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How To Water and Fertilize Your Lawn in Summer

by Allyn Hane 05 Jun 2019

Welcome to summer y’all!

Did you even realize that official summer starts June 21, just a couple weeks from now?

That said, in today’s email I’m going to talk about fertilizing strategies in the summertime.

It’s a question I’ve been getting a lot lately and it centers around:

“Allyn, now that it’s hot out should I still fertilize the lawn or back off a little?”

Answer: more than you ever wanted to know below, but for the most part, think of spoon feeding in heat… that is the cadence. It’s ok to push it, but not too hard!

Water Is Key In Summer

I’ll address some of the recent weather conditions around the country but in general, if you are able to keep your lawn irrigated during the summer and therefore not allow it to slip into summer dormancy, you can continue to fertilize every 4 weeks or so.

However, you may want to back it down some. As a general rule, we don’t want to push the lawn too hard when the weather has the potential of extremes.

Well irrigated Kentucky Bluegrass, even at its best, is going to struggle when outside temps are over 90 and there is no cloud cover.

3 days of above 90 and direct sun and I promise your bluegrass is going to be crying out for relief, ie: heat stressed.

You’ll see the blades thin out in the middle of the day and take on a steely-brown color.

That’s heat stress and the last thing you want to do when your lawn is stressed is hit it with nitrogen and encourage it to sprint.

Turf Type Tall Fescue doesn’t like it over 90 either, but it does typically form a deeper root system than KBG and therefore can hang on a little better… but still, over 90 and it’s a struggle.

Even down here in Florida right now, our St Augustinegrass is struggling and it loves 90-degree temps.

Problem here has been no rain support. Our big beefy stoloniferous St Augneeds a lot of water to keep those long arms hydrated, otherwise, it shrivels quickly, even though it loves the heat.

And so that is the first consideration: watering.

You need to be able to water that lawn through the roughest parts of summer. It’s going to need your help.

Not only just giving it enough water, but also being ready to “cool it down” if your area gets a long stretch of heat and sun.

Take the #TunaCanChallenge and you will be ready for the extremes! (video this weekend on setting up your irrigation plan - subscribe here)

In general, ½” of water is needed every 3 days in the hottest stretches for all grass types. I’ve also had to resort to day watering or syringing my St Aug during this most recent dry spell.

We are supposed to be in our rainy season right now - heavy downpour every afternoon around 3 PM. It’s what our St Augustine, Zoysia, and Bermuda lawns need to support their alpha tendencies.

May was very dry, and very hot and we got no help from rain, and even with my syringing the weakest spots everyday, I’ve still got some areas checking out.

At this point, I’m trying to mimic the rainy season and give the lawn, at least in the weakest spots, daily soaking to keep them green and vigorous.

I shouldn’t have to do this for long though… rain is in the forecast and hopefully our regular pattern will fall into line quickly.

If you want to know the type/kind of manual sprinkler I recommend, it’s this oneby Gilmour.

It does all the same stuff that I used to do using bricks to direct the waterstreams to oblong areas of my lawn like you see in this video here.

The Gilmour has a little track that does that for you and it works well.

It’s made of plastic which normally I prefer a zink base sprinkler that is a little beefier, but the Gilmour being lighter works better with lower water pressure than the heavier-duty impact sprinklers.

I will often set mine up to hit larger areas faster than even my in-ground irrigation system can do. If I need to cover a larger area with water, fast, I go manual every time.

It’s nice to have multiple weapons available when you need them. Pick up a Gilmour Impact here.

Summer Fertilizing Recommendations

This is why I tell you to slow things down a little with nitrogen in summer - because I know one of these extremes is going to come at some point.

So instead of blasting the lawn with ¾ lb/N/1,000 sq ft every 4 weeks in June/July/August, back it down to a smaller amount and spoon it in.

If you are using Milorganite or another bio-solid fertilizer like Sunniland All Natural, or Menards Ideal or OceanGro or Houactinite or whatever alternative you can find… back these down to 10 lbs/1,000 sq ft rates.

Depending which one you get, that will give you slow-release nitrogen at small amounts of .4 - .6 lbs/1,000 sq ft. Definitely considered “spoon feeding” and perfect for summer.

New here and want to learn more about this math? Scroll down to the bottom of this blog post and you can see how “Nitrogen Rates” work.

Here you can see me showing you the calcs for a liquid product.

(don’t let the math scare you! Instead, learn it so you can take more control over your lawn strategy. It’s not as difficult as I make it out to be, trust me!)

Which, BTW, liquids work great in summer too. In fact, better in some cases. Keep in mind, we need our nitrogen and other fert to get into the soil.

The smallest particle you can get is a liquid and it takes a whole lot less water to get a liquid fert into the soil. If you are regularly irrigating, switching to liquids is a great idea.

If you are not irrigating, then dry products can sit on the ground and wait, no problem there. Either will work so utilize what you are most comfortable with.

“Allyn, are liquids better than granular?”
Answer: They both have advantages but always remember, the best fertilizer is the one that you can apply the most consistently.

If you can make a better app with liquid, go that way! Same with granular - go with your strengths on this one.

The results will be there either way.

“Allyn, what about CarbonX?”
Answer: CarbonX has slow release nitrogen too! It’s bio-char with chicken poo infused in it and that right there is a VERY natural way to release nutrients including nitrogen and iron, into the soil.

You are not going to burn your lawn in summer with CarbonX -- so there is no worry there, but it works so well (it has some added nitrogen for quicker greenup), that it will cause the lawn to grow if you blast it too hard… so again, back it down to 2 lbs/1,000 sq ft if you can.

Not because it’s gonna burn, but instead, because we don’t want to push growth in heat.

If you have CarbonX and want to apply it at a lower rate of 2 lbs/1,000 sq ft then setting 6 or 6.5 on a Scotts Edgeguard Deluxe spreader will do it but that is going to be tough.

Good news is, you will NOT hurt your lawn if you go heavy.

For some reason, people think fert is going to burn their lawn and that is just not the case.

In this video here I applied CarbonX to my Zoysia at 6 lbs/1,000 sq ft which is DOUBLE what I recommend and as you can see in this video here, the grass is super dark green.

I applied that in early May when we were getting regular rains and the Zoysia sucked it right up and remains very green even now, one month later:


Summer Slow Play with Double Dark

If you want to employ a strategy that acts more as an “extension” of your spring lawn instead of pushing it further, then the “Double Dark” cocktail is perfect for summer. (full cocktail menu here free)

If you have used Ironite in summers past and want a liquid alternative that will deliver a bigger, faster punch, and still not push extra growth, the double dark is what you want.

9 oz/1,000 sq ft MicroGreene 0-0-2
6 oz/1,000 sq ft Greene Effect 7-0-0

The combination of these two is very powerful and gives a quick green that lasts longer than you would expect.

You can extend that green by applying this every 6-7 weeks.
That’s all it takes and you will not be mowing every 3 days either.

Slowing down the nitrogen will decrease your mowing frequency but heat in summer does the same thing - at least for cool season lawns.

Bermuda, Zoysia, St Augustine and even Centipede, your turf grows super fast in the summer as rains hit it - using the double dark will NOT push it to grow more but will keep it green like you like it!

Weather Extremes

We’ve had an extended heat and dry spell in the deep south.

There have been major floods across the mid-south and up into the midwest.

There have been days and days on end of rain in the north and northeast - more than normal for spring.

All of these things will zap the lawn and zap the soil and one thing they all have in common is that nutrients are lost during these times and must be replenished.

No matter what extreme you are dealing with - they all have a negative effect on the turf and we can help it recover with the proper inputs - but not all at once.

When you come off the football field at the end of a game, the first thing you go for is a Gatorade to replenish electrolytes and minerals and most of all, water.

You don’t immediately order a medium rare steak and bacon-blue-cheese-wedge… you get that a few hours later, AFTER you have replenished the basics.

Same works for the lawn - rebuild the soil with basic N-P-K and micros - slowly.

John Perry talks about this in this recent video here and explains it much better than I can.


Go ahead and fert away - but back it down, get your irrigation in line and spoon your way through summer.

You may also enjoy my most recent video where I cut out, sprayed out, and smoked out mosquitoes and other insects in my landscape.

Because at the end of the day, we have to be able to enjoy these lawns we work so hard for!

Enjoy your summer! I’ll see you in the lawn!

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