Steps to Care For New Seed
This may be the most important step! With the first watering, make sure that you apply enough water to wet the soil down several inches. Apply the water gently so that you don’t wash the seed away or create puddles.
You may have to water several times in short intervals until the bed is thoroughly wet.
After the initial watering, water often enough to keep the top inch or so of the seedbed moist until the seed germinates. The seed only gets one chance and if they dry out, they will die.
The best time to water is between 6 -10 am. It's generally cooler, there is less wind, and this fits in with the lawns natural cycle.
When it's hot or windy and areas beside driveways, sidewalks, along buildings, and hardscapes all may need additional watering. However, make sure to not over water or water too late in the evening. Too much water causes the seed to rot.
Watch the color of the soil surface. As the soil dries, the surface becomes lighter in color. When you notice about half to two-thirds of the surface lightening up, it’s about time to water.
Caring for your new lawn after germination
As your new lawn starts to germinate (anywhere between 10 and 28 days depending on the grass), you can reduce watering. By reducing your watering to once or twice a week, and watering down 1-2 inches, you will promote good root growth. This is dependent on the weather; if there will be multiple days with lows above 70, see the high temp suggestion below.
When you have a pretty even ground cover of new seedlings, try skipping a day of watering and see what happens. Watch the grass carefully. If the color starts to go from bright green to dull gray green, the grass needs water. You may have to water some quick-to-dry areas with a handheld hose.
If the grass doesn’t dry out, keep stretching the intervals between watering until you’re on a schedule of once or twice a week, or as needed. When you do water, don’t forget to water deeply, getting the moisture down 6 to 8 inches.
You will need to mow the new lawn when it reaches 3 to 4 inches high, depending on the type of grass. Don't water the day before or day of mowing. This will help
Make sure not to have your mower set too low. It is always good to mow grass at 3 inches or higher to prevent it from drying out. This is especially true for your new lawn.
You also need to make your first application of fertilizer about 4 to 6 weeks after germination. Young seedlings have a hefty appetite, so don’t skip this important feeding.
It is very typical to have broadleaf weeds pop up in newly seeded areas. Whether it’s new soil or freshly cultivated soil, it is a prime target for blowing weed seeds to find a home.
Don’t worry too much about the weeds until the grass is about 8-10 weeks established. After that you can apply a weed and feed fertilizer or a systemic spray to take care of the broad leaf weeds.
Regular weed control and fertilizer applications as needed are recommended for a nice healthy lawn.
In Iowa, our grass is categorized as cool season grass. On years where we are having significant temperatures while trying to establish new grass, you may have to cool your soil. If the forecast is expecting to have nights where the low temperature won't fall below 70, especially multiple days in a row, you may have to cool your soil. This can be accomplished by watering the area around 6 pm for 15-20 minutes.