How Long Does it Take Grass Seed to Grow?

After spreading grass seeds, whether it’s overseeding a damaged lawn or establishing a new lawn, the first question that comes to mind is how long does it take grass seed to grow? 

Well, the answer depends on several factors such as the type of grass seed and soil, weather, watering or rainfall, the right amount of sunlight, and other lawn care practices. 

But one thing’s for sure, starting from seed doesn’t provide you with immediate gratification so if you’re looking for overnight results, sod may be a better yet much more expensive option. Here’s a list of different types of sod available.

To give you a rough idea, most types of grass seed take roughly 5 to 10 days to germinate but some may take up to 30 days depending on the grass species, weather, time of year, and soil moisture. 

Type of Grass – Seed Type Matters 

When it comes to grass seed growth from scratch, the first, and perhaps one of the biggest factors that come into play is the type of grass seed, and here you have two options warm-season grass or cool-season grass like Kentucky bluegrass and ryegrass. Did you know that Kentucky bluegrass is the most commercially valued turfgrass in America?

Regardless of whether you’re spreading warm-season or cool-season seed, a solid rule of thumb for germination time is between 1 and 3 weeks. 

How Long Does It Take Cool-Season Grass To Grow?

Cool-season grasses such as tall fescue take longer to grow than warm-season grasses and grow best when the soil temperature is between 50 and 65 degrees Fahrenheit. 

With proper care, the germination process of cool-season grasses starting from seed to lawn is approximately 30 days.

To give you a few examples:

• Annual ryegrass or perennial ryegrass takes 5 to 10 days to germinate,
• Kentucky bluegrass takes 7 – 10 days to germinate,
• Tall fescue takes roughly 7 – 12 days to germinate. 

How Long Does It Take Warm-Season Grass To Grow?

Warm-season grasses tend to take longer to germinate than cool-season grasses, owing to their deeper root systems. Adding to this, warm-season grasses desire hot weather, so cold winter temperatures can hinder their germination process and possibly kill young grass plants. 

Warm-season grasses prefer a soil temperature between 60 and 75 degrees Fahrenheit and daytime temperatures that are consistently above 80 degrees Fahrenheit for the fastest germination time.

Bermudagrass is the fastest-germinating warm-season grass.

For example:

• Bermudagrass is germinating in as little as 10 days,
• Zoysia grass takes between 14 and 21 days to germinate,
• Centipede grass takes between 14 and 21 days to germinate,
• Buffalo grass takes between 14 and 30 days to germinate. 

Age of the Seed 

Most people buy grass seed at their local garden center but what they overlook is the tested date and germination rate labeled on the package. 

You can expect to achieve this germination rate when you use the grass seed within the 1st year post-packaging.

After the 1st year, the seed quality begins to deteriorate even when stored under the right conditions, and in terms of numbers that works out to a decrease of 10% to 20% for each subsequent year of storage. Here are some tips on maintaining grass seed viability in storage.

The type of storage also affects the seed’s germination rate and longevity, where bagged seeds are quickly affected by humid weather conditions, and seeds placed into sealed containers right after harvesting offer longer viability. 

However, seeds that are stored for a longer period aren’t bad but will take longer to germinate. 

Preparing the Soil Before Planting 

Grass seeds will germinate in any soil condition, but the germination rate will depend on how well you prepare the soil. There are certain steps to build a solid foundation for new grass seed, starting with removing old turf, plants, and weeds.

Weed Control

You can apply Glyphosate-based weed control products to kill any existing weeds in your lawn but take note that you will have to wait approximately 2 – 3 weeks after application before planting new grass seeds. 

Rotavate the Soil

The next task is to rotavate the soil, meaning turning the soil over with either a gardening fork, spade, or mechanical rotavator.

Rotavating is an essential step in preparing the area being seeded, after which let the ground settle over the next few days, and fill any new holes if they appear with topsoil. 

Soil Testing

Testing soil pH is another important part of soil preparation to help determine how acidic or alkaline the soil is.

Grass seed germinates at a pH range between 5 and 8, so you will have to adjust the soil pH accordingly. You can add lime to raise pH levels and organic matter such as a layer of compost to lower pH levels. 

Watering

To make the soil more hospitable for new grass seeds, maintain moist soil by watering it for a few days before spreading any type of seeds. Keeping the soil moist will accelerate germination time and provide immediate moisture to emerging roots. 

Fertilization

This is the right time to apply the first round of starter fertilizers such as Scotts Turf Builder. This starter fertilizer helps improve seeding results and is safe to use for any type of soil or seed. 

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Seeding

Once you’ve got the right amount of grass seed for your square footage of the area, you can spread them with your hand but it’s best to use a hand spreader or drop spreader for even lawn coverage. 

It’s very easy to get carried away and put down too much seed or conversely, not enough seed, which will result in the grass seed out-competing each other. 

After spreading grass seeds, cover them immediately with straw (not hay), mushroom soil, or screened compost to protect them from birds and other pests. 

These products serve as soil amendments as they break down and improve your soil’s fertility and structure. 

What is the Best Temperature to Plant Grass Seed?

The best temperature to plant grass seed for it to germinate depends on the type of grass:

• Cool-season grasses require a soil temperature of 50–65℉ (10–18℃)
• Warm-season grasses require a soil temperature between 65–70℉ (18–21℃).

If you aren’t aware of your current soil temperature, you can use a soil temperature map to determine whether or not it’s the right time to seed your lawn. If the temperatures aren’t right for the particular type of grass, germination may fail and the grass won’t grow. 

Adding to this, good soil contact is also required for successful germination because only when the seeds warm up correctly will they be able to get the right amount of moisture to swell and sprout. 

How Much Sunlight Does Grass Seed Need for the Growth Process? 

Most types of grass seed need approximately 4 to 6 hours of direct sunlight to germinate. Some lawns get full sun (8+ hours of direct sun) while others medium or moderate shade (4 – 6 hours of direct daily sun). 

Grass seeds always prefer more sun, but if your lawn has a mix of sunny to medium shade areas, then you should choose compatible lawn grasses.

If your lawn is in a shady spot, choose specialized shade-tolerant cool-season grass blends such as rye and tall fescues and warm-season grass like St. Augustine and Zoysia. 

How to Water New Grass Seed? 

Watering new grass seed for germination and to grow into a green lawn may seem easy, but there’s a lot more thought and effort that goes into it.

When watering seeds of any grass type, there are two things to always remember:

1. Not applying enough water will kill the sprout, and
2. Too much water can leave you with less than desirable-results. 

For grass seed germination, it’s highly important to keep the grass seed moist all the time. This can prove to be a complicated task given the many factors that make every grass-growing situation unique but here are some tips to help your grass seeds germinate correctly. 

The goal of watering isn’t just throwing a ton of water per week on new grass seeds or better yet turning the sprinkler on at certain times per day. Watering new grass seeds can put you at risk of a mess for three different reasons:

1. Seeds can get floated or washed away into clumps and bare spots;
2. Seeds can stick to muddy shoes when you move hose-end sprinklers or a cheap lawn sprinkler;
3. Sinking soil can leave a trail of footprints across your lawn;

The key is to find the right balance between the amount and frequency that suits your soil, weather conditions, and equipment (sprinkler). 

However, all types of grass seeds need moisture and a certain temperature range to germinate. Once the germination process has kicked off, if conditions change, the seed or new sprout is vulnerable and can die. 

If you don’t provide an adequate amount of water or there wasn’t the forecasted sufficient rainfall in your area when you were away, the seed or sprout dries out and dies. 

This is why it’s important to provide an adequate amount of water at all times. Once the grass seed germinates, the roots start growing into the soil and leverage the soil moisture below ground so they aren’t so vulnerable now. 

Here are some simple steps for the ideal watering schedule:

• Grass seeds should be watered daily for moisture retention and germination. Refrain from watering grass seeds directly before or after a storm. 
• The best time to water new grass seed is in the morning. Do not water past sunset because wet soil overnight can lead to fungal infections. 
• For a lush lawn, water grass seeds frequently but with small amounts of water. Keep the top two inches of soil moist but not soggy, which you can achieve with 5 – 10 minutes of watering. 
• Hold the water hose at an angle and spray water above the seeds and not directly onto the seeds as it could wash them away. 

When to Fertilize New Grass Seed? 

Fertilizer plays a pivotal role in the health of your new shoots. Assuming that you’ve already applied a starter fertilizer when prepping the lawn for new grass seeds, the next round should be a regular fertilizer application that should be applied roughly 4 to 8 weeks after the first starter application. 

Most lawns ideally need 1 – 2 fertilizer applications per year but could be more depending on the health of your lawn. 

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Still curious? Click here to learn about the best time to fertilize new grass seed and the need to fertilize your lawn every year.

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Along with adding regular fertilizers after a few weeks of growth or approximately 14-30 days, check to ensure the acidic levels are in check.

If your soil test reveals that your soil is too acidic, consider adding lime such as dolomite lime because it contains the most magnesium. 

When spreading new grass seeds, you can also topdress the lawn with compost to encourage growth. Compost serves as a soil conditioning agent and paves the way for healthier, thicker grass. 

When to Mow a Lawn from Seed? 

Regardless of the type of seed, you sow or whether it’s a warm-season lawn or cool-season lawn, letting your grass grow to the right height before cutting it with a mower blade is important.

If you mow too short, your lawn may never grow back properly and will not result in a healthy lawn or perfect lawn. 

The ideal height for your grass in an established lawn should be between 5 cm to 7 cm before you cut it. At this height, the grass has already developed strong roots and is a few inches tall, so it won’t be stressed when you mow it. 

The ideal conditions to mow your lawn are the middle of the morning when the grass is dry or late afternoon after 4:00 p.m. 

Check out my detailed article on when to mow new grass.

Final Thoughts

The amount of time it takes for grass seed to turn into grass seedlings depends on several factors including the type of grass seed, soil temperatures when you plant grass seeds (weather), and the nutrients you provide. 

Most grass seeds germinate and grow within 10 – 14 days but sometimes can take up to 30 days. It may seem that it’s taking forever for new grass seeds to grow after planting grass seed, but as the saying goes “good things come to those who wait”.