I pretty much concur with Greg B. that changing to lawn will require more maintenance, though it will be different type. Have you explored treating rock mulch with pre-emergent herbicides in order to cut down on weeds?

Round up is available at low cost from the right sources. The home stores generally get about $80 for a half gallon of 41% concentrate. 2.5oz of concentrate makes 1 gallon of spray.

You can get 1 gal of 41% from Amazon for $120 or Costco/Sams Club for $100. John Deere Landscapes and other commercial landscape suppliers sell 1.67gal of generic for $100. AM Leonard sells the generic 1gal for $40 or 2.5 gal for $60. AM Leonard has free freight specials 1-2 times a year.

http://www.amleo.com/41%2525-glyphosate-herbicide/p/VP-CL41/ 2.5 gal should be enough for that yard for a decade, maybe two.

I can't help with info on pre-emergents.

You are saying that it has been pretty bad in the past, at times. Weeds quickly produce seeds and GUARANTY that there will be many more of them in the future. Weeds seeds will last 2-3 years in the soil so it's important to keep ahead of them for at least that long to make sure they don't breed and make more of themselves. Begin with glyphosate, but this only kills existing weeds. Pre-emergent would attack newly germinating seeds. It will take both in your arsenal in order to combat and existing weed problem. Research pre-emergent herbicide in order to find out some basics about it.

I had to laugh when I saw this thread as I am in the same boat, and have mulch! A fabric weed 'barrier' was also layed, but I had grandson remove it since the weeds came right thru. In the area along the fence I have trees and bushes, and i'm in the process of hiring someone to come in and lay black plastic(heavy garbage bags cut open)and top with pea gravel. Weeds that pop up here and there can then be sprayed,and handled much easier. The idea of using all that weed killer mentioned above scares the bjesus out of me!

Since you already have the stone(the expensive part!)I would start laying the plastic, doing a section at a time. It will be very time consuming (kids/grandkids/neighborhood kids?), but a lot less costly than other alternatives. I wish I had that stone! ;)

It's a matter of something that isn't at all climate appropriate. Places where all that rock work are places where a lot of the weed control is done by controlling water, as in a desert. There aren't that many weeds that will grow without irrigation, so not irrigating that area solves the weed problem. In NJ, the only way to accomplish that is by putting on a roof, and even that may not work.

Yes, a lawn is going to be a lot easier, particularly since it can be done by checkbook. I'd ask in the lawn forum for advice on exactly how to get from the rock to grass, and explain that you aren't looking for anything wonderful. New grass does need to be watered, and that may be the real determinant of how much you can do at one time. After it is established, lawn is a xeriscape planting in the East. A minor technical detail that really needs to be better known. There are probably areas around the trees that are too shady for grass, and the rock may work there. Otherwise, Craig's List or an enterprising landscaper will probably disappear it for you.

Mad_g, you haven't seen my backyard! I haven't used the sprinkler system for the last 2 years, yet I have weeds almost all year long, and i'm in Austin where temps do drop. I'm trying to say this politely, but you are dead wrong re:irrigation and weeds. Starting in the spring, we've had rain almost nonstop. Last year we were in a drought condition, as was the year before(the year I had my backyard dug up). My yard doesn't know the difference, water or NO water. Any other suggestion would be appreciated by myself as well as marcj. :)

FYI, it will not solve weeds to use plastic bags below stones. Weeds will grow in silt that eventually accumulates on top. Roots will find ways to the soil below.

Marcj117 is there anything at all that you like about the rocks? Do you know what is underneath the rocks? I want to encourage you to at least remove some near the front of your house, but it will be time consuming and tedious. It took me around three days to move rock from one side of the yard to the other side of the yard (luckily it is not my yard). It was a small amount of rocks.

Around twenty years ago my neighbor decided to have a river rock yard with just a small area of grass. She also had a wonderful Cedar tree close to my property line. It all looked hideous so I won't go on about that. I wasn't watching the calendar so I do not know how many months passed before the weeds arrived. They just sprout above the plastic. She was long gone by then. The house has changed owners a few times since then. My current neighbor does not weed weekly. About every three months she and her family clean the area. It is not the weeds that are so messy, it is needles from the tree. The needles get stuck in the gaps between rocks. On my side under the tree there is an area too shady for most plants to grow. I keep it as an unplanted area. I rarely get weeds because I leave the needles on the ground. I am very grateful for the free mulch.

I would agree, advertise on Craigslist "free rocks - you haul" and then seed in the fall. If you were in CA, I would say the opposite.

You don't want to be spraying etc all year long and with the leaves from the trees....quite the clean up. Definitely lawn is a expense, but well worth it in my opinion and it can be organic if you so choose. There are soil, lawn care and organic lawn care forums. I would suggest reading their FAQ pages and seeing what style makes the most sense to you.