# where to get fertilizer

I got your results from my soil test and the recommended application is 20-10-20. Where do I get this blend?

Ramsey County Minnesota

## 3 Responses

To start with, you probably should not be fertilizing your lawn now. Wait until early autumn to put down fertilizer. You risk burning or otherwise damaging your lawn by fertilizing in the hot part of the year:

http://www.extension.umn.edu/garden/landscaping/maint/calendar.htm

Unfortunately, the soil testing lab can't predict the formulations produced by the various fertilizer companies. To complicate matters further, state and local laws now forbid lawn fertilizers from including phosphorus, which promotes algae growth in our lakes. Since you have a test showing a P need, you can bypass that law, but still, the lawn fertilizers reflect the law and generally don't have a P component.

But there are workarounds, which require a little arithmetic. One of the exceptions to the no-P laws is starting a lawn. So a good source of P for lawns is in "starter" fertilizers. For example, Scotts makes a 24-25-4 product. When you combine this with a more typical lawn fertilizer (for example, Scotts makes a 32-0-4 product) in the right proportion, you will get your N and P taken care of. To get the K, muriate of potash (0-0-60) is a good choice. Of course, you can choose other blends, but you'll probably need a "starter" product to get the P and you'll probably have to use an almost-all K to get the K.

To do the arithmetic, you should use the pounds of N, P and K required for the season for your lawn (instead of the 20-10-20 ratio). These numbers are prominently displayed on your test report (and will be in the same ratio as your 20-10-20):

http://soiltest.cfans.umn.edu/sites/g/files/pua891/f/media/example_soil_test_report_home_lawn.pdf

Remember that these numbers are how much is required for an entire season, not a single application. So you will have to divide this by the number of fertilizer applications.

I'd first compute how much "starter" fertilizer you need to satisfy the P requirement. Then fill in with the standard lawn fertilizer to complete the N. Finally, complete the K with an all-K fertilizer.

Next year, get another soil test done. P and K are not depleted as fast as N, so it might be that you can use a more standard lawn fertilizer next season.

Ok Dennis, I'm still a little confused. I'm getting ready to due my second fertilization for the fall.

Here is my supplies as you advised on.

I purchased a 8 Lb, bag of " High Yield" 0-0-60 & 20# of Scotts 21-22-4 & 12.5 # of Scotts 32-0-4.

Approximately 6,500 sq /ft of lawn. And I have a Scotts Broadcast Spreader.

Please Instruct me on how to apply,'Thanks