I don't see anything wrong with putting rock over the old mulch other than the height being a problem, you don't want rocks being kicked in the grass. I'd just be worried about keeping the rock and grass separated so you're not going over rocks with your lawnmower. Use masonry edging, forget the plastic stuff, and get the rock about the same height as the grass.

Always put cassaron in there too, weeds will come up eventually, even in the rocks.

 

my question is can i use a 2nd landscaping fabric?

rocks, landscaping fabric, 3" of old mulch and then the original landscape fabric from 8 years ago

 

You can use the method you are referring to, but it might be more beneficial to remove the old mulch and fabric and start fresh.
You've got a current layer of composting mulch that aids in retaining moisture, but it's not keeping the weeds back anymore; so if you fabric and rock over that, it won't be long before those well fed weeds find an opening and spring back to life in your new install.
If it were my home, I would remove the mulch and store it somewhere to continue composting, or integrate it into the planting bed; then re-fabric and rock mulch over that.

 

the weeds arent that bad currently........will the water leach through 2 layers? is the 2nd layer going to starve the bushes/trees of moisture?

 

They've not starved to this point, and after 8 years their water requirements will be much less as they've established.
Also, it depends on your irrigation system...is it sprinkled or drip fed? Whatever it is, it's been working so far.
I only made the recommendation I did because I see a use for the old mulch in another application; and also because you mentioned that you have weeds in your current installation...so I figured that it might be more beneficial just to remove one problem and have a clean install.

 

my watering source is rain.....these are all established trees and plants...i will be adding a few new ones

i dont know how much the fabric stops water from running through....

 

As long as your new planting are properly 'cut in', you shouldn't have an issue with water reaching the roots; but you are right to be concerned about penetration through the fabric...most water will just run off under your inorganic mulch.
In the past we would be sure to form a 'water well' around the plant after we put it in the ground, and that would keep water funneling to the root zone until it was established.
Also, I've only used fabrics for inorganic mulches...if it was an organic mulch we would not install fabric unless it was specified in the scope of work.

 

I hate that stuff. Weeds germinate from above, and that stuff does nothing to prevent those weeds from growing. It is also a m.f. to pull the weeds that weave through the fabric. I would get rid of the fabric altogether.

If you want to lay a barrier, I suggest newspaper. The paper will degenerate over time, but offers a barrier for a spell. Also, it's easy to sink a shovel through that stuff versus that landscape stuff.

 

I hate that stuff. Weeds germinate from above, and that stuff does nothing to prevent those weeds from growing. It is also a m.f. to pull the weeds that weave through the fabric. I would get rid of the fabric altogether.

This is spot on. Fabric is good for drainage lines and such, not for gardens.n when, not if the weeds come through it, you can uproot the plants you want to keep. Take it out.

 

I just don't understand how so many landscape outfits use that stuff.

 

i decided to pull up the old stuff....it wasnt a big deal

i found almost nothing that grew up through it....the old stuff did its job well, so im not sure what some of you guys are talking about

i had gotten 2 bids to redo it $18,900 and $12,300

as a plumber i found those bids way out of hand.....$2,500 in materials(and i found the exact same materials listed on one of the bids)....if i pay myself $118 an hour(my plumber wage) and $50 for my laborer it appears we will be able to complete the job in 40 hours total....i can do the job for around $6,000.....i dont get how they come up with their prices.....since they are paying college kids w/o benefits....i finally found a trade that charges more than i do!!!!!

i had to ask the $18k one if they hire doctors/lawyers to do their installs

i may quit the plumbing trade and start a landscaping business afterwards

if i assume they pay their guys $12 an hour and give them the 40 hours that im doing it (im age 43 and my laborer is 54)...thow on insurance and some business expenses i figure each guy costs them $20-25......they would be making $11k profit off of me

 

i found almost nothing that grew up through it....the old stuff did its job well, so im not sure what some of you guys are talking about

Then be thankful, because if the weeds had grown through it you find out why it sucks so much.

 

the old stuff was a black plastic material

the new stuff is grey and more of a fabric(it costs more)

landscaping work sure S U C K S....almost ready to put the fabric down, stone comes tomorrow....hope to be 100% by the end of the day Friday

im taking tomorrow off because its raining and i need a day to recover(im old)

 

Just saying, it's not the stuff that grows from below. If there is a void, the weed (unwanted growth) will find it's way through. I find that the problem with that stuff is that many unwanted weeds grow from above, via winds, birds...or whatever. If not addressed in a quick manner, the roots tend to entwine throughout the fabric. Also, it's a pain in the but to put a shovel through the fabric. Usually, one has to get a utility knife.

As mentioned earlier, I hate that stuff, and think it actually does more harm than good.

 

I believe the stuff is more for soil stabilization than weed prevention.

As stated previously, the weed come from above and the roots grow through the fabric.

It usually takes a few years on a new hardscape installs, including inorganic beds, until weed start popping up.
It takes a while for dirt and pollen to fill in between bricks, flags and river stones or whatever, to create a suitable environment for the weed to germinate.

keep after them and it's not a problem, or put down a pre-emergent.

As long as you keep organic mulch replenished you should never have weeds.
Maybe a mushroom or two that tag along with your mulch, depending where your getting it.

D.