Perhaps I was unclear.
The raised beds likely are level - it's the garden that has a gentle slope.
The weed barrier is for between the beds (the rows)- I use a weed paper with fertilizer in the beds to keep the weeds down (breaks down during the season but the weeds generally don't have a chance to take over.

Between the beds all the mulch washed away and the weeds became unmanageable.

Andrew

We use a profession grade weed cloth called double bonded weed cloth or erosion cloth.
You can get it at professional irrigation and landscape supply shops.
It has the texture of dense thick felt. It is permeable .
It's the same stuff that the hiway construction crews use when they lay down asphalt.

If you are using mulch as a top dressing on top of a weed barrier cloth you might find the shredded or double grind mulch to hold better on steep to moderate slopes.

My back yard paths are 11 years old and have double bonded weed barrier cloth under 2 inches of crushed granite fines. I rarely have to hand weed the paths.

attached is a photo of what it looks like :
{{gwi:47631}}From Figone

Do your raised beds have raised edgings of any sort? Or is it that they are edged but overall the slope of the land overcomes the height of the edging?

The garden itself is surrounded by plastic edging - but it is almost level with the ground at some points. Given the magnitude of the rains we get in the Spring, I get a lot of water run-off through the garden which takes the mulch with it (the beds are 12" tall and don't have any erosion issues.

If I could find a plastic edging with a much higher profile I could likely direct the water flow around/away from the garden or keep the mulch inside - I don't know of any sources for 6" or higher edging.

Does this answer your question?

Andrew

Trex ( composite lumber ) mades a 2x6. I believe they also make a 2x8 as well.
That will give you your additional height.

Another option might be to consider digging a shallow open v- trench in front of the raised bed so that the water has a channel to flow in and then out.
If the open v-ditch is not an option than a trench drain infront of the bed might work, take time to install the proper percentage of slope so that the water is carried away rather than sitting in a gravel sump.

Again, the problem isn't the raised beds.

My garden is 35 x 35 and surrounded by a fence which, while pretty, doesn't keep the rabbits out - that's a different thread .

Inside the garden are a number of raised beds - some are North-South and some are oriented East-West (both desriptions should really be followed by 'ish').

The space inside the garden between the beds has been covered in mulch to keep weeds down and make walking barefoot/having kids play/etc. more pleasant.

The mulch has (and likely may continue to) wash away in the wet Spring and summer rains we've been having.

What I would like is to put down a weed barrier and then remulch - likely with root mulch which will resist floating away.

I'm looking for a good barrier at a good price; I think we have the type defined, I don't know any good sources online.

If I could raise the edging, that would help divert the water at it gently flows down towards the garden. I've never seen a really high profile edging - perhaps someone can point me to a good product there.

Thanks for everyone's input. It is much appreciated.

Andrew

No comprendo.
......"put down a weed barrier and then remulch - likely with root mulch which will resist floating away."
Are you asking for a ground cover plant , ie "root mulch" ?

The trex that I suggested can be used as a high profile edging - google will help you.

If you have " the type defined " then it might be helpful if you shared that info. .... cuz I'm just not gett'n it.

If your mulch is floating away it sounds like you have a excessive water sheet flowing across the yard .
Address the sheet flow with either a grade change or drainage.

below is a photo of a raised bed garden that had a terrible surface and subsurface drainage problem.
We addressed the subsurface and surface drainage by installing some drains and augmenting the topo.
Instead of wood bark mulch , a soft rounded river rock was used.

during construction - note the roll of weed barrier cloth in the foreground on the deck and the raised edges :
{{gwi:47632}}From Figone

during construction with stone mulch applied over double bonded weed cloth.
{{gwi:47633}}From Figone

Trying to help you out here but I'm a little slow on the uptake . The 'root mulch' thing has me scratching my head.

Are you talking about typical rain causing wash out of the mulch or the ten inches of rain your area got in one day this summer?

If its the latter, you can landscape your property to deal with the once in 100 year rain fall, or you can clean stuff up one time in 100 years.

just to be clear - black plastic will not work in this situation no matter how much you want it to. also, landscape fabric is not "weed block" it is a material to use with other materials to minimize weeds - when you use it in the proper way (as dd described above). if you put down "landscape fabric" or "weed block fabric" and then mulch on top of it, you will grow weeds; weeds that are harder to pull out because they are now rooted into a nice layer of landscape fabric.

To give you some solutions, you can put down peastone, stone or as they do here in farmland - straw - but be sure its straw not hay.