Question
Hello,

I抳e begun to renovate part (about 1/3) of my lawn, which is tall fescue in predominantly clay soil.  I recently received my soil test results from the N.C. Department of Agriculture (samples were taken from both the area to be renovated and the area that will not be renovated).  The test results recommended 20lbs of 5-10-5 fertilizer per 1000 sq ft (or equivalent ratio), which I gather from the websites of several states?agricultural extension offices is a fairly common grade recommendation.

My questions:

1.  The recommended grade/ratio seems outside the range of most of the fertilizer products I抳e seen for sale to the consumer.  A casual perusal at my local Lowe抯, Ace Hardware, and on the Internet revealed no lawn fertilizer brand geared toward the homeowner with a 5-10-5 analysis or any other 1:2:1 ratio for that matter.  For example, none of Scotts抯 products has anything close to this ratio.  The closest I抳e found thus far from any brand is a 1:1:1 ratio.  (Admittedly, I have not yet checked my local lawn & garden centers, which may have less well-known brands and less common grades.)  I抎 like to stick with a brand I feel I can trust, but it also seems I should adhere as closely as possible to the recommendations from my soil test report.  Are 1:2:1 ratio fertilizers really that difficult to find?  How important is it to follow the ratio recommended in the soil test report?

2.  My understanding is that phosphorus is more important than nitrogen for new and to-be-renovated lawns.  Given that I抦 renovating only part of my lawn, should I use two different fertilizers for my fall application?one higher in phosphorus than nitrogen for the sections I抦 renovating (which are clumped in several different areas) and a different fertilizer for the remainder of the lawn?  Is it worth the complication?  

3.  At least one source I抳e consulted?The Perfect North Carolina Lawn (Cool Springs Press, 2002) by Steve Dobbs?says that fertilizer for new and to-be-renovated lawns should not exceed 10% nitrogen because a higher percentage could burn newly emerging seedlings.  And yet, practically all 搒tarter?fertilizers I抳e seen for sale have 20% or more nitrogen.  (For example, Scotts抯 Starter Fertilizer has 20% nitrogen is 揼uaranteed?not to burn.)  Is the 10% maximum recommendation out of sync with prevailing practice and/or out of date?  Given current technology, is a higher % of nitrogen now OK?

Thanks.

B.L. Barefoot


Answer
1. The soil test indicate that your lawn is deficient in phosphorous which is why they recommend a high level.

You can compensate for this by fertilizing with either a balanced fertilizer such as 10-10-10. This particular formulation is available in large bags.

If you can not find it, then buy a "starter fertilizer" (such as 21-28-4) which would accomplish the same.

2. use the same fertilizer. It is correct that high phosphorous levels can help seedlings, especially if the soil is low in available phosphorous which yours appear to be. Just use the same fertilizer on the entire lawn.

3. if you apply fertilizer to a dry lawn (or at time of seeding it does not matter if dry or moist) and then water in immediately with atleast 1" of water (deep long soaking) there is no reason to expect lawn fertilizer will burn new seedlings.