One thing that struck me is the relative scarcity of earthworms in both the garden and lawn areas. Part of the issue is apt to be former management practice: For probably the past twenty or more years the yard was cared for by a commercial "mow and blow" firm. In digging in both flowerbeds and the lawn itself earthworms are seen, but rarely; maybe one every second or third shovelfull of dirt.
At the same time, there seem to be lots of snail, slugs, sowbugs and outdoor cockroaches. This implies that there's enough moisture and food to support detritivores in some numbers.
I've switched to mowing the lawn without a grass catcher and raking at least some of the fall leaves into the flowerbeds to suppress weeds. Two years on, the earthworm population hasn't changed much. Far as I know nobody has used pesticide sprays in years, I used a little Sluggo until learning that it's bad for earthworms last year.
The present drought has persuaded me to replace all the sprinklers with drip irrigation. It's certainly more efficient than sprinklers and cheaper than relandscaping.
Drip irrigating the lawn has required about 1800 feet of Netafim Techline CV dripline. For now it's just stapled to the surface as I shift it around to match the water supply to the sun load. It's possible to mow over it, very carefully, with a reel mower.
Once the position is set, it'll be time to hide it. Trenching it in is one option, but that's a lot of work. According to Darwin's book on earthworms, they'll raise the soil level an inch in about five years under ideal conditions. I have the time, but it does not look like I have the earthworms 8-)
One approach is to simply wait and see if the population increases, but the fact it hasn't changed much in two years bodes ill for that notion. Some sort of nightcrawler seems like the best bet, but what kind and what stocking density are absolutely unclear to me. Alternatively, maybe something else is wrong and adding new species won't help at all.
Thanks for reading, any thoughts appreciated!