[John T]

I have a customer who wants to install a putting green in their backyard. A retaining wall has already been installed as this area was originally going to be used for other purposes. I have no idea how the wall was installed and whether any geogrid was used. Any suggestions on base prep given the existing retaining wall? This will be my first putting green so any other advice is welcome as well.

(it is the area to the right in the pic)

[John T]

Here's another view of the area.

[skahuna]

as long as you dont undermine the wall or change the grade drastically i dont think a putting green will put anymore load on the wall than whats there now. if the soil is clay i would put some perf pipe at the low point of the dig and daylight it some where so water doesnt pond in the base.
a landscape designer i work with sells them and ive built a few with him prep is a lot like a paver patio get your grade apprx. with tamped modified then a couple of inches of screenings (stone dust) raked to your grade tamp that and then hand trowel everything (a 4' board helps to scree with) if your not a golfer get one to help you with hole placements and final grade. know where your holes are going from the start you'll need to put a clean stone pit under them so they dont puddle
the last couple we built were out of reinforced concrete im not sure what the advantage to this is other than its easier to edge the turf

[mdvaden]

Is this going to be a real putting green - bentgrass?

When I worked at country clubs, the bentgrass was sown on top of about 8" of blended soil. It was mainly sand.

About 90% sand / 10% organic matter, ranging from fine bark to compost or both.

Bentgrass has about 7,000,000 seeds per pound compared to Rye's about 300,000 per pound.

So a pound of bentgrass goes a long, long way.

You'll probably be aiming for about 16 to 24 seeds per square inch (or the recommended number of pounds per 1000 sq. ft.).

You will want a grid of drain lines under that green if possible.

You will need to tamp, rake, roll and repeat that many times. Because no settling of soil is acceptable on a golf green.

When turf is mowed at 1/8", there is no room for settled soil dips.

So, they will buy a real walk behind greens mower with a reel? Those start very easy, and I don't think it's too hard to get them. Same distributers that sell to golf courses.

I wrote a trivia topic on setting pins on golf greens. Nothing about soil, just the complexity of moving the holes and pins. If you're curious, my link is in my signature.

The pin-setting topic is available by selecting ADVICE then Advice page 1. It's somewhere in the list.

[John T]

Sorry I wasn't clear. No, this will not be a real green.