The Fastest Growing Grass Seed

When you’ve got bare patches, a new build garden, or a lawn that needs rescuing before summer, waiting weeks for grass to grow isn’t an option. You need the fastest growing grass seed you can get.

The good news: some grass varieties germinate in as little as 5 days. The key is knowing which types grow fastest and what conditions they need to perform.

Grass Seed Germination Times Compared

Not all grass seed is created equal. Here’s how the main UK lawn grass types compare for germination speed:

Perennial Ryegrass: 5 to 10 days. The fastest. This is the go-to grass for quick results. It germinates at relatively low soil temperatures (8 to 10°C) and establishes rapidly. Most fast-growing lawn mixes contain high percentages of perennial ryegrass.

Tall Fescue: 7 to 14 days. Reasonably quick and very drought-tolerant thanks to its deep root system. A good choice if you want speed plus resilience.

Fine Fescue: 10 to 14 days. Slightly slower because it needs warmer soil (10°C+) to get going. Worth the wait for shaded areas where it outperforms ryegrass.

Kentucky Bluegrass: 14 to 30 days. The slowest of the common lawn grasses. Beautiful once established, but not the choice when speed matters.

For the fastest results, look for seed mixes with 70 to 80% perennial ryegrass content. These combine speed with enough fescue to give the lawn a finer appearance once established. For a full comparison of all our grass seed options with a decision table to help you choose, see our best grass seed UK buyer guide.

What About Annual Ryegrass?

Annual ryegrass germinates even faster than perennial, sometimes in just 3 to 4 days. So why don’t we recommend it?

Because it dies after one season. Annual ryegrass is designed as a temporary cover crop, not a permanent lawn. You’ll get quick green coverage, but come winter it’ll die off and you’ll be back to bare soil.

Stick with perennial ryegrass for lawns. It germinates almost as fast and will last for years.

Germination vs Establishment: Know the Difference

Germination is when the seed first sprouts. You’ll see tiny green shoots emerging from the soil. But a few wispy seedlings doesn’t mean your lawn is ready.

Full establishment takes 6 to 8 weeks, regardless of how fast the seed germinates. During this time, the grass develops its root system, thickens up, and becomes strong enough to handle foot traffic and mowing.

So while fast-germinating seed gives you visible results sooner (and protects bare soil from erosion and weeds), you’ll still need patience before the lawn is truly usable.

How to Make Grass Seed Grow Faster

Even the fastest grass seed needs the right conditions. Here’s how to maximise germination speed:

Get the Soil Temperature Right

Grass seed won’t germinate in cold soil, no matter how good it is. Perennial ryegrass needs consistent soil temperatures of at least 8 to 10°C. In the UK, this typically means sowing from mid-spring onwards, usually April in the south, late April or May further north.

Don’t be fooled by a few warm days in March. Check the forecast for consistent warmth, and remember that soil temperature lags behind air temperature. For a complete month-by-month guide to spring lawn tasks including when to sow, see our spring lawn care checklist.

Prepare the Soil Properly

Seeds need good contact with soil to germinate. On compacted or debris-covered ground, they’ll sit on the surface and fail. Rake the area to loosen the top layer, remove dead grass and weeds, and create a fine, level surface for sowing.

For the best start, apply Pre-Seed Foundation Feed before sowing. Its high phosphorus formula promotes root development without the herbicide found in regular lawn feed, which would kill your new seedlings.

Keep Seeds Moist (But Not Waterlogged)

Drying out is the number one killer of grass seed. Once germination starts, the seed needs consistent moisture. Water lightly once or twice daily with a fine spray. You want the soil damp, not flooded.

Overwatering is almost as bad as underwatering. Waterlogged soil lacks oxygen and can cause seeds to rot before they sprout.

Protect from Birds

Birds love grass seed. A light covering of topsoil (about 5mm) or fine compost helps hide seeds and keeps them in contact with the soil. For larger areas, consider netting until germination is underway.

Don’t Bury Seeds Too Deep

Grass seed needs light to germinate. Buried more than 5 to 10mm deep, it won’t have the energy to push through to the surface. A light raking after sowing is all you need, or simply let rain and footfall work seeds into the soil naturally.

Why Is My Grass Seed Taking So Long?

If you’ve been waiting weeks with no sign of growth, something’s wrong. The most common causes:

Too cold. Soil temperature is the biggest factor. If you’ve sown too early in spring or during a cold snap, seeds will sit dormant until it warms up. They won’t die, they’re just waiting.

Too dry. Seeds that dry out during germination usually fail. Check daily and water if the surface looks dry.

Poor seed-to-soil contact. Seeds sitting on top of thatch, dead grass, or compacted soil won’t germinate well. Preparation matters.

Old or poor quality seed. Cheap seed often has low germination rates. Buy from reputable suppliers and check the date. Seed more than a year old may have reduced viability.

Birds ate it. If you didn’t cover the seed, birds may have had a feast. Check for signs of pecking and resow with protection if needed.

Best Fast-Growing Grass Seed for Different Situations

Speed isn’t everything. The fastest seed needs to suit your conditions too:

For patchy repairs: A high-ryegrass mix gives the quickest coverage. Match the seed type to your existing lawn if possible. See our guide on fixing bare patches for the full process.

For high-traffic areas: Perennial ryegrass is naturally hard-wearing as well as fast. Look for mixes designed for family lawns or sports use.

For shaded areas: Accept slightly slower germination and use a shade-tolerant mix with fine fescue. Fast seed that fails in shade is no use at all.

For a complete new lawn: Fast-germinating seed gets you green coverage quickly, protecting soil from erosion and weeds while the lawn establishes.

Browse our full grass seed range to find the right mix for your situation.

After Establishment: Keep It Growing Strong

Once your new grass is established (6 to 8 weeks after sowing), it’s time to start a proper feeding programme. A seasonal lawn treatment provides the nutrients your lawn needs to thicken up and stay healthy, while helping suppress weeds that compete with young grass. For hassle-free feeding all year round, the Year Round Bundle covers every seasonal feed in one box.

Frequently Asked Questions

What is the fastest growing grass seed?

Perennial ryegrass is the fastest, germinating in just 5 to 10 days under good conditions. Annual ryegrass is slightly faster (3 to 4 days) but dies after one season, making it unsuitable for permanent lawns. For quick results that last, choose a seed mix with high perennial ryegrass content.

How long until I have a full lawn?

Germination (first shoots appearing) takes 5 to 10 days with fast-growing seed. Full establishment, where the lawn is thick, rooted, and ready for normal use, takes 6 to 8 weeks. During this time, keep traffic to a minimum and continue watering regularly.

What temperature does grass seed need to germinate?

Perennial ryegrass germinates at soil temperatures of 8 to 10°C and above. Fine fescues need slightly warmer conditions at 10°C+. In the UK, this typically means sowing from mid-April onwards, though timing varies by region and weather conditions.

Is annual or perennial ryegrass better for lawns?

Perennial ryegrass. While annual ryegrass germinates faster, it dies after one growing season. Perennial ryegrass is almost as quick (5 to 10 days vs 3 to 4 days) and will last for years with proper care. Always check seed mix contents. Some cheap mixes include annual ryegrass as filler.

Why is my grass seed taking so long to grow?

The most common causes are: soil too cold (below 8°C), seed drying out during germination, poor seed-to-soil contact, old or low-quality seed, or birds eating the seed before it germinates. Check conditions and resow if necessary. Dormant seed that’s been waiting for warmth will often sprout once temperatures rise.

The Bottom Line

If speed is your priority, perennial ryegrass is the answer. It germinates in 5 to 10 days, establishes quickly, and is hard-wearing enough for most UK lawns. Look for seed mixes with 70%+ ryegrass content for the fastest visible results.

But remember: fast germination is just the start. Give your new grass 6 to 8 weeks to establish properly, keep it watered, and resist the urge to use the lawn too soon. A little patience now means a healthier, thicker lawn for years to come.

For more seeding tips and lawn care advice, visit our lawn care knowledge hub.