Is a weed barrier necessary?

Even with a weed barrier, I've always had weeds. Weed seeds fall on the soil from above, and my compost always contains weed seeds because my pile never heats up enough to kill them. (I compost what's available when it's available, so the C/N ratio is rarely ideal, and I don't turn my pile because I'm too lazy.)

I weed around my plants until they are 4-6" tall, then mulch heavily so, while there are always some weeds, they don't compete all that well with my plants.

I just moved to a new house, so I'll be starting my garden over this year. I'm considering skipping the weed barrier altogether when I set up my beds this time. Those of you who have made beds both with and without a weed barrier, what was your experience?

I found keeping up with weeds pretty easy. I did not use weed barriers. The MM is easy to keep weed free.

I'm new to SFG, so all of my beds have weed fabric if they are set on top of dirt. I use only Mel's Mix topped with wood chips as mulch in the summer. I found when I pulled up the tomato plants, the boxes were filled with roots. I had to hold down the weed fabric as I ripped out the fibrous roots. But, I didn't introduce any dirt into the MM and that made it really worth while.

As far as weeds, virtually none except for tomato volunteers from my homemade compost!!

It seems folks do it both ways, with weed fabric or cardboard, news papers, etc on the bottom, or with nothing but the native dirt/rocks.

Weed barrier is necessary if you're putting an 8" box on top of an established grassy yard.  Otherwise, grass and dirt will get mixed with your soilless mix as the roots spread.

I used thick cardboard in the boxes behind the house because they are 2-3 boards tall AND they were placed on compacted red clay and gravel that wouldn't even grow weeds after the bulldozers were done back there.  Then leveled the boxes inside with aged horsestall leavings, and then 8" of MM.

In the front yard, I used aged shredded woodchipped branches and leaves (B2E) to level inside the tall beds to 8" below the tops of the boards, leaving plenty of room for MM and mulch on top of that.  The beds are on a grassy yard, but the deep deep deep mulch layer on the bottom has prevented any weeds or grass from coming up through.

The mulch has NOT prevented moles from invading the yard... not sure about the beds yet, but am concerned.  The next beds in the front yard will have hardware cloth stapled to the bottoms, then very deep mulch, then 8" of MM, then more mulch.

So no weed cloth here, but I'm using extremely tall beds of 2 & 3 boards plus the thick layer of mulch inside on the bottoms to prevent weeds.

I did not use weed barrier because all of my existing boxes are set on previous garden area where I had been using the Lasagna Gardening sheet composting method. With that method you layer peat, leaves, grass clippings, kitchen scraps, manure, all in alternating layers, so it was basically MM minus the vermiculite. By setting my boxes on top, it gave me an additional 6-12 inches depth of good workable growing medium. I do get a few weeds, but not a great amount. One box is plagued with bindweed, but it just laughs at weed cloth anyway so it would not have helped! More severe bindweed measures will be taken before planting that box this season  .

GG

I used a weed barrier last year when setting up my beds.
I only did it because it was recommended. now if I didn't lay down a weed barrier, I would not be concerned about it.

Necessary? Not necessarily. Would I do it on a new, unknown property? Hell, yes! Especially if you're moving and you still have all those wonderful cardboard boxes to get rid of!