Question
I have a small 30 x 40 ft backyard (Southern NJ; zip=08110) that has several large trees along the long side of the area which gets morning sun then dappled sun/dense shade in the afternoon.

I just bought the home 2 years ago and the yard was bare dirt... not even weeds would grow. I thinned out some of the branches and started a tall fescue lawn in early April 2005. It was a slow start but looked nice until midsummer when contractors took over the yard for some home repairs and the heat took its toll. The grass died.

This year, I tried a Vigoro shade mix. It started faster and things looked promising again until mid July. I reacted a bit too slow to increased water need but I found that no matter how much I watered, the lawn was drying up.

I looked carefully at the pattern of dry, dead grass and found that it was worst close to the trees. I recall someone saying that even old trees have 85% of their roots in the top 18" of soil and came to the theory that the trees were sucking up all the water and the grass could not develop deep enough roots.

At this point, some parts of the lawn are BARE and other parts severly affected and about to give out altogether. Trees win by a knockout!

What to do? This is getting expensive and much too time consuming!!

More water? Increase water sooner in the summer season? Cut back more branches? Plant clover? Japanese rock garden?

Help!! Please.


Answer
I think you diagnosed the problem yourself.

The tree roots will compete with the grass for water and the roots will also help compact the soil which will make grass less able to compete.

Your best option is to loosen the top of the soil (roto tiller) mix in plenty of organic matter, such as compost, and then reseed.

The reason the Vigoro shade mix germinated fast was probably due to high levels of perennial ryegrass (will germinate fast in warm soil).

Tall fesuce is not a bad grass for conditions like yours. Otherwise, try a shade blend which is primarily based on FINE FESCUES (hard, chewing, creeping red) and Shade tolorant cultivars of Kentucky Bluegrass.

Make sure you keep the top 1" of soil consistently damp until seeds have germinated (sprouted).

Watering more in summer will likely not help with very hot temperatures and draught conditions. Not much you can do to prevent trees from taking up water. However, improving the quality of the soil will help. This is only a temporary solution, however, as the tree roots eventually will move into the soil.