When grass does not grow, the first thing to do is to find out why. If nothing grows, the soil may be contaminated with herbicides or other chemicals that prevent growth. If the soil is dry, rocky, infertile or hard-packed, this, too, can prevent grass growth. Trees that out-compete grass for light, water and nutrients or heavy foot traffic from people or animals are some other reasons for problematic grass growth.
Landscape soil may be contaminated by soil sterilants or other chemicals. If nothing is growing in the soil, perform a growth trial to see if the soil has been sterilized. Put samples of the soil in two pots, and mix activated charcoal with the soil in one pot and plant seeds. Water and care for the potted seeds for four weeks to see if anything grows. If not, plan on making that part of the yard a patio, or remove the soil and replace it. If something grows in the charcoal-treated pot but not the other, the growing area can be treated with charcoal to tie up the chemical.
Dry, rocky, hard-packed or infertile soil can also prevent lawn growth. It is possible to improve such soil, but it's much easier to plant ground covers that can tolerate difficult conditions. Plant grama or buffalo grass instead of traditional lawn grass. Bishop's weed, bearberry, dwarf bush honeysuckle or sedum ground covers grow in poor soil. Plan xeriscape plantings with gravel mulch where the soil is extremely poor.
Trees compete with grass for nutrients, water and light. The combination of shade and lack of water often makes it impossible to grow grass under trees. Some trees, like walnut, even release a poison from their roots that kills many other plants. Shade-loving ground covers are much better under trees than grass. These include English ivy, hostas, vinca minor, Japanese pachysandra, ferns and bracken.
People, pets or vehicles repeatedly walking or driving over grass can kill the lawn, especially if it is in poor soil or in the shade. Fence traffic out of the area or the ground using mulch or pavers. Often, ground covers like thyme, sedum or Irish moss can grow among the pavers to soften the look.