Buy too little seed and your lawn comes in thin and patchy. Buy too much and you waste money, and if you actually spread it all, you can smother the lawn you were trying to grow. The right amount is a simple calculation, and it takes about five minutes.
Here is the whole process: measure your lawn, pick the right seeding rate for your situation, and multiply. We will walk through each step, then show you where the shortcuts are.
Step 1: Measure Your Lawn
Seed is applied by the amount of ground it needs to cover, so everything starts with your square footage.
The simple way. Pace it off. An average adult stride is close to 3 feet. Walk the length of your lawn counting steps, do the same for the width, multiply each count by 3, then multiply length by width. A lawn that measures 20 paces by 15 paces is roughly 60 feet by 45 feet, or 2,700 square feet.
The precise way. Use the measuring tool in Google Maps or a similar satellite tool. Right click on a corner of your lawn, choose measure distance, and trace the outline. It will give you the area directly, and it handles odd shapes better than pacing.
Odd shapes. Break the lawn into rectangles, measure each, and add them up. For circles, multiply the radius by itself, then by 3.14. Do not forget to subtract big non-lawn areas like the driveway, large beds, or a shed.
When in doubt, round up slightly. A little extra seed for touch-ups beats coming up short in the back corner.
Step 2: New Lawn or Overseeding?
This is the biggest factor in how much seed you need, because the rates are very different.
Seeding a new lawn means starting from bare soil, whether it is new construction, a full renovation, or a section you have cleared. Bare soil needs full-rate seeding, since every plant in the finished lawn has to come from the seed you put down.
Overseeding means spreading seed over an existing lawn to thicken it. The established grass is doing part of the work already, so overseeding uses roughly half the new-lawn rate.
If your lawn is more bare dirt than grass, treat it as a new lawn. If it is a real lawn that has thinned, overseed.
Step 3: The Seeding Rate
Seeding rates are given in pounds of seed per 1,000 square feet. Every Blue Sky blend uses the same rate, so there is only one set of numbers to remember:
- New lawn: 5 pounds per 1,000 square feet
- Overseeding: 2.5 pounds per 1,000 square feet
One rate across the whole line means you can compare bags, plan a project, or switch blends without redoing any math. The rate is printed on every bag and built into our coverage calculator.
Step 4: Do the Math
Take your square footage, divide by 1,000, and multiply by the rate.
Example, new lawn. A 2,700 square foot bare yard at 5 pounds per 1,000 square feet: 2,700 divided by 1,000 is 2.7, times 5 is 13.5 pounds of seed. The 25 pound bag covers it with seed left over for touch-ups.
Example, overseeding. The same 2,700 square foot lawn at 2.5 pounds per 1,000 square feet: 2.7 times 2.5 is about 7 pounds. The 7 pound bag is the right buy, not the 25.
That second example is worth pausing on. Most people overseeding a typical suburban lawn need far less seed than they think.
Why More Is Not Better
It is tempting to double the rate for a thicker lawn faster. It does not work that way. Every seedling needs light, water, and soil nutrients, and seedlings planted too densely compete with each other, come up weak and spindly, and are far more prone to damping off and other seedling diseases. You end up with a worse lawn than the correct rate would have given you, and you paid extra for it.
Put down the recommended rate, keep the soil consistently moist until germination, and let density come from healthy plants rather than crowded ones.
The reverse is also true. Stretching a bag across too much area gives you a thin stand with bare soil between plants, and bare soil is an open invitation to weeds. If budget forces a choice, seed a smaller area at the full rate rather than the full area at half rate.
Matching the Number to a Bag
Blue Sky bags are sized by the lawns they cover, not by arbitrary weights. Here is the coverage for every size:
| Size | New lawn | Overseeding |
|---|---|---|
| 3 lb | 600 sq ft | 1,200 sq ft |
| 7 lb | 1,400 sq ft | 2,800 sq ft |
| 25 lb | 5,000 sq ft | 10,000 sq ft |
| 48 lb | 9,600 sq ft | 19,200 sq ft |
The same chart applies to every Blue Sky blend, so once you know your square footage, you know your bag. If your project falls between sizes, size up. Leftover seed stores well in a cool, dry place and is exactly what you want on hand for spot repairs next season.
For projects beyond the 48 pound bag, our bulk pricing scales with quantity, and the calculator on each product page will show your price and coverage in real time.
The Shortcut
If you would rather skip the math entirely, answer a few quick questions and we will tell you which blend fits your lawn and exactly how much of it you need.
The Year-Round Lawn Care Guide · How to Overseed an Existing Lawn · How to Read a Grass Seed Label