Will Fertilizer Burn My Lawn In Summer?

For some reason, folks are highly concerned about summer lawn fertilizers and heat. I’m not sure where this stems from but I will help you out now: no, they will not burn your lawn in any greater fashion in heat than they will in cool temps.

Heat doesn’t really make fertilizer more “volatile” or make it more “potent,” so have no fear. Now, I will say, if you are using a fertilizer like CarbonX (CX DIY) that has high amounts of straight urea nitrogen, you should not apply that to a wet or damp lawn. But that is a recommendation we have ANY time of year.

This is because the prills can end up sticking to grass blades that are damp and that can burn a spot or two here and there. The urea releases nitrogen very quickly which brings fast results but we want that released down in the thatch or at the surface of the soil, not on top of the lawn. So we recommend applying CX DIY to a dry lawn, then water it in with at least ¼” of irrigation. This spot burning is very rare but I figured I’d point it out anyway.

If you have any fear of this, then just use XGN DIY (X-Green) which has a homogenous prill and won’t burn wet or dry lawns. You can review my summer fertilizer recommendations here:

  1. Summer fert strategy and store bought options
  2. Summer fert strategy with cool recommendations from our stores.

Now, if you do happen to OVER-apply fertilizer your lawn using ANY fertilizer, you could do some damage, but again, this has nothing to do with summer heat. Over-applying fert in spring will damage the lawn the same as it will in summer.

This is why I recommend measuring your lawn into sections. Then test your fert in one single small section with only enough fert for that single section. This method makes it nearly impossible to over-apply.

One of the biggest mistakes folks make with fert is they look at the spreader setting on the bag, let’s say a “setting 4” on the Scotts spreader… then they dump an entire 30lb bag in there and go off and run to do their entire lawn. Then the email I get is something like this:

“Hey, I have a 10,000 sq ft lawn and so I put in 30lbs of fert, set the spreader and took off, and by the time I was only halfway done with the lawn, the entire spreader was empty! Did I burn it?”

In most cases, even with a double overloaded app (of ANY fert) you are not going to burn anything… but you sure better go ahead and water it in good, and get ready to mow a lot! But back to my advice here:

All spreaders are different and can be off in their adjustments, bent, twisted, broken or old. Even if you may be old and walk too slow or your overlaps can be too tight together. This is why I ALWAYS recommend you practice and learn on a VERY small section of lawn with only enough in the hopper for that small section. Use that as a test, a learning, gain experience then adjust going forward before you attempt your entire lawn. I have a video where I went through this using an over-the-counter product and I will time stamp it right here for you in case you need a review:

The product in that video - don’t use that now, it’s too late in the year! But I do recommend you look at the strategy and thinking behind the video - see how I work it out and if you have the “fear of the fert” get over it! Don’t let that fear keep you from taking action, even as we head into summer!


No Fear Summer Lawn Fertilizers

Now even with all that, some of you will still have some fear that your could burn your lawn so let me give you some “fool proof” ferts here that even if you were to just go gangbusters crazy you’d be ok. (that’s not a challenge by the way!)

Milorganite - Summer Lawn Fertilizer

Our old favorite, brings great results and actually works faster in summer heat. That is because it is organic and breaks down and releases those good nutrients when it’s hot out, albeit slowly.
If you look at my lawn in last week’s video about Brown Spots In The Lawn: Fungus And Disease Options, you can see how nice and green my lawn is just 5 days after my Memorial Day Throwdown!

8-1-8 XGN DIY (X-Green) - Summer Lawn Fertilizer

I chose 8-1-8 XGN DIY Homogenous Turf and Ornamental Fertilizer as my mid-spring application this year and got great results. It brings lower N so it doesn’t push growth, has higher potash than most ferts, and also contains iron. It’s a very well rounded fertilizer and is fast becoming my favorite for all grass types. Get XGN 8-1-8 XGN DIY Homogenous Turf and Ornamental Fertilizer here, now available in smaller bags.

Will Liquids Burn My Lawn?

Lastly, people also think liquids will burn the lawn, this is also NOT true. There is some really bad info out there about water on the lawn hitting hot summer lawns. I have heard people say that watering in the afternoon can burn the lawn too. This is completely false. I live in Florida and it rains here every afternoon in summer when it’s 95 degrees outside. Sometimes very heavy, other times just a light misting. You NEVER hear about mass lawn burnings across our state do you?

Liquid bio-stimulants are great for the lawn all summer - just keep within the labeled rates. And that is the other thing here, people keep asking:
“Can I apply all 4 bio-stimulants together?”

The answer is “DON’T”

You are not going to burn anything but dang man, you don’t have to cure the problem in one miracle application. If your doctor gives you some medicine, he says “Take 1 pill per day for 30 days” he doesn’t say “take this entire bottle today and feel better tomorrow.”

Bio-Stims are a long term fix to bad soil. Apply them over time. They work to improve all your other lawn applications: fertilizers especially so be sure to apply them in and around when you fertilize and in between. Apply them when you feel the urge to throw down. Apply the MicroGreene when you want a push of green color, apply the Air8 when you want to relieve some compaction, apply Humic12 and RGS in between, but spread around that goodness.

Hope that helps you this week in your lawn strategy - we have summer just getting started now and there is plenty of time to make great progress yet this season.

I’ll see you in the lawn

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