Should you seed or fertilize first in spring? Expert advice for luscious lawns

Which order is best? Get it right with these tips

lawn fertilizer
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Q:  Spring is on the horizon and I want to prepare my lawn for the warmer months ahead. I plan to over-seed the bare patches with a cool-season grass. I also want to apply a fertilizer to give it a boost and get it looking really green and lush. However, I'm not sure whether to sow seed or fertilize first. Does it matter, and if so, which order is best?

A: Both of these lawn care tasks are great for getting a lawn back into shape after inclement winter weather, but the order in which you do them can make a difference to the results. As you are sowing in early spring, it's generally advised to plant the grass seed first, then apply a regular lawn fertilizer a few weeks afterward. 'The reason being is that the new grass seeds are very delicate and could be damaged by the ingredients in the fertilizer,' explains lawn care expert Gene Caballero of GreenPal. 

'By seeding first, the grass seeds can become established and develop a strong root system as a foundation. Once the seeds are showing good, strong growth, you can then add fertilizers for your particular grass and soil type.'

Gene Caballero
Gene Caballero

Gene Caballero is the Co-Founder of GreenPal which has been described as Uber for lawn care. He has been in the landscaping business for over 25 years.

hand on grass

Fertilizing at the right time will give your lawn a boost

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Chris Brininstool from LawnStarter agrees: after germination is established (around 4-6 weeks), you can apply a round of nutrient-rich lawn fertilizer, he says. 

Aerating before you sow the grass seed is beneficial for success, and will help the fertilizer, when you apply it, penetrate down to the roots more thoroughly. 

To get rid of lawn weeds, you may also wish to apply a herbicide when you fertilize the grass. But, to avoid damaging your new seedlings, be sure to check the label first. It should tell you how long you need to wait to apply it after sowing fresh seed.

hand holding grass seed

If sowing grass seed in early spring, wait a few weeks before applying a general fertilizer

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Are there any exceptions?

An exception to this guidance is if you plan to use a dedicated starter fertilizer, says Chris Brininstool. These should be applied when you plant your grass seed (either just before or just after) – it will help speed up the germination process, he explains. This is due to the high concentration of phosphorus they include. 

A well-rated example is Scotts Turf Builder Starter Food, available from Amazon, which can be applied immediately before or after sowing grass seed. Pennington UltraGreen Starter Lawn Fertilizer, also from Amazon, is another option, and includes 5% iron to encourage a deep green lawn. It should be applied evenly just before sowing your grass seed, then watered in well. Both products can also be used when planting sod.

According to Anton Schwarz, the CEO of Lawn Liberty, the situation also changes if you are sowing warm-season grasses to repair patches in your lawn, like Bermuda grass and Zoysia grass. These are the grasses that are better suited to hotter climates in southern states. 

While cool-season grasses (such as Kentucky bluegrass and fescue – better suited to northern states) tend to do best when seeded in the fall or early spring, warm-season varieties are best sown later, in late spring or early summer.

Anton Schwarz
Anton Schwarz

Anton Schwarz is a seasoned lawn care professional who started his own business to meet the need for high-quality lawn care services around Madison County, AL. He provides a range of services and uses eco-friendly products whenever possible. Anton also runs, an info blog that covers a wide range of topics related to lawn care. His blog has become a go-to resource for homeowners and other lawn care professionals who want to stay up-to-date on the latest trends and techniques in the industry. 

'Fertilizing should come first in this case,' Anton continues. 'Applying a slow-release fertilizer in the early spring, when the soil has warmed up, can help get your lawn off to a good start. It's best to wait a few weeks after fertilizing before seeding, to allow the fertilizer to fully penetrate the soil and avoid the risk of burning the new grass.'

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Holly Crossley
Freelance Gardening Writer

The garden was always a big part of Holly's life growing up, as was the surrounding New Forest where she lived. Her appreciation for the great outdoors has only grown since then; over the years, she's been an allotment keeper, a professional gardener, and a botanical illustrator. Having worked for for two years, Holly now regularly writes about plants and outdoor living for Homes & Gardens.