Establishing new sod and new seed

Everything else on this site says deep and infrequent.  New sod is the exception, and the reason is simple: it has no roots in the ground yet, so it cannot reach anything below itself.

Until it roots, a piece of sod is a mat of grass sitting on soil, drawing water from the thin layer of its own root mass and nothing else.  That layer dries out in hours in July.  So new sod is kept damp - often more than once a day through hot weather - for the first couple of weeks.

Then the schedule changes, and this is the part people miss.  Once it has gripped, the watering is stretched out and deepened week by week until it is on the normal deep and infrequent pattern.  Staying on the establishment schedule for months produces exactly the shallow-rooted lawn the deep schedule exists to prevent.

Newly seeded areas follow the same principle for a different reason: a seedbed that dries out once at the wrong moment loses much of what germinated.  Consistent surface moisture through germination matters more than anything else you do.

Laying sod on compacted subsoil is money spent twice.  Preparation is the difference between a lawn that behaves for ten years and one that fights you from the first summer.

That last point catches people out.  If Bermuda is already in the ground and zoysia is going on top of it, the Bermuda comes back through the seams and you end up with two lawns competing rather than one.  How that is handled has real timing constraints attached and it is worth having somebody look at the site before anything is laid.

• Loosen the top few inches so roots have somewhere to go, rather than laying onto a pan
• Grade so water runs away from the house rather than sitting against it
• Clear debris, old roots and construction rubble.  It never gets easier to remove later
• Get a soil test in before anything goes on top.  See the soil testing guide
• Deal with the old lawn if the new grass is a different species.  Bermuda in particular will find its way up through almost anything

Three things go wrong often enough to be worth naming, and all three have straightforward answers.

Browning along the edges and seams is almost always drying out.  The cut edge of a piece of sod has the most exposed surface and the least contact with the soil below, so it dries first - particularly along paths, drives and on the sunny side of the lawn.  Pressing or rolling the seams improves the contact, and a little extra water along edges usually settles it.  Gaps between pieces make it considerably worse.

Water running off instead of soaking in is a clay and slope problem, and the fix is two shorter cycles half an hour apart rather than one long one.  If it still runs off, the soil underneath was probably not loosened before the sod went down.

Repairing bare spots in an established lawn starts somewhere else entirely: with why the spot is bare.  Shade, compaction, drainage, traffic and pet damage will all defeat a repair that does not address them.  Once the cause is dealt with, a running grass such as Bermuda will often close a small gap on its own with soil contact and water, and larger areas want sod, plugs or seed depending on the species.