Will grass grow if you don't cover the seeds with anything?

Answer 1

Yes, with qualifiers. First, uncovered seed is attractive to birds which definitely will reduce germination. Second, the seed must be kept wet. Exposed seed will dry out very rapidly. So covering it with something like straw will help keep it from birds, help keep it moist and protect it from wind. A starter fertilizer should be used. Starter fertilizers have relatively high percentages of phosphorus. Normally phosphorous is probably not necessary in lawn fertilizer, but the little root foot of seeds have a lot of trouble extracting native phosphorus from the soil so making it available via fertilizer will help considerably in establishing the new seed bed.

Answer 2

This is a bit of a complicated question since it all depends on the grass type. However, as a rule, if you are seeding a typical lawn (ryegrass, bluegrass, fescues) you can cover it with about 1/8" of soil. This will act as a mild protection from traffic, wind and from drying out or burning in the sun.

The #1 most important factor for germination is soil to seed contact. Soil holds the moisture and nutrients that the grass needs to grow. When grass is still a seed, it has no way to "reach out" for nutrients and moisture (in other words it doesnt have roots or leaves yet!) so these necessary inputs need to be physically touching the seed.

The reason you dont want to plant the seed too DEEP, is because the plant requires light too! Inside of the seed is a carbohydrate rich material called the Endosperm. This substance contains enough energy for the plant to break the seed coat, send out the first root and the first leaf. But there is a limit to how long these tissues can grow before the seed runs out of energy. After that the plant must aquire energy from its environment.

Another alternative to covering the seed with soil is to use burlap. Prepare the seedbed first, then spread the seed on the surface. Pack the seed gently into the soil with either your foot or a lawn roller. Then cover the seed using burlap (available at any nursery or greenhouse). The burlap will protect the fragile seed from the sun while holding the moisture close to the soil. It will also allow some light in so the leaf can capture the sun as soon as it emerges.

Hope this helps, happy planting!