Great ph info chart.

[Skipster]

Originally Posted by rob7233

The reason that a lawn irrigated with rainwater looks better after verses tap or groundwater is that Nitrogen is very mobile and changes form readily from a gaseous state to being very water soluble being carried by rainwater. A good rain always contains Nitrogen(N) which is taken up by the lawn's root zone. I'm not sure how much but that's likely one reason any given lawn looks better after a good rain. Additionally, I also recall vaugely something about ion exchange with rainwater but can't remember anything else regarding that.

Also that with soil testing, N is not measured since it's so mobile.

I might disagree that N delivery via rainwater is meaningful. In fact, the studies I did years back showed N from rainwater was almost nonexistent. Rainwater may dissolve soem gaseous N2 from the atmosphere, but N2 isn't plant available. Some plant available N can be made in a reaction with lightning, but this usually adds 0.02 #N/M, so it doesn't add much.

Rainwater usually perks up lawns because most irrigated lawns use treated municipal water, which usually has a pH in the mid 8s, which haxs a liming effect each time the lawn is irrigated. Lower pH rainwater helps to bring pH in range for N forms to be more easily available.

Like you, I find soil testing for N to be unnecessary and to have little value. But, I was raked over the coals on this board for suggesting that. I wonder if anyone will rake you over the coals for doing the same?

[greendoctor]

N levels in soil are something I actually ignore, unless they are sky high because of someone pounding an area with fertilizer due to lack of response. True story: I have had soil test results come back advising no more fertilization. Soil pH was the issue causing the poor growth.

[bug-guy]

http://edis.ifas.ufl.edu/ss317

"Nitrogen

Nitrogen is used in larger quantities than any of the other applied nutrients and needs to be applied on a regular basis to most turfgrasses grown in Florida lawns. The Florida Extension Soil Testing Laboratory does not analyze for soil N. Nitrogen is mobile in Florida’s sandy soils and correlations can not be established between analytical soil N and turfgrass response; therefore, N recommendations are based on the turfgrass N requirement. The actual quantity of N required depends on a number of factors: type of turfgrass being grown; turfgrass quality desired; type of soil and quantity of water the turfgrass receives, either through irrigation or natural rainfall; region of the state where turgrass is being grown; amount of shade under which the turfgrass is grown -- shaded turfgrass requires less N than does turfgrass grown in full sun; and disposition of clippings during mowing practices, (if clippings are discarded more N will be needed to sustain the same quality as if clippings were returned). Detailed N fertilizer recommendations for turfgrasses are available in Soil and Water Science Department Fact Sheet General Recommendations for Fertilization of Turfgrasses on Florida Soils, http://edis.ifas.ufl.edu/LH014."

[Ric]

Originally Posted by greendoctor

I would kill to have soil with a pH range of 5-6.5. Based on the colored chart you put up, most of the essential elements are available. Problem is when pH in the irrigation water is above 7 and the soil pH is also above 7. Most warm season grasses with the exception of centipede grass and bahia grass are not that picky about being above 6.5. It does get hairy if you are expecting ornamentals to do well.

I hate to see applications done right before a 1" per hour rainstorm. No call for it in my area. Those only happen but a few times a year. There are many days where it is not going to rain like that at no more than 20" per year annual rainfall.

Florida's Gulf Coast is mostly Calcareous Sand with a average pH of 9.5. I dealt with alkaline sand for so long I don't know any thing else. I use only acid forming fertilizers and still fight for color by adding tons of minors elements.

A quick story. A new customer had the Big box Fert & Squirt company. His lawn was still yellow after their expert had soil samples etc. I don't how the fool missed the 10.5 pH on the soil report. I went to Walmart just a few Blocks away and found a straight Ammonium Sulfate Fertilizer with no minors. About a week later all the fertilizer the Big Box people put out, kicked in and I got the credit for their fertilizer.

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[greendoctor]

Didn't you get the memo: Slow release urea is supposed to be the do all, be all and end all for lawn fertilization. Using AS is antique. Why would you have to find AS in a Wallyword? Is it because the treehugging granola eaters banned it for professional use because it is not slow release urea? On a lawn with anything over 7.0, I am also throwing in 5 lb of DF sulfur in addition to the AS and micronutrients. Do not try this on lawns that cannot be irrigated after application.

[Ric]

Originally Posted by greendoctor

Didn't you get the memo: Slow release urea is supposed to be the do all, be all and end all for lawn fertilization. Using AS is antique. Why would you have to find AS in a Wallyword? Is it because the treehugging granola eaters banned it for professional use because it is not slow release urea? On a lawn with anything over 7.0, I am also throwing in 5 lb of DF sulfur in addition to the AS and micronutrients. Do not try this on lawns that cannot be irrigated after application.

I was Lazy and Wally World was only one mile up the street. I had looked at fertilizer a few days before and saw a 16-4-8 100% AS and K2SO4. I think it had a 3% Fe also. I was surprise they would carry a Lawn Burner Like that. Of course I have posted about Sulfur application many times. 10 Lb of 0-0-0-90 per thousand lowers pH one point in 30 days. 30 days mean it takes 30 days to release the sulfur.


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[greendoctor]

AS and K2SO4? Two things I seldom see in a fertilizer blended for Hawaii. Even though those two sources would be totally correct. Most landscape plants and turfgrass species are not halophytes. If someone applied that AS and K2SO4 blend evenly at no more than 2 lb per 1000 sq ft every 4 weeks, that is a good program. Much better than KCl and your coated urea du jour. I have to think about Cl. Clay holds on to Cl and there is significant salt in irrigation water.

[Ric]

Originally Posted by greendoctor

AS and K2SO4? Two things I seldom see in a fertilizer blended for Hawaii. Even though those two sources would be totally correct. Most landscape plants and turfgrass species are not halophytes. If someone applied that AS and K2SO4 blend evenly at no more than 2 lb per 1000 sq ft every 4 weeks, that is a good program. Much better than KCl and your coated urea du jour. I have to think about Cl. Clay holds on to Cl and there is significant salt in irrigation water.

At Twice the money of straight urea & KCL, AS and K2SO4 had better have a Great response. Yes this is a spoon feed blend that also means more labor. Add in a few minors and Some insecticide and you have my tank mix. Ratios of N to K etc change per season.

The point is in this case I wanted a faster response than Sulfur would give me. Sulfur lasts longer because it dissolved slowly. BTW because of our high pH, many homeowner will use a water can once a week filled 50/50 vinegar and water on their plants.

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[lawngrazers]

Is there a soil Ph test kit that is somewhat reliable. I believe that would be the first thing to check before applying any product.