i want to lay weed control fabric, how deep should i lay it.

For weed suppressing membrane to be successful, it needs to be just literally under the soil - if you want to plant, you just cut holes where you need to, then fit the membrane back round the base of the plant. You can either cover it with a thin layer of soil, or bark chips, or some other kind of mulching material.

Thankyou for the response, how would you go about improving the soil under the membrane by adding compost perhaps. sorry complete novice!!!

Dig it over to a spade's depth if you've not already done so, incorporating organic matter (rotted horse manure, organic soil conditioning compost from the garden centre, compost from your local council if they sell it from the recycling depot, spent mushroom compost, anything you can get hold of that's organic) plus chicken manure pellets. If you're going to plant, add some Growmore granules to the planting areas, or in the hole as you plant, but don't add Growmore past the end of July.

Just a word of warning about weed suppressing membrane. If you think you will ever want to re-design your borders....don't use it!!! A friend of mine inherited a garden with borders full of shrubs, all planted far too close together...when she came to take some out, found that membrane had been lain and the roots of the shrubs had all tangled and twisted and grown through the membrane. It has been a soul destroying task to get it all up...in fact she has had to employ a professional to sort out her problem. You have been warned.....

I'd agree with Amblealice - our predecessors laid it in several areas, and it is terrible stuff to remove! I use large scissors and get pieces out, but with great difficulty.

We laid membrane under a little twisting path through the flower garden, and covered it with gravel. After a year or two, despite the membrane, the gravel is full of grass and creeping weeds, and the horsetail (equisetum) forces its way through the membrane! Same thing has happened where we've put it around trees. The weeds just grow over and on top of the membrane and then it's a devil's own job to pull it all out.
So I've decided it's not worth using, except under a driveway where you can put down gravel and then spray frequently.

i laid a membrane all along the hidden side of the house where I store flower pots and general useful clutter. I had paving slabs laid on top and infilled with gravel. It has suppressed everything except the marestail, which is flourishing between the slabs.

Just to add to the forum, I find the stuff pretty annoying for planting, but it is very useful under pebbles, and the thicker version under paving works well. I don't use it in flowerbeds at all, prefer to use the hoe when necessary.