Lawn Recovery following Plumbing Related Trenching
Plumbers recently had to dig a 5' deep trench across my front lawn. There are two main issues: 1) The trench is mounded with clay on top and any topsoil removed. It has been three weeks and it's unclear if it is still settling. 2) The surrounding area is compressed from the heavy machinery operating on the soggy lawn, also has a layer of clay scattered throughout. The impacted area is roughly 800 sq ft. What can I do now and what has to wait until fall? What do I have to do to make the soil grow grass once more? While I'm not thrilled by my ugly lawn, I'm not opposed to waiting until fall if that's the smart thing to do in the long run. Thanks!
Howard County Maryland
There is nothing easy about this situation. If you have never tested the soil, results will give you pH, liming, and nutrient deficiencies. You can do this now in preparation for seeding http://extension.umd.edu/hgic/soils/soil-testing
You have to make some decisions. You can do the renovation now if you are able to keep the newly seeded lawn or sod watered all summer or wait until around Labor Day. This makes sense if you are worried about the ground settling.
If you renovate now you will have to wait until the area dries out so you do not make the soil compaction worse.
When the area drys out you can loosen the trench area with a hard rake, grade, and incorporate some organic matter and topsoil into the clay about 2-4 inches. Rake the area or lightly roll with a water filled roller.
For full sun to part shade sow a turf type tall fescue grass seed and cover lightly with straw. You will have to keep watered until it germinates and during dry periods in the summer. Most likely you will have a lot of weed seed germinating. You will have to overseed again in the fall.
Or If you wait to seed around Labor Day - Cover the bare areas with straw now to prevent erosion. Rake away the straw to renovate. After seeding you can lightly cover the seeded area with straw.
See our website and publications on lawn renovation and care and maintenance after seeding http://extension.umd.edu/hgic/lawns/lawn-renovation