As far as the upkeep, no problem, thats what the garden is for, to get out and get some outdoor activity on a daily basis. My only problem was with mink which took over 50 fish from my ponds this past winter. I you feel that you won't have the time then a rockery is certainly the way to go.

Thanks very much all, i'll be on it tomorrow - I have a large old carpet in the garage. Glad to hear I don't really need weedkiller.

Pre emergent weedkillers aren't available to amateur gardeners in the UK anyway - most weedkillers sold here work 'through the green', that is, you have to spray or drench growing plants. You can buy one called Paradise if you can find it, and that keeps everything from growing for six months to a year.... old carpet is probably best.

My son has already had a go at me for digging his primroses up. I should have asked him first.

If you've still got the primroses, you can replant them, water well and they'll likely recover.

Thanks, I'll have a good root in the green bin for them. Just going to pick up a 6ft x 6 ft carper - mine wasn't quite big enough.