when do i cut my newly seeded grass?

Answer 1

When the blades are at least 1/8" in width.
Any sooner and you'll wind up ripping them from the ground.
The roots have not had enough time to anchor properly.
Cutting too soon also exposes the roots to this killing heat.

Answer 2

Assuming this is Kentucky Bluegrass, Fescues, Perennial Rye Grass or other northern varieties, you should wait until it is about 4 inches long, then cut it back to 3 inches and then resist the temptation to cut it lower after that. Keep letting it grow to 4 inches and then cut it to 3 inches. Keep the blade sharp. You will develop strong and long roots that will make your lawn very resistant to disease and insect infestation and you will save yourself a lot of watering chores in the future.

If you cut the lawn too low, it will immediately stop root growth and develop more leaf since it needs a certain amount of leaf for photosynthesis, and thus its food production.

If you let the lawn grow to 5 inches or more before cutting it, the grass will have developed extra sheaths on the bottom to support the weight. This is not a desirable situation since this will make a more brittle feel of the lawn to the foot and this plant will have a more difficult time surviving winter and summer stresses. And besides, if you let the lawn go six inches, the neighbours will wonder if you moved out.

Since most weed seeds need sunlight to germinate, you will also be keeping these weed seeds from developing into locationally challenged plants when you keep the lawn at three to four inches.

Answer 3

This is going to depend on the type of grass you have. Some grasses should be longer than others. Bermuda grass, for example, is perfectly happy being 1/2 " high, which might kill another type.

First make sure your mower blade is very sharp.
Cut new grass when it is over 4" tall. Do not cut it more than 1 inch at this time. Let it grow to 4 inches again and then cut it to 2 and 1/2" if you like, only cutting an inch on first pass, then cutting the rest of the way. This will prevent the mower blade from ripping any grass out.
New grass should be kept a little long, especially at the end of summer when temperatures are so high. This helps retain water for better root development.

Here is a site of grasses and their optimal heights:

http://www.lawncare.com/index.cfm/event/Article.Detail/documentId/0b7a5522a774c606b63a330ed34f2de7

Answer 4

I work in a garden centre and we recommend that you wait until your grass is at least 4 inches high...reason:: to let the root system fully develop before bothering and possibly damaging it

Answer 5

When it is 2-3 inches tall