Hi Barryjnr,
If you can take some pics that would be great. It can be really frustrating trying to get it right, sorry if I'm asking too many questions here but I'll try and cover the most common things first.
20mm is a good height to mow couch and mowing once a week should be fine. When you say it's an off colour like it's been cut too short, does it appear scalped? Is the colour uniform across the length of the leaf or is it only the tips? How is the thatch buildup?
When you water, do you give it a deep watering or a short water by hand?
I've used Munns golf course green myself and I've been quite happy with it. Have you checked the ph level of your soil? Most Australian soils tend to be a little acidic and as a result the lawn will have trouble absorbing the nutrients in the fertiliser. If the ph is somewhere between 5.5 - 7.5 it's fine, otherwise you may need to add some lime or iron sulphate to correct the soil.
When you top dressed, was the mix very finely screened? I use washed river sand and it's always gone down beautifully flat with a leveller, just like a billiard table. I once bought a bag of top dressing soil from the hardware store however, and it was absolutely terrible. It had small stones, bits of bark and even a piece of broken glass in it, though it was specifically sold as lawn top dressing.
Also, is your lawn in direct sunlight or does it get partial shade or full shade?
As for the bowling green.. a true bowling green finish is almost impossible to get at home as the maintenance and equipment required is extensive. Golf greens aren't normally of a bowling green standard and even they are hard to achieve at home. Top golf greens are often dug out and lined with plastic, have special drainage installed, then gravel and a sterile sand medium is put down. The greens are contoured to allow perfect run off and they're usually placed to get good sunlight, especially in the morning and good airflow across the surface. So obviously if you're getting close to a greens appearance you're already doing well and I wouldn't stress too much
Michael
