Asking how much is grass seed is just like asking how much a car costs. The answer? It depends. Not every seed of grass will grow and thrive in your lawn. Depending on the conditions a bag of grass seed can range from $30 to $100 for a 20 pound bag. However, more expensive doesn't always mean better. While there is a certain cost to a higher quality bag of grass seed there is no magic grass seed that grows green and full in every lawn. So lets spend a little time figuring out just what seed for which you need a price.
Lets think back to the car analogy. When I shop for a car there are three main qualifiers I use to narrow down the choices. Once I clear those qualifiers it all comes down to price and personal preference. My three qualifiers are: What is the weather likely to be year round, What are my driving habits, and What design style do I like. Choosing the right grass seed can be narrowed down by answering similar questions.
What is your climate: Lawn grass can be divided into two climates: warm and cool. A general rule of thumb to decide which your region falls into is to think of what defines your area, a brutal Summer heat or large Winter storms. Just like picking a Camaro for snowy roads is the wrong choice of car so is picking a warm climate seed to plant in Michigan. There's nothing saying you can't but there are more practical choices.
What will you be doing on your lawn: Lawns can mean different things to different people. For some it's a work of art or a display piece for their weekend work. For others it is a place for football games or a herd of dogs. There is nothing saying you can't have some of both. While a certain car might hold up better to hour-long commutes on the highway it doesn't mean it can't drive down to the corner store. However, it does benefit you to at least choose a primary use.
What do you want the lawn to look like: Now we come down to what makes you think "That is a beautiful lawn." Most of that comes from the thickness and size of the blades of grass as well as the color. A full looking lawn is likely composed of a more coarse type of grass while a soft grass gives a smoother appearance.
Grass Types and Prices
Grass seed is a hard product to be completely thorough with due to all the blends available that attempt to get the best of everything. Below is a chart of the most popular types of grass seed along with their climate, traffic ability, and cost.
In regards to St. Augustine grass, you can't really find it as seed. It is a very hard grass to cultivate and the seeds have a very low chance of actually taking root. It tends to be sold as either sod or grass plugs and usually only sold in certain seasons. You would need to ask a local lawn and garden store for pricing information.
The prices on this list are obviously not set in stone. You can very well find all of them for cheaper if you shop around or buy in larger quantities.
Why Are Some More Expensive?
Some grasses are more expensive than others for same reason a hand-crafted table costs more than one from Ikea. There is work involved in harvesting these seeds. Some grasses are heartier, easier to tend to and simpler to harvest than others. If more work goes into producing ten pounds of zoysia grass seed, than why shouldn't it cost more than fescue grass?
Now if you're wondering why one bag of zoysia grass is more expensive than another, than that is another thing entirely. There is bound to be some other substances in a ten pound bag of grass seeds. However, they are required by law to give estimated percentages of those substances. The following things are commonly found in a bag of grass seed: weed seeds, inert material like chaff, and other crops. When you harvest a field of grass you are bound to get a few other things mixed in no matter how diligent you are. One reason why one bag is more expensive than the other are smaller amounts of these materials.
For many grass seeds there are multiple options. This is akin to the same car having multiple models. One model is more expensive because it has a sunroof and On Star. Some grasses have just been cultivated to enhance certain features. So be sure to ask what grass you need before focusing on the question of how much is grass seed.