Lawn fertilizer with a 2:1:1 ratio - Ask Extension
I'm having difficulty finding lawn fertilizer with a 2:1:1 ratio. Can you provide me the name of sources to purchase this?
Thank You
Knowledgebase
Lawn fertilizer with a 2:1:1 ratio #849870
Asked September 14, 2023, 9:52 AM EDT
I'm having difficulty finding lawn fertilizer with a 2:1:1 ratio. Can you provide me the name of sources to purchase this?
Thank You
St. Louis County Minnesota
Expert Response
Thank you for writing.
Can you send me a picture of the soil test or a link to the information that suggested this unusual fertilizer so that I can best help you.
Steve
Can you send me a picture of the soil test or a link to the information that suggested this unusual fertilizer so that I can best help you.
Steve
Steve,
The ratio comes directly from the information provided by the University, which was in classes by the University for a Certification in Landscape Maintenance and Design, which I fulfilled.
The information we were provided in class was that if fertilizer is applied three times in a season, in Minnesota, the ratio for Fall fertilizing was 2:1:1.
Has the University changed its parameters in this regard? If so, what are they currently recommending? The total seasons ratio we were given in class, if three applications was followed, it was 5:2:1. Has that changed also? If it has changed what are the current recommended ratios?
Thank you,
Dennis H
Thank you for writing back.
This course is offered by MNDOT (although the curriculum may have been developed in consultation with U MN). I am working to answer your question.
This course is offered by MNDOT (although the curriculum may have been developed in consultation with U MN). I am working to answer your question.
Hi,
I have figured out part of the answer. Fertilizers have an NPK number which gives the % of each nutrient.
For example a ten pound bag NPK of 10-2-5 would have 1 pound of nitrogen (10%), 2/10s of a pound of phosphorus (2%), and a half pound of potassium (5%).
That gets you part way to how much fertilizer to use. The second half of the calculation requires knowing how much area you are treating with that 10 pound bag. If you are treating 2000 square feet (a 40x50 lawn), you would be applying half a pound of Nitrogen, a tenth of a pound of phosphorus, and a quarter pound of potassium per thousand square feet.
Generally, you do not want to apply more than a half a pound of sustained release Nitrogen per 1000 square feet per application to minimize the risk of nitrogen burn.
The part I do not get is the phosphorus recommendation. Minnesota law https://www.revisor.mn.gov/statutes/cite/18C.60 says,
See the last couple pages of this document for Phosphorus applicaations on new, tested, untested, and established lawns.
https://www.mda.state.mn.us/sites/default/files/2018-09/RevisedTurfFertBMPs.pdf
I hope this helps, write back.
I have figured out part of the answer. Fertilizers have an NPK number which gives the % of each nutrient.
For example a ten pound bag NPK of 10-2-5 would have 1 pound of nitrogen (10%), 2/10s of a pound of phosphorus (2%), and a half pound of potassium (5%).
That gets you part way to how much fertilizer to use. The second half of the calculation requires knowing how much area you are treating with that 10 pound bag. If you are treating 2000 square feet (a 40x50 lawn), you would be applying half a pound of Nitrogen, a tenth of a pound of phosphorus, and a quarter pound of potassium per thousand square feet.
Generally, you do not want to apply more than a half a pound of sustained release Nitrogen per 1000 square feet per application to minimize the risk of nitrogen burn.
The part I do not get is the phosphorus recommendation. Minnesota law https://www.revisor.mn.gov/statutes/cite/18C.60 says,
See the last couple pages of this document for Phosphorus applicaations on new, tested, untested, and established lawns.
https://www.mda.state.mn.us/sites/default/files/2018-09/RevisedTurfFertBMPs.pdf
I hope this helps, write back.
Hi Steve,
I thoroughly understand what NPK is and the percentages, and wight per 1K sq feet. The "non-phosphorus" regulations are new to me, but I have not been asked to maintain a lawn for decades. Based on this information I will be looking for a 2-0-1 fertilizer, as MN regs do not necessarily apply to all other States.
After receiving your latest email I checked on the web and a fertilizer that is very close to my specs would be the following;
Steve, thanks again for updating this out of date old man.
Dennis,
Try though I might, I cannot learn if this is a sustained release fertilizer. Be careful as per my earlier comment to avoid nitrogen burn.
Steve
'Trust but verify'
Geezer MG
Try though I might, I cannot learn if this is a sustained release fertilizer. Be careful as per my earlier comment to avoid nitrogen burn.
Steve
'Trust but verify'
Geezer MG
Steve,
Your help is appreciated. My preference has always been slow release Nitrogen, but without a degree in Chemistry it is often difficult to understand product claims by commercial interests. At one time I preferred Milorganite, but it's no longer allowed for residential existing lawns.
Thank you for the information.
Dennis H
I bought milgornite at Gertens.
In truth, there is not much difference between brands aside from the implications of the NPKs.
Best to you
In truth, there is not much difference between brands aside from the implications of the NPKs.
Best to you
