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skizot_gw

Soil Test Results - Advice

skizot
15 years ago

OK, so I sent in two samples from my backyard to be tested. Here are the results:

Sample Area #1

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pH: 6.1

Nitrogen: 1

Phosphate: 3 (very low)

Potash: 182 (medium)

Organic Matter: 1.7%

Iron: 54

Sample Area #2

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pH: 7.5

Nitrogen: 3

Phosphate: 10 (low)

Potash: 180 (medium)

Organic Matter: 2.5%

Iron: 35

Lawn Info

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Grass Type: TTTF

Age: 13 months

Zone: 5a

I have no idea why the pH is so drastically different between the two areas in the back yard, but where it is 6.1, the grass always looks yellower (which is contrary to what one would think, since the higher the pH, the less available the iron is to the grass plant; so I would think that the grass would look yellower where the pH is 7.5).

Here are the recommendations made by the extension agent:

pH (sample #2): The pH is fine for Turf-type fescue, but if you have other plants (trees, etc,) in the lawn, you may want to lower the pH by adding 20 pounds of sulfur per 1,000 square feet. However, only 5 pounds of sulfur per 1000 square feet should be added at one time to established turf. Sulfur can be added each March and September until the total amount has been applied.

Iron (sample #2):The level of iron is adequate. There is very likely more iron present in the soil that is not available to the plants because of the high pH.

Your soil is very low in phosphorus and medium in potassium.

A 9-15-13 fertilizer at the rate of 11 pounds per 1000 square feet.

A 9-13-7 fertilizer at the rate of 11 pounds per 1000 square feet.

A 10-20-10 at the rate of 10 pounds per 1000 square feet.

A 11-15-11 fertilizer at the rate of 9 pounds per 1000 square feet.

Phosphorus and potassium tend to bind on the surface layer of the soil where roots may have difficulty absorbing them. It will help if the fertilizer is applied in September immediately after the lawn is core aerated. This will allow the nutrients to penetrate more deeply into the soil where roots are more likely to take them up.

September Application: You will need to core aerate and apply one of the above fertilizers two Septembers in a row. Every September after that use a high nitrogen fertilizer at the rate of 1 pound of nitrogen per 1000 square feet. Or you may use a high nitrogen lawn fertilizer such as a 27-3-3, 29-3-4, 30-3-3 or something similar at the rate suggested on the bag. Continue to core aerate each September to relieve compaction and increase soil aeration.

So, is this advice pretty good? It makes sense to me, but I'm not sure where I'm going to find fertilizer with those percentages. Since my yard is severely low in Phosphate, and that's the element that most fertilizers have very little of (because of ground water contamination I'm guessing), I think I'm going to have trouble finding fertilizer to fit my soils needs.

If I've done my math correctly, all of the above recommendations of fertilizer yield basically the following lbs / 1000 sq. ft.:

N: approx. 1 lb. / 1000 sq. ft.

P: approx. 1.5-2.0 lb. / 1000 sq. ft

K: approx. 1 lb / 1000 sq. ft.

I have seen a "general purpose" fertilizer that's rated at 12-12-12, but I'm not sure about applying 1.5 - 2.0 lbs of Nitrogen at once. I'm also trying to slowly convert over to organics, but there's no way I can fulfill these types of requirements with SBM, CGM, Milorganite, etc.

Thanks in advance!

P.S. - Where do I get sulfur?

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