Will fertilizer burn new grass seed?

Author: Prof. Roger Hermiston  |  Last update: Thursday, May 29, 2025

As a rule of thumb, apply fertilizer at a rate of 0.5 to 1 pound of nitrogen is per 1,000 square feet. Don't overfertilize. Overdoing it can cause nitrogen burn and be detrimental to your grass seedlings. There are two types of starter fertilizers: granular and liquid fertilizers.

Will fertilizer hurt new grass seed?

A newly-seeded lawn is a mature lawn so it needs “regular” fertilizer, not starter fertilizer. The latter, wrongly applied, could end up burning your roots.

Can you burn grass seed with fertilizer?

Using inappropriate fertilizer products.

Herbicide-containing weed & feeds or crabgrass preventers designed for established lawns may burn or otherwise harm germinating seed and seedlings.

Can you lay grass seed and fertilizer at the same time?

For the fertilizer to be effective and not harm the grass seeds, you shouldn't fertilize and seed at the same time. You need to wait until the seeds begin to sprout, which usually takes about six to eight weeks.

How soon after seeding can I fertilize?

How long after reseeding or overseeding my lawn should I wait before fertilizing? Your best bet is to fertilize your newly seeded or overseeded lawn with Scotts® Turf Builder® Starter® Food for New Grass directly after seeding. Then, you need to wait 6 to 8 weeks before fertilizing again.

When to FERTILIZE NEW Grass Seed | Carbon X, Milorganite, Bio-Stimulants, GreenePunch

Do you put grass seed or fertilizer down first?

You want to fertilize new lawns six to eight weeks before laying seed. The type of grass will determine when you want to lay fertilizer and seed. For example, cool-season grasses are sown during the fall, so you should put down fertilizer in late summer or early fall.

Can you put fertilizer on top of seeds?

While it might be tempting to fertilize your lawn right after sowing new seeds, it's wise to keep these two tasks separate. Seeds and young sprouts are much more fragile compared to fully established turf, and fertilizer treatments could be too strong for their delicate growth.

Should I put topsoil over grass seed?

Grass seeds do need some light to germinate, so burying them too deep under topsoil can inhibit growth. However, a very thin layer of topsoil (one-quarter inch or less) over the seeds is actually beneficial to retain moisture and improve germination.

How often should I water new grass seed?

With new grass seed, maintaining consistent soil moisture is key. Professionals know how to avoid waterlogging while keeping the soil hydrated. They will water 2-3 times daily in short intervals to prevent oversaturation, ensuring about 3-4 inches of water per week.

Do seeds germinate faster if fertilizer is applied?

No, seeds do not germinate faster with fertilizer than without. The seeds do not actually need fertilizer for the first few weeks of their life. It would be a seed sowing mistake to feed too early as germination can actually be hindered if there is too much fertilizer in the soil.

Will grass come back after fertilizer burn?

Healthy grass can bounce back with the right care. You'll want to make sure the grass is still alive before attempting to revive it. Usually, yellow and brown streaks can recover. But crunchy, brown grass could mean you need to consider replanting.

How fast does grass grow after germination?

Whether you're repairing bare spots, overseeding an existing lawn or starting from scratch, you can generally expect grass seedlings to emerge within seven to 21 days when grown under proper conditions. It may take another three to four weeks of growth before grass is long enough to mow.

Can you put Scotts fertilizer on new grass seed?

Scotts® Turf Builder® Starter® Food for New Grass is safe to use on any grass type. It can be applied immediately before or after planting grass. We recommend using a Scotts® spreader to apply this product.

Can I just sprinkle fertilizer on top of soil?

A: DO NOT SPRINKLE the granules directly onto the soil!!!. It will burn and kill your surface roots. Use as directed or buy a sprinkle alternative.

What happens if you mow over new grass seed?

Mechanical damage is also a risk. Foot traffic and driving a heavy lawn mower across a newly seeded lawn can wreak the fragile new grass. You risk: Compacting the soil and blocking sprouts from popping up.

Can I just throw grass seed on bare spots?

Very Small Patchy Areas: For tiny bare spots (think a few inches in diameter), throwing a small amount of seed and keeping the area moist might suffice. However, even in these cases, lightly raking the soil to create some seed-to-soil contact can significantly improve results.

What is best to cover new grass seed?

Covering with polythene sheeting is a must on slopes!

It's the best protection and insurance for your seed and hard work.

Does grass seed need to be raked in?

While you don't want to bury the seeds deeply, they do need good soil contact. Use the back of a plastic leaf rake to gently work the seeds into the top 1/8 inch of soil. Make short, light strokes to avoid redistributing the seeds unevenly.

Can fertilizer damage seeds?

Fertilizers can damage the seed in two ways. The first, and most serious, way that fertilizers damage the seed is by specific toxicity. For most N fertilizers, ammonia (NH3) toxicity is the largest factor that causes seed damage. The second way is by salt damage.

What fertilizer is safe for new grass seed?

As we mentioned earlier, the right fertilizer for you may differ depending on your soil results. In most cases, however, a high-phosphorus starter fertilizer like 10-10-10, 20-10-10, or 16-8-8 should do the trick. Whatever you decide, make sure the product you're using is suitable for the type of grass you're planting.

Can I grass seed and fertilize at the same time?

Fertilizing and overseeding at the same time is generally recommended, but waiting until the seeds are well established can have better results. After overseeding and fertilizing you will obtain a dense and beautiful lawn. If you need help taking care of it, call a lawn care professional.

How soon after planting can I fertilize?

Since survival will not be improved, growth increases are unlikely (except in very poor soils), and the potential for fertilizer burn is real, it might be best to make the first fertilizer application at least a few months to a year after planting.

How long does fertilizer last in soil?

Fertilizers for flowers will last in the soil for 2 to 4 weeks but depends on above mentioned conditions. The type of fertilizer you use will determine how long it takes for it to work in the grass. A little but continuous amount of nutrients are delivered over a 6 to 8 week period using slow-release fertilizers.

Should I water after seeding and fertilizing?

Watering is critical to successful lawn establishment. Once wet and seed germination has begun do not let the seed dry out. Postpone reseeding an area during a drought if irrigation cannot be provided. A newly seeded lawn requires daily watering during dry periods.

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