View Full Version : High pH level
05-06-2010, 11:21 AM
Fist some vitals: Clay soil, Fescue mix, southwest Ohio. Lawn gets lots of sun.
Did a soil test and found my soil has a pH of 8. I also discovered my nitrogen levels are low. Now as far as I know the pH should be around 6 or 7. This tells me I need to apply some Aluminum Sulfate.
However, as I understand it applying Aluminum Sulfate can be tricky. Too much and it will bleach the lawn. I'm a little hesitant to go out and grab a couple bags considering it's about time for me to put down Scotts Step 2.
Will applying both of these be too much for my lawn to handle at once? Or any tips on how much Aluminum Sulfate I should apply?
05-06-2010, 12:22 PM
I would suggest ammonium sulfate as your nitrogen source 21-0-0-24S It contains 24% sulfur. Urea and other sources of N will not lower your PH nearly as much
Ammonium Sulfate is going to temporarily acidify and lower the PH in your root zone, it won't be a permanent fix, but apply that instead of Scotts each application. There are a few different forms of AS, soluble fines and granular. Use the granular form at 3-5lbs per 1000sqft and water it in.
The best solution to deal with your high PH and clay soil would be the addition of an acidic organic source. First cut your grass short, 2nd aerate two or three times then top-dress the turf with 1/4 to 1/2 inch of high quality reed-sedge peat or compost. Apply the Ammonium sulfate @ 5lbs both before and after the topdressing.
Compost contains more nutrients, but peat has more humic and fulvic acids. Peat has been decomposed for a much longer time and it will last longer in the soil than compost. Either one will work well.
Its likely that you will never get the PH to stay down, especially if your irrigation water has a High PH but this is about all you can do.
Milorganite would also be a great fertilizer to use because it has many of the essential metals in a plant available form. Use this instead of AS during the hotter summer months when irrigation is heavy.
05-07-2010, 02:37 PM
Thanks for the tips, Quack.
I'll look into AS. I'll also need to treat the lawn for weed control... is there a specific amount of time I should wait after putting down the AS?
05-08-2010, 12:22 AM
It doesn't really matter, but liquid (AS) is used in weed control to enhance the effectiveness of herbicides. More product will enter the plant if it absorbed and translocated with a nutrient.
When using a herbicide keep in mind that it is slightly damaging the turf. You probably won't see the damage but it is happening. Use the low rate and wait 3-4 weeks to reapply. Make sure the weeds are good and healthy and spray between mowings. Don't apply anything to wet turf. You might have to "blanket apply" the first time but then you should just spot spray when its mostly cleared up.
In most situations a healthy stand of grass will minimize weed presence and the need for herbicides.
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