Growing grass in the shade can be difficult because of the lack of light, reduced air circulation and increased ground moisture. In severely shaded areas, the lawn may grow in thin. Fescue has the best chance of growing well in the shade, but neither bluegrass nor ryegrass will do very well. Don't lay as much grass seed as you would in sunny areas. Grass seedlings cannot grow as closely together in the shade. Once the grass has established, mow the shady spots a bit higher than you would the sunny spots.
Loosen the soil with a garden rake. Choose fescue varieties, or mix bluegrass with fescue--two parts fescue to one part bluegrass.
Pour the grass seed in the hopper of a broadcast spreader. Read the application rates on the seed bag and adjust the dial on your spreader to 1/3 the amount indicated for a sunny area. Spread the seed by pushing the broadcast spreader across the area to be seeded until the entire area is covered with seed.
Rake the seeds lightly to bury them in the top layer of soil so they are no more than 1/4 inch deep when buried.
Water the grass daily to keep the seedbed moist. The duration and frequency will vary depending on local soil and weather conditions. If you notice puddling, cut back on the watering, and if you notice the soil drying out, increase the watering. Irrigate at this frequency until your first mowing, then back down to a regular watering schedule of a heavy soaking once per week during the summer. Back down further in the fall to a heavy soaking every 10 to 14 days. Aim to apply 1 inch of water at each soaking.
Cut the grass in the shady area a bit higher than normal. Mow it to 3 1/2 inches when it reaches 4 to 4 1/2 inches tall. This allows more surface area for photosynthesis to take place.
Overseed any bare areas from mid-August through mid-September. Loosen the soil with your garden rake. Sprinkle grass seed in the bare area at a rate of 16 to 22 seeds per square inch. Keep the soil moist until germination.