Old pond

Hi all.
I've just moved into a house which had a large (10 ft square ish) old outdoor fish tank at the bottom of the garden with a rubber liner. I've punctured the liner (a few months ago now) so the water has drained out but there's a LOT of old sludge in the tank from various dirt and garden matter (lots of overhanging trees/branches).
Presumably this sludge is just composting gunk.
Now I'd like to turn the area into a greehouse type growing area by putting a polycarb rood on it (I've got some sheets and roofing gear going spare that I want to use) and plant some tomatoes and other veg and salad in there.
I'm tempted to pour a few BIG bags of soil on top of the sludge and plant in that.
What do people think - it'll work and be safe and decent growing fodder or not and it'll have to go (v difficult job)?
Thanks,
Tom

p.s. I'm new to growing etc so bear with me if the above sounds daft!

 

Welcome to GC, Tom

The old "sludge" would work a treat on your compost heap. Now, to be fair, I'm a beginner gardener, but, my first thoughts are that nutrient rich stuff should be put on top of less nutrient rich stuff. So, get your sludge OUT and use it as a top dressing (as opposed to putting bags of soil on top if it). Why? Because worms will drag the goodness enriched stuff (sludge) down through any soil and combine the two.

That is simply my two penny worth on the sludge/soil scenario. More experienced gardeners will be along to advise you on the other issues you mention

 

Clear out the sludge, repair the leak and fit a valve, build your greenhouse over the pond and leaving a central path, have raised beds down either side.

Cheers, Tony.

 

If the pond is not very deep, and just "punctured", it will not drain properly to function properly as a bed. Better to remove the liner, sort out the soil under the pond (e.g. loosen it a bit - it won't have had any air for years) and then put topsoil in if that is what you want.

Agree with putting the "gunk" on the compost heap. It will have rooted down with no air, anaerobically, so will be rank, and needs to be mixed with other materials to cheer it up, but after 6 months or so it will be very worthwhile.