Mulch is also an effective organic weed control. In can be used alone or on top of the cardboard/ newspaper method. Hand pulling and use of a trowel to chase roots is the most effective way to deal with weeds that make it through the barriers mentioned. I'm currently using a heavy mulch of Atlantic Coastal Hay in the garden; in the past I've used newspaper and cardboard too.

I like good old compost at 2" thick. It's hard to get that much though, so I like the news under straw too.

my 2 great enemies are nut sedge and bermuda grass. Bermuda is the one thing that even a foot thick mulch won't stop. I have found that big sheets of cardboard double layered so that the cracks and seams are staggered and covered, is the one thing that really works.
For sedge I grow something like okra that is tall and thick and will compete and take all the sun so the sedge can't grow.
Cardboard? yea, that works! Perfect for new trees too (with mulch under and over it)

I love this post by tclynx.

I use cardboard all the time. Been known to 'steal' it out of the trash.

But is it up to 'organic standards'?

It was made by companies who spew chemicals into the atmosphere and water supply. Newspaper is the same.

Therefore, I could argue quite convincingly that the use of cardboard is not up to organic 'standards'.

So is it organic?

You bet it is!

We are trying to live in harmony with our environment. We don't run around spraying DDT on every bug we see. We cut down on waste in the land-fills. We grab that cardboard when we see it. We raid the neighbors' trash to mulch our plants.

The thing a lot of people seem to not realize, is that "certified organic farming" is a whole lot different than organic gardening.

I call myself semi-organic because I will not even hesitate to hit a severe infestation of 'bad' bugs with an 'organic' poison.

I actually have more fun picking them off and sticking them in the soapy water.

Then I toss them in the compost.

Along with the soap that was made by a huge chemical company.

If bermuda is by itself then it is not that hard to kill. It gets much harder when it's mixed in with other grass. Last May I killed a bunch of bermuda by covering it with 2-6 inches of sand and 2 inches of mulch on top of that. It's called smothering.

I just read about agricultural vinegar, or 20-30% acetic acid. It can be used as an "herbicide." It works by removing the waxy cuticle from the leaf and thus drying the plant out. I guess it can work very quickly when the weather is dry and the sun is intense. The problem is that it is not approved by the EPA as an "herbicide" and so it can't really be marketed as such. It is sold in gallon jugs and advertised for lowering pH and cleaning farm equipment. The only problem is that because it's not systemic, it may not be as effective for plants with extensive roots systems like bermuda grass and ivy.

for the slugs I sort of spear them and turn it up so the birds come and feed gratefully. I do the same with grubs. Weeds get my fingers trailing the roots and pull them from below. Best way to be sure I got it all.