What is the recommended fertilizer ratio (i.e. 10-10-10, 20-0-5, etc.) for...

Asked August 14, 2014, 7:24 PM EDT

What is the recommended fertilizer ratio (i.e. 10-10-10, 20-0-5, etc.) for starting a new lawn in raw soil? Soil was tested to be sufficient in phosphorus (75ppm), but low in lime (4.4), potassium (41ppm), calcium (343ppm), and magnesium (43ppm). I want to start the seeding process in early September, with a standard mix of bluegrass, fescue and rye.

Charles County Maryland soil soil testing lime lawn soil test

1 Response

There is no standard fertilizer for starting a new lawn because it needs to be based on a soil test. A "starter" fertilizer had phosphorus in it, but that isn't needed for your soil anyway.

Soil test results normally come with a fertilizer recommendation. Check the report you got back from the lab. It should give you some recommendations.

Your biggest problem is the low pH of 4.4. When pH is too low, the soil can have perfect levels of nutrients but not be able to utilize them. So, first order of business is to raise to pH to about 6.5. You'll need to apply about 165 lbs of lime per thousand square feet (assuming your soil is an average loam.) Use dolamitic lime, this will take care of the magnesium deficiency. This seems like a tremendous amount of lime, but when worked in it is manageable.

When you need to apply over 70 lbs. of lime per thousand square feet, half should be plowed into the soil and the remaining half should be raked or disked in.

We recommend seeding with primarily tall type turf fescue. Some bluegrass is okay to help get it established, but it will eventually die out. We do not recommend rye at all. This is assuming you have a sunny lawn or no more than part shade.

Please read over our website's publication on growing a successful lawn: http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG102%20Lawn%20Estab...

There are many other factsheets that are helpful: http://extension.umd.edu/hgic/information-library/home-and-garden-information-center-publications#la...

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