Generally speaking, you feed in early spring and late summer, so now is a good time.
The chemical fertilizers that you are talking about, is more 'fast food' versions of nutrition for lawns. It may have the technically correct ratio of nutrients to give a lush look but it isn't necessarily a good thing long term.
My approximate schedule is:
Early spring - thin layer of compost (basically really well aged cow manure) and some blood and bone over the whole lawn. With some decent rains and hot weather, it gets covered within a fortnight.
Late spring/early summer - Rooster Booster which is a pelletized form of chicken manure without the stink or burn. It is high in nitrogen so gives the lush green grown.
Late summer - a slow release lawn fertilizer. The one we use is a professional blend so I'm not sure if it easily available. It has a relatively low nitrogen content, and relatively high potassium level which helps to encourage strong roots and rhizomes for winter dormancy. Be careful of some of the name brand slow release fertilizers that are designed for early spring use with high nitrogen levels.
For our general lawn, we cut them fairly high for 2 main reasons. The theory is, the longer the grass blade, the longer the roots. This means it is drought hardier because it can tolerate longer periods without water or having the roots burn. It also helps to shade and protect the roots from the sun. It took me a while to convince my husband to do this but he is now a convert.
We also have a mower that essentially mulches the clippings. We don't collect the clippings and bin them elsewhere. It goes back on the lawn as a fine mulch each time it is mowed.
We also mow on an as needed basis. In summer, it can be twice a week and in winter it can be several weeks without mowing. The point is to never take too much off at once so that the grass gets scalped or burnt from the sudden sun.
I know this seems like a lot, but it really isn't that much work with the right equipment, a bit of a schedule and know how.
We also have some sections of pristine cylinder mowed turf. It started because DH wanted his own putting green and we are now turfing another section that can become a grass tennis court.
In the future, I would like to turf another section of our yard in Empire grass as part of the children's play equipment area. Yes, we are a lawn mad family LOL.
A warning with the weed'n'feed, if you have a broad leaf lawn, it will kill your lawn too. If you need to weed and it is too large a section by hand (or chook), then get a specific herbicide for that weed and spot treat. Anything multipurpose (w'n'f) will have compromises.
Oh, regarding watering, 2 sections of our lawn gets recycled septic water and the rest of the yard relies on natural rainfall. With healthy soil and the right lawn choice, we don't need to artificially water any of our lawn areas and it looks green year around. We went through the drought with lush lawns to the point where the Council sent inspectors around to check on our water usage after someone complained (we were on level 7 restrictions). We run our house predominantly on tank water and had minimal town water charges.
ETA I used to spray Seasol on it occasionally too. I haven't since I had #3 and didn't have time but I plan on getting back to it.
This post has been edited by *LucyE*: 21/11/2012, 06:24 PM