I'm no expert, but hopefully some will chime in on your question.

FWIW, I live in Minnesota as well, and one thing that helps my yard to be more drought tolerant is to let it grow taller thru July-Aug. I'm not sayin let it grow wild, but mow on the highest setting or next one below.
Three benefits:
1) You probably won't have to mow as often,
2) and you can water less frequently,
3) and still have a decent looking lawn

Good idea ... I've been moving it all spring and summer at about 4 inches tall. Do you mow even higher than that?

I wouldn't fertilize in the summer, but it's fine to fertilize in the spring. If you do fertilize in the summer, use an organic or some other slow release fertilizer and fertilize lightly.

You are running two different but related ideas together.

Yes, most recommend against fertilizing cool season grasses in mid summer. Most suggest giving it most of its fertilizer needs in the fall. Many recommend three apps in the fall, and then one in the spring.

And, yes, you should try to get your roots to grow deeper to get to the point where you can water less. However, watering deeply and infrequently is the way you primarily encourage deep root growth. Not fertilizing in the heat of the summer is based on trying not to encourage top growth when the plant is already under heat stress. Timing of fertlizing has little to do with depth of root growth.

Adequate fertilizer and deep and infrequent watering is the way to encourage deeper roots. As it aerating when needed. As is, imho, using organics to increase the health and improve the tilth of the soil so roots can penetrate.

To add on the already good advice, most cool season grasses only require about 3 pounds per 1000 sq ft of nitrogen per year. KBG may be a little bit heavier feeder at 4 pounds and tall fescue could probably get by on 2. Its not so exact, but more based on soil type, soil structure, water capacity, weather, and what you want it to look like.

A soil test will describe the NPK ratio you should be applying. You should also be looking for a slow release fertilizer, especially in Spring.

I agree with others not to fertilize in the summer unless you are willing to do all the other cultural actions for a specimen lawn.

OK, I'm not trying to thread jack here. But, I keep seeing conflicting information on this board about encouraging deep root growth and watering in the Summer. Many are still telling others to water deep, but infrequently in the heat of Summer. However, many have said that during the heat of Summer the roots are not growing very much, if at all, and that they tend to shorten a little bit. My question is, if they're not growing hardly at all, then isn't trying to encourage them to grow deeply during the Summer the wrong approach? I would think that, given this information, you'd want to spread that ~1" out over several days during the week in the Summer.

I began this Summer watering 1" all at once, each week. My grass didn't really look the greatest with this approach. I then switched to putting that 1" down in 3 separate waterings during the week. My grass now looks almost as good as it did this past Spring, even though it's been in the upper 90s for the past week (and mid 90s before that). During the spring I was barely watering at all due to the abundant rainfall, but on the weeks where it didn't rain, I put down 1" all at once.

I'm not an expert, and I've learned quite a bit from reading these forums. However, given my own results from switching from once a week to 3 times a week during the Summer, I'd suggest re-thinking the watering approach during this time of year.

The advice to water only once a week even during the heat of the summer has been around for a long time, and some people still stand by it. I was never really able to get my lawn to do well watering once a week so I questioned whether it worked when it is really hot and dry (which basically means June through August for me). Last year, some people found some research indicating that grass roots don't grow in the summer and may end up pulling back a little, so it is better to split the inch into 2 or three sessions.

One university (I think it might be Michigan) recommends giving a light spray in the afternoon on a daily basis during the hottest part of the summer. I don't do that because it's so dry here that much would evaporate before even hitting the ground.

As far as fertilizing during the summer causing more water use, it does, in a way, but it's indirect. As rcnaylor pointed out, the main problem with it is that you're causing a lot of top growth at a time when the plant is already stressed. In order to provide the top growth, the grass uses more water, but that's sort of a side effect of the growth at the wrong time.

bpgreen said "As far as fertilizing during the summer causing more water use, it does, in a way, but it's indirect. As rcnaylor pointed out, the main problem with it is that you're causing a lot of top growth at a time when the plant is already stressed. In order to provide the top growth, the grass uses more water, but that's sort of a side effect of the growth at the wrong time."

I couldn't agree more

Skizot said "I would think that, given this information, you'd want to spread that ~1" out over several days during the week in the Summer."

I disagree and heres why.

Roots are are constantly growing, spreading, contracting, etc etc. Sure it depends on the season as to how rapidly, but its a continual process of all plants, trees, grasses, weeds etc. Now, as for watering turfgrass: Adjust the Irrigation Frequency, Not Amount of Water Applied. Turfgrass irrigation requirements vary by location, time of year, soil conditions, shade cover, type of grass, amount of fertilizer applied, rainfall, and other factors. That's why there is no one single recommended irrigation frequency; rather, you have to take all of these factors into account. Because of this variability, frequency of irrigation should be adjusted according to your lawn's needs and the amount of rainfall received. How frequently you irrigate can and should be adjusted based on these needs. The 1" once a week is a rule of thumb, not a hard fast rule.

The amount of water applied at each irrigation should remain consistent. Depending on location, there may be different amounts of soil for roots to grow into. For example, in southeast Florida, there may only be a few inches of actual soil before you hit the limestone aquifer. In other parts of the state, there may be several feet of soil for roots to grow into. Your objective should be to train the roots to grow as deeply as possible. If turf receives frequent, shallow irrigations, the roots will happily stay in the top few inches of soil, but if water is applied for longer periods, roots will seek the water out at the deeper soil levels, no matter what time of year. Deep roots can generally be achieved by applying 3/4 to 1 inche of water each time you irrigate.

I have St.Augustine Floratam and live in Clearwater, FL. Its brutally hot and sunny hear most of the year. I have sandy soil with little organic matter. In the middle of summer I can go about 5 days between irrigating.(3/4" water) If we get an 1" or more of medium rain I can go appox 7-10 days between waterings. My grass shows signs of heat stress (wilting) in the hot afternoon sun 1-2 days after I irrigate. This does not mean its time to water. The grass does this to decrease surface area and conserve water in the leaf tissue. By the next morning the grass looks fine. If I notice the grass still wilted in the morning, I run my irrigation early the following morning. (1am)

Skizot makes a good point. The next two posters answer it well.

To paraphrase, all gardening is local. As Skoot notes, the inch a week is only a rule of thumb.

One other thing that might help some is to remember that the best time to condition your yard to have deeper roots and need less watering is when its not hot. I try to encourage my grass to root in in the fall and spring. Then, like BP, I go as long as I can in the hotter weather, but that still usually means more often than once a week when it is really hot and dry.

It depends on how deep you got those roots to go before the hot weather hit as to how long you can go.

Soil and rainfall of course are other big factors we have no control over.

skoot_cat, I believe you read my response incorrectly. I didn't say anything about adjusting the amount of water applied, nor did I say that you should put exactly one inch of water down. Also, the ~ symbol means approximately, and my statement of "you'd want to spread that ~1" out over several days during the week in the Summer." means exactly what it says, and exactly what you put in bold -> adjusting the irrigation frequency. I don't think I've ever had a post misinterpreted as badly as you just did, but that's OK.

You completely distorted what I said. My point was that during the Summer months, most of us aren't getting any rain, and applying the 1" (or however much you put down, and obviously you should take into consideration the rainfall that week; I never said anything to the contrary) should not be done all at once; it should be spread out over the week. Yes, if it rains, and obviously depending on the amount that fell, you should adjust the amount of water you apply with your irrigation system. Once again, my point is that your grass will probably do a lot better during the Summer if you split your cycles up, instead of doing it all at once.

Also, you bring up St. Augustine, which is a warm-season grass, and hence a whole other ballgame. I've got TTTF, which is a cool season grass. I guess I should have mentioned that originally. However, I don't see how my original statement wouldn't apply to both types of grasses.

Please, don't twist what I've said. I thought it was pretty straight-forward.

Skizot- I dont think I twisted what you said at all or Im still not following you. let me see if Im understanding correctly. You said "I would think that, given this information, you'd want to spread that ~1" out over several days during the week in the Summer." It sounds to me like your saying (example: apply .25" of water 4x a week to equal 1" of water.)

Am I correct?

skoot_cat, I guess you didn't read my previous post. I said to take into account the time of year - I've said each time, Summer. I've also said to take into account rainfall, and I've said that the 1" is approximate, and I'd say that that amount is more based on how you want your grass to look, than anything else. For some reason, you're still not following, even though almost everything I've said is in agreement with what you've stated. So, here are some examples:

Preface: If you're happy with the way your grass looks with the amount of approx. 1" a week, then that 1" represents total rainfall that week + total manual irrigation (for some reason, I think that's the major point you keep missing). If you're happy with the way your grass looks with 0.5", then use that.

Example 1:
It doesn't rain at all during a period of 7 days. So, if 1" of water is the amount you put down this time of year to get your grass looking the way you like it, then I'm saying to apply that 1" 3 times during that week, which would be 1/3" each time. This is implied, but I'll spell it out anyways: you spread those three cycles out; obviously they aren't all in a row. What this means is that you don't put the whole 1" out during the first day of that period, and then none for 7 days, it means just what I've stated.

Example 2:
It rains 0.5" at the beginning of the week. Well, now you can obviously go a little longer before applying the next batch of water. So, you have two options, either go with two more cycles of 1/3", which would give you 1 1/6" for that week, or go with only one more cycle, which would give you 5/6" for that week. Now how many days after that rain, but within the 7 day period is up to you. So, the amount from rainfall has been factored in to this example.

Example 3:
It rains 1.0" during one day. You can now either wait a whole other 7 days before starting your 3x a week again (once again, keep in mind, this 3x frequency is what's working for me given the hot weather we've been having - the point is more than once a week). However, I'm saying I wouldn't do that. I would just consider that week the grass gets over its 1" weekly amount and I would start the 3x cycle over again in about 4-5 days. So, once again, the amount from rainfall has been factored in to this example.

I can come up with more examples, but hopefully you've gotten my point now. Most of us aren't getting anywhere near ample amounts of rainfall during the Summer. Most of us have hot Summers. And if neither of these describes your climate, then obviously this doesn't apply to you; once again implied. So, all I said was that the frequency of watering, not the amount, should be increased during these weather conditions, instead of following the rule of "approx 1 inch (or however much you put down, once again) all at once during the week to encourage deep root growth." Also what I said in my original post was that this old school saying should be followed when the temperatures have cooled, and the rain comes back - namely Fall and Spring - when the roots are growing at a much more rapid rate than they do during the blistering heat of the Summer. You'll obviously have much more luck getting them to grow deeper by training them this way during those times of the year. That last statement in bold is exactly what you've already said, so I'm really having a hard time understanding why you're not following me. But that's fine, this is an Internet forum, and I don't expect everyone to follow me, or even listen to what I have to say; it's not going to ruin my day. :-)

The reason I stated rainfall in my previous post is to give more information/detail, not to contradict you. The reason I noted rainfall was to give you/others an example of how a deep watering/soaking is beneficial and can increase the times between waterings. (which you stated and have witnessed) The same thing can be done with your irrigation system.(if its designed properly)

I completely understand what you are saying, You are not understanding what Im trying to say and this is where I disagree. Heres what I meant when I said "Adjust the Irrigation Frequency, Not Amount of Water Applied." For manual irrigation: Apply approx 1" of water each time you irrigate. Whether it be 1 or 3 times a week. Another example: Water 2x a week with approx 1" of water at each cycle, for a total of approx 2" of water for the week.

The very best plan is to let your lawn tell you when it needs water. Then apply approx 1". If you apply approx 1" of water, Your lawn should be able to go 5-7 days between waterings in the middle of summer. (Unless you live in the desert)

In your examples:
Example 1 - is a perfect example of shallow waterings. The grass roots will remain happy in the top few inches of soil no matter the time of year.

Example 3 - If your grass can go for appox 4-5 days after 1" or so of rain, it can do the same with 1" of water from your irrigation system.

No matter your location(except the desert) your lawn can and will benefit from deep/infrequent watering. Like I said before here in Hot Sunny Florida I water about every 5 days with approx 1" of water. During the winter months I water about 2x per month with 1" of water.

skoot_cat, like I've already said, this is just an Internet forum, and you're rightfully entitled to your opinion. But, without scientific research backing up your claims, it is nothing more than just that - your opinion. A lot of stuff you read on the Internet is, so obviously it should all be taken with a grain of salt. The same applies to everything I've said, it's just my opinion. However, it works fine for me, and I've got the best looking grass in my neighborhood, and my water bill isn't breaking my wallet either. So, to each his own; I was just throwing my opinion out there.

Scoot--I used to agree with your approach, it probably works well for warm season grasses, and once I get my native grasses, I'll agree again. For most cool season grasses, the roots are shorter in the summer, so if you give the lawn an inch of water each time, you're wasting water.

You want to water slightly past the root zone of the grass. This encourages the grass to grow deeper roots. However, in the summer, most cool season grasses have shorter roots, so if you water an inch, you're watering well past the root zone and the roots won't go any deeper anyway. If the roots go down 4 inches and an inch goes down 8 inches, it doesn't do any good to use an inch of water.

Once my native grasses dominate, I'll probably water only once every other week and will try to apply at least an inch. But the native grasses cope with heat by growing deeper roots. KBG and many other cool season grasses deal with heat by growing more shallow roots (seems like a contradictory approach, doesn't it?).

Hi I just wanted to chime in. I'm not going to add to any of the discussed arguments here. I'm simply here to say that.
1. I fertilize in the summer right around July. Organic Milorganite-does 0% damage to lawn in high heat.
2. I water in the summer twice a week, half hour watering sessions
3. I mow the grass on the highest to second highest setting depending on temps..The hotter the higher I mow.
4. My lawn is the least stressed and best looking in the neighborhood this year and It was just planted last September.

So I say water it, give it some organic food and mow it in the summer.

Now go have fun :)

PS. i would like to thank Bestlawn for all the support and info you provided me last fall!

In the heat of summer:
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"PS. i would like to thank Bestlawn for all the support and info you provided me last fall! "

Unfortunately, she probably won't see this. GW banned her a couple of months ago.

"Unfortunately, she probably won't see this. GW banned her a couple of months ago."

Dude! What happened, was she putting walmart and home depot out of business by sending us to private sod farms for seed?

Your soil type is a huge factor in determining watering depth and frequency.

If you just blindly put down 1" at a time once a week (assuming drought conditions), you're asking for trouble. It's really quite simple: when the lawn just starts to show stress, give it water. How much? More for sand, less for clay. Find the sweet spot.

I put down about 2" per week in 2-3 applications, but I have extremely sandy soil. We got 6" of rain in 7 hours a few weeks ago. It came in three storms, and we had about 4.5" total after the second. The standing water from that deluge was gone from the yard within an hour before the last 1.5" fell a bit later. Water that drains that quickly isn't going to be available to the grass because it's going to leave that root zone in a hurry. That requires more frequent watering.

Clay retains that moisture far better and just doesn't need as much frequency, but you have to have to watch the depth because you can end up with standing water.

What is a KBG lawn? Just curious. I live in Michigan and rely on a Michigan State Turf grass expert for my lawn care needs. He says we only need to fertilize once per year or we are wasting our money and time. The best time to fertilize is in late October or November, provided there is no snow. If it does snow, I wait until it melts and then quick run out and fertilize. So far I have been lucky. I do use crab grass killer in the spring which has a little nirogen in it to green up the lawn. If needed, so far I haven't needed it on this lawn, in July I apply grub X. I only use a winterizer fertilizer with no phosphorus in it. Michigan is very high in phosphorus so no need to add more. I do not water my lawn. By keeping my mower set to 3.5 - 4 inches I have a lush green lawn with no weeds. If some weeds to crop up, which they tend to do, I treat them in the fall with a liquid in my hose end sprayer. The best time to treat weeds is in the fall when they are actively growing. So far his advise has paid off for me in the time savings and monetary savings. Good luck.

KBG is short for Kentucky Blue Grass.

"Roots will not actively seek out water but will follow a receding water table" (anon). We take advantage of this concept by applying water as often as necessary to keep the soil in the area of the root tips wet enough to facilitate root elongation. The water holding capacity and percolation rate of the soil are the chief factors to determine how often. The percolation rate would determine how much. I keep in mind the animation of waves radiating form an antenna and apply it to water moving downward in the ground. Each pulse represents an irrigation and the wave line can be likened to the (perched) 'water table' that results. As it moves downward and gets 'weaker' we send another pulse to restore a gradient of moisture through the (12" to 18") layer of soil where we want to develop maximum root growth - a true turf.

Can I add something? For the needs of the grass, who cares water 1/3" 3 times a week or all at once one time a week. If you have the ability to water the lawn, why worry about attempting deep root growth for drought resistance...there will be no drought if you can water regularly, right?

BUT

If you keep that top 2" of soil always moist, the grass will be happy, but so will the weeds that do not have deep roots. Since my KBG has matured, I barely water. I wait for the grass to stress for a day or two, then hit it all night with about an inch of water over ten hours. The weeds have disappeared, and I can go 7-10 days or so without rain or water. Most weeds are shallow rooted and can't withstand dry soil conditions for several days.

We all have different soil types, grass types, and enviromental conditions to contend with so no two people can expect to have the same schedule work for them. There will be adjustments in watering frequency and amounts needed.

I still think it helps to keep the top layer dry to control weeds and prevent fungus and disease as well.
Oh well, whatever works best for you right?

It seems to me, that the kind of fertilizer you use should also be taken into account. I agree that applying a high nitrogen fertilzer in the heat of summer is going to encourage lots of top growth and water consumption, but what about fertilzer with a greater balance of phosphorus and potassium?

Check out the article below about how plants use the different nutrients in fertilizer.

It says phosphorus encourages root development and potassium has a whole range of benfits including root development, heat and drought tolerance, and desease resistance.

Is there any reason not to apply a low-nitrogen fertilzer during the summer? Seems like it might actually help it deal with the heat and drought?

Here is a link that might be useful: components of fertilizer article