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Dare I say it. Can we get a little rain?

October 18, 2010

We are just past the halfway point in October and some parts of the state have yet to receive any considerable rainfall this month. After being bombarded with rain during the summer months, the Des Moines area has received a measly 0.03 inches of rainfall so far in October. Their last considerable rainfall event took place on September 25. Depending on what happens the remaining 14 days of the month, October could go down as one of the driest on record. Irrigation systems that didn’t get much use during the rainy summer months are surely being used during this stretch of dry weather. The picture below from the National Weather Service shows that a good chunk of the Midwest is experiencing below average rainfall for October.

There hasn’t been too much activity (as far as stresses go) at the research station. We still have dollar spot working in some areas and rust and powdery mildew are showing up on Kentucky bluegrass. Grub damage at the station seems to be less this year compared to years past.

Other than the droughty conditions, the fall months have been conducive for turfgrass growth and recovery. Soil temperatures are holding steady in the high 50’s low 60’s. Those putting down natural organic fertilizers yet this fall, remember that those products require microbial activity to release the nitrogen contained in the product. Microbial activity usually ceases at 50 degrees. The dry conditions could also affect post-emergent herbicide applications as uptake and translocation are not as effective on drought stressed weeds.

I’ll leave you with some pictures of fall.

Regardless of the weather conditions, poa always seems to find a way to thrive.

This maple provides brilliant fall color on the north side of the ISU campus


Drought Damaged Lawns Need Help

September 25, 2012

While the drought of 2012 may be remembered more for its economic loss to corn and soybean farmers it also took a toll on many lawns across Iowa.  The crispy brown lawns of August have begun to recover with September rains, but all is not well.  Kentucky bluegrass is the most dominant grass in Iowa lawns.  In most summers when water is lacking the turfgrass leaves turn brown but the below ground crowns, buds, and rhizomes survive in a dormant condition only to produce new growth when water returns.  

 We have become very accustomed to letting the lawn turn brown in the summer and then watching it re-green in the fall.  The problem with this strategy is that summer dormancy is not an absolute guarantee that the grass plants will survive.   Most of the time non-irrigated lawns turn dormant in late July after about 2 to 3 weeks with no water.  They can remain brown and dormant, but alive, for approximately 4 to 6 weeks without water.  Again, these are general statements and estimates, not absolute values.  It is important to remember that the dormancy factor in Kentucky bluegrass also has its limit, and it was reached in many lawns across Iowa in 2012.  I have been driving through many new and older neighborhoods in Iowa to get a feel for the amount of turf damage caused by the drought.   

Older neighborhoods where trees shade the ground don’t seem to have as much turf loss.  Lawns with hills and slopes, especially those facing the south lost substantial turf.  Thatchy and sandy soil lawns left un-irrigated also experienced severe turf loss.  The green grass of watered lawns is easily discernible from the dormant lawns that are now struggling to recover.  My travels across Iowa indicate that most neighborhoods have approximately 25 to 50 percent of the lawns showing some degree of turf loss from the drought and of the injured lawns approximately 25 to 50 percent of the turf in each lawn has been killed.  The bad news is that some of you are now dealing with dead grass and no amount of watering or rain will make it recover.  In fact, the dead areas of the lawn that are not repaired this fall will likely be invaded by weeds next year.   

The good news is that September is the perfect month to renovate the lawn or at least reseed the damaged areas.   Don’t delay, if it is dead now it probably won’t recover and by the end of September and you will have missed the best seeding window to re-establish the lawn.  By the middle of August I determined that over 50% of my full sun Kentucky bluegrass backyard was dead.  So I set the mower as low as it would go and scalped off all the dead grass and what little green grass remained.  Next, two passes in opposite directions were made with a slicer seeder from the local rental store to plant seed in perfect little rows approximately one inch apart.  The shredding action of a verticutter or the hole punching action of an aerifier are other machines that could be used to facilitate inter seeding into the existing dead lawn.  Just make sure that you are getting the seed planted into the top ¼ to ½ inch of the soil.   Then lightly rake the surface to further plant any exposed seed into the surface.  Seed left on the surface usually remains too dry and seldom establishes.  Add fertilizer and water and watch it grow.  Water just enough to keep the top inch moist during the first two weeks; start by watering an area for ten minutes once or twice a day and adjust as needed.  There is no need to soak the soil deep because the seed is near the surface.    After the seedlings produce 2 or 3 leaves and are over an inch tall, reduce the frequency of watering to every other day and eventually to once a week. 

I seeded turf-type tall fescue on August 15th  and 28 days later my first mowing occurred on 12 September at 2.5 inches high.  I changed my front yard from Kentucky bluegrass to the more drought tolerant turf-type tall fescue three years ago and liked it so much that I was planning on killing my backyard with glyphosate and inter seeding tall fescue this year.  The 2012 drought did such a nice job of killing the old lawn that I didn’t even bother using herbicide.   If your lawn has a variety of weeds and other undesirable grasses use glyphosate to kill the undesirables and then seed into the dying vegetation.  Tall fescue is a bunch grass that could require some overseeding if it were to thin, however it has fewer disease and insect problems and because of a deeper root system will remain green about two weeks longer than Kentucky bluegrass when water is limiting and this ultimately means less irrigation is needed compared to a Kentucky bluegrass lawn.  

If you are not a fan of turf-type tall fescue then just reseed with Kentucky bluegrass or a mixture of 80% Kentucky bluegrass and 20% perennial ryegrass by weight.  Seed tall fescue at 10 lbs/1000 sqft and Kentucky bluegrass or the bluegrass/ryegrass mixture at 3 lbs/1000 sqft; both seed scenarios will cost approximately $12/1000 sqft or approximately $100 for an average lawn of 8000 sqft.  My cost for seed, fertilizer, and equipment rental to do 8,000 sqft of my lawn was $196 and my labor was free but I didn’t move real fast the next day.  A local lawn care company quoted me $280 for the same work and next time I just might watch them do it from my lawn chair on the porch.  Both could have been avoided with one ($86) or two ($172) timely irrigations to apply 1 inch of water per month during the drought to insure that my dormant turf did not die.  The take home message for 2012 lawns is that summer turf dormancy is no guarantee that the lawn will survive and that a little water is a good summer investment to avoid the expense and aggravation of having to re-establish a dead lawn. 


Prepare for a drought

Management practices in the fall and spring determine the drought tolerance of the lawn in summer. To reduce the need for irrigation, your lawn management program should maximize root volume and depth in preparation for summer drought. By the time summer rolls around, there is little you can do to help a lawn except mow and irrigate properly. The following lawn care tips will help reduce the need for irrigation and increase the chance of surviving summer drought.

  • Mow grass as tall and as frequently as possible with a properly sharpened blade to produce a dense cover with a deep root system.  Taller grass has deeper roots that draw moisture from a larger volume of soil and results in less need for irrigation. Taller grass shades the ground and reduces heat stress from high soil temperature. Two and a half inches is often recommended as a height for Kentucky bluegrass, but I am seeing a sensible trend on commercial sites and expensive neighborhoods where lawns are being mowed at heights of 3.5 and 4 inches.
  • Water deep and infrequently.  Avoid the temptation to irrigate in the spring just to get the grass growing; allow it to green up naturally.  As summer progresses don’t water until the lawn is showing obvious signs of wilt, then water deeply and infrequently; one inch of water once a week.   Irrigated lawns that do not experience brief periods of wilt are being over watered and produce shorter root systems that are not able to withstand drought and city enforced water restrictions.


Conserve water by knowing when to water

  • The best time to water a lawn is from 6 to 8 a.m. when disruption of the water pattern from wind is low and water lost to the atmosphere by evaporation is negligible.  Watering early in the morning also has the advantage of reducing the chance of turf diseases that require extended periods of leaf moisture.  Avoid irrigation during midday and windy conditions.
  • Move sprinklers frequently enough to avoid puddles and runoff.  Difficult-to-wet areas such as slopes, thatched turf, and hard soils may benefit from application of a wetting agent to improve surface penetration of water.
  • Water only when the plant tells you to.  Become familiar with areas of the lawn that wilt first (blue/purple leaves, rolled leaves, foot printing).  Water within 3 days of observing these symptoms.
  • Water problem areas by hand to postpone the need for irrigation of the entire lawn.  Some areas of a lawn usually wilt before others.  These areas, or “hot spots”, may be caused by hard soils that take up water slowly, slopes, southern exposures, and warmer areas next to drives and walks.  Lawns that have unusual shapes also may require some hand watering to avoid unnecessary watering of paved surfaces, mulched beds and buildings.  Soaker hoses that have a narrow pattern and supply water at a slow rate may be useful in these areas.
  • As an alternative, allow the lawn to go dormant by not watering.  Apply and inch of water per month to dormant cool season grass lawns during prolonged drought to avoid substantial turf loss.

Fig 1. An irrigated lawn on the left in stark contrast to a non-irrigated lawn on the right that is nearing complete dormancy.

Fig 2. A good example of deep and infrequent irrigation and beneficial wilting.  Irrigated lawn that is properly allowed to wilt before next watering.  Notice the down spout area that remains green (top left).  Front yard showing foot printing and beneficial wilting (top right).  Same lawn a week after irrigation showing rapid recovery and no injury from wilting (bottom left).


Fig 3. Lawn mown 4 inches tall (top right) and allowed to wilt between automatic irrigation cycles (top and bottom left).

Fig 4.  Lawn without irrigation allowed to go dormant. Picture taken 7-19-12 (left). Same lawn showing 25 to 50% of the lawn dead on 9-1-12 after rain and recovery (right).

Fig 5. Picture taken 8-7-12 from dormant Kentucky bluegrass lawn showing plant on left with a live bud and some green tissue and plant on right with crown and basal buds completely dead.  Dormancy is a plant mechanism that explains how a plant can turn brown from lack of water and potentially recover from basal buds, crowns, and rhizomes when water returns.  However, dormant plants under continued drought can eventually die.

Fig 6. Pictures of September lawns that did not recover from dormancy after rainfall or lawn watering occurred. 



November 26, 2013

I have been experimenting with tall fescue in various situations.  In the fall of 2012, following the serious drought that we had that year, I planted tall fescue in various parts of my lawn where I had lost Kentucky bluegrass during the drought.  This included areas on my septic mound where the soil was thin and on an area above my buried propane tank.

I had mixed results with that experiment.  We had another drought in 2013 that lasted from late June to October.  I went a full 90 days without mowing non-irrigated areas.  While some of the tall fescue did survive on the septic mound, some of it did not.  On the thin soil over the propane tank, I lost the tall fescue late in the 2013 season.  In a few other drought affected areas in my lawn, the tall fescue did survive the drought.

Tall fescue clearly stays green longer in droughts than does either Kentucky bluegrass or perennial ryegrass.  The picture below was taken at the research station in August of 2013 during the peak of this year’s drought.  The foreground is dormant Kentucky bluegrass.  The tall fescue is in the background and it remained green through much of the drought.

In this picture, there is tall fescue surrounding our perennial ryegrass cultivar study.  All of the ryegrass is nearly dormant, whereas the tall fescue around the outer edge of the trial remained green weeks longer.  

 I have also been noticing something else interesting about tall fescue late this fall.  While seedling tall fescue has remained green well into the fall, mature tall fescue has gone off color earlier that either the Kentucky bluegrass or the perennial ryegrass at the research station.  I have also noticed this on other mature tall fescue areas around Ames.  HaS anyone else noticed the tall fescue going off-color earlier than usual this year?

The light brown area on the right is tall fescue and the green areas surrounding the tall fescue are Kentucky bluegrass.



October 17, 2013

The recovery of Kentucky bluegrass following this summers drought has been amazing.  Most areas that were completely dormant in September have now recovered.  The reason for this is the rhizome system of this amazing lawn species.  The picture below shows this underground stem system and how it grows from the plant.  The rhizome is a stem and not a root.  It has buds on every node and every bud is a reproductive structure.   These buds are protected underground and can remain inactive for months.  When they are needed for the survival of the plant, the will begin to grow and form new crowns.

 Here is one of my pictures of the rhizome system on Kentucky bluegrass.  It has been estimated that one Kentucky bluegrass plant can produce as many as 1300 daughter plants in a single season, mostly from the rhizome system.

 Here are some interesting pictures that I took at the research station late in the summer and through the fall showing the ability of Kentucky bluegrass to recover.  The first picture shows an area around an irrigation repair where plywood was left on the Kentucky bluegrass turf long enough to kill all of the plants above ground.  It looks dead.

Here is a picture taken a couple of weeks later.  Notice how some green is beginning to appear.  That is regrowth from the underground stem system.

Approximately 4 weeks after the plywood was removed, the area is showing considerable improvement without any reseeding.

 This picture was taken in October.  It shows almost complete recovery.  This is the same type of recovery that we are seeing from drought affected areas this fall.  It is one of the main reasons that we use Kentucky bluegrass the way that we do in turf industry.




November 13, 2012

Quackgrass (Elymus repens) is known for its long clasping auricles and its extensive rhizome system.  It is one of the most persistent and difficult to control weeds in cool-season lawns.  Rhizomes give this species an ecological advantage over other grasses during extended dry periods.  While Kentucky bluegrass also has a rhizome system, quackgrass has a more extensive system and will out compete Kentucky bluegrass in dry years.

This was the case in this year's drought in the Midwest.  Lawns went through an extended period of dormancy that in many areas lasted for months.  This fall, we are seeing Kentucky bluegrass lawns recover. But wherever there was quackgrass in the lawn, it has gained an even bigger foothold.

Last week, I was asked to look at a lawn that one of my students cares for through his lawn care service.  It had been a mostly Kentucky bluegrass lawn up to this year, but following the drought, nearly everything that is recovering is quackgrass from the rhizome system.

Roundup will kill it, but the problem is that Roundup generally does not translocate through the entire rhizome system.  When you reseed, there is always some living rhizome tissue and quackgrass returns.  I generally recommend repeated applications of Roundup, followed by sodding.  Even that extreme treatment generally fails, however, and the quackgrass returns.

Figure 1.  Long clasping auricles of quackgrass.

 Figure 2.   Quackgrass rhizomes.

Figure 3.  Lawn in central Iowa that is nearly all quackgrass following the drought of 2012.



November 10, 2012

Here is another post from Larry Ginger of "American Lawn Care" in Des Moines.  Larry has been keeping us updated on late grub damage and fall seeding on lawns that he manages.  Below are some pictures from Pleasant Hill, Ia showing active grubs on November 9.  I am going to have to change my teaching notes on this.  Generally the grubs have burrowed deep underground by this time, but here they are in November.

Larry also reports an 800% increase in his fall seeding business.  He is using a three-way blend of Falcon IV, Five Point and Six Point turf-type tall fescues.  He will send us some pictures of newly seeded lawns next week.

I have also been seeding areas that had been established to Kentucky bluegrass in the past, but were lost to the drought this summer.  I have tried turf-type tall fescues as well in some areas and will report the success with this next season.  My main concern is how well they will blend with the Kentucky bluegrass remaining on the area.

Figure 1.  Active grub on November 9 in central Iowa.
Grub Damage

Figure 2.  Grub damage.



September 27, 2012

Here is a post from Larry Ginger of ‘American Lawn Care’.  It goes along with that post by Dr. Minner two days ago about using turf-type tall fescues for lawns damaged by the drought.

Larry seeded turf-type fescues in the fall of 2011 and was very pleased with their performance in the drought of 2012.

I also seeded some turf-type fescues in some areas of my own lawn where the soil was thin and I was having a hard time keeping Kentucky bluegrass.  I was pleased with the results during the 2012 drought and have seeded some additional areas over my septic system and over the buried propane tank where I lost bluegrass this year.  I'll let you know next year how that worked out.

From Larry:

After tiring of brown/dormant bluegrass turf over the past few years, I decided to try "turf-type tall fescue" in the fall of 2011. 

On the day before Thanksgiving 2011" I did the following things:

1) Mowed my Kentucky bluegrass lawn nearly "down to the soil surface".
2) Raked off all grass clippings.
3) Spread a 3-way blend of Falcon ll, Falcon III, Falcon IV turf-type tall fescue grass seed over top. 
4) Then I aerated multiple times.   (approx 12 passes with 3 machines running)  see Figure 1 -- lots of plugs, holes, mud.
Then we just left it alone.  Never dragged it.  Never watered.  Never fertilized.

Four weeks later on Dec. 22, the grass began to emerge.  The new turf-type tall fescue resembled "moss".  (see Figure 1)  I realize the mild weather helped.  My concern at that point was possible "winter kill", but that never happened. 

(This is surprising, I often get winter kill on late seedings of tall fescue.  I would recommend seeding in August or early September if you can.  It is amazing that this worked so well.  Nick Christians)

By April 20, 2012, I had mowed this lawn several times, and it never received any treatments of any kind.  (Figure 2).  This picture shows that my lawn was already completely established (filled in), and it had been mowed 3 times..  It's the only pic I have of my lawn from this past spring.
I was holding a one-quart rechargeable spot sprayer that I just purchased.   (A lawn care company in Kansas wanted a pic of this sprayer)

Figure 3 shows my lawn "after the drought of 2012".  It was taken August 18, 2012.  It shows a few 'semi dormant'  patches (in full sun areas), yet no areas of this new lawn are dead. During the 2012 growing season, this lawn handled the drought remarkably well.  I fertilized the lawn in late July and early August.  The first application contained Merit, the fertilizer was 50% slow release.  The second application was 3 weeks later with a 50 % slow release.   I have been very pleased with the performance of my turf-type tall fescue this year.

Larry Ginger
American Lawn Care
5880 NW 2nd St
Des Moines, IA  50313
(800) 700-6330



 Figure 1.  Just after emergence of seedlings in the fall of 2011.

Figure 2.  April 20, 2012.

 Tall Fescue Turf

Figure 3.  August 18, 2012 after a couple of months of drought with a little rain in early August.

Tall Fescue Turf



August 9, 2012

On Friday July 20, 2012, I put up a blog post about some 1988 work that we did with an Iowa lawn care company, All American Turf Beauty, that involved putting lawn care treatments on dormant lawns.  After that post went up, I discussed the possibility of updating the work in the drought of 2012.  The same questions that arose in 1988 from customers worried about damage to their lawns by late-summer applications on dormant lawns are coming up again this year.

All American has changed their program since 1988 and now use granular fertilizer in their July/August treatments at a rate of 0.5 lb. nitrogen (N)/1000 ft2.   The fertilizer is an 18-0-4 with 50% slow release N.

We applied the treatments separately to non-irrigated Kentucky bluegrass, tall fescue, and perennial ryegrass areas.  We left an untreated control, and then applied 1 plot at 0.5 lbs N/1000 ft2 to one plot, 1.0 lb N/1000 ft2, and 2.0 lb N/1000 ft2.  We also applied 1.0 lb N/1000 ft2and 2.0 lb N/1000 ft2 to separate plots using urea 46-0-0.

There are two questions.  Number 1, will any of the treatments do any harm?  Number 2 which treatments will prove to be beneficial?

The treatments were applied on August 8.  At the research area, we have had 3.4 inches of rain in the last 12 days.  The bluegrass and perennial ryegrass areas are just beginning to show recovery and the tall fescue has nearly recovered.  We had 0.3 inches of rain on the site shortly after treatment.

I will be following these plots over the next few weeks and I will be reporting on the effects of the treatments as the turf further recovers into the fall.

Thanks to All American Turf Beauty for their help with this project.

The next two pictures are of the bluegrass area by the turf building.  It was completely dormant and is just beginning to recover.

The perennial ryegrass is in the foreground and the tall fescue area in the background.  The tall fescue is recovering much faster than the rye.



August 1, 2012

As you might expect, I have had a lot of questions on watering lawns recently. My standard answer is that watering is good and you should do it if you have no shortage of water and money.  That covers about 5% of the population.  The other 95% who don’t want to spend a fortune of water or are under water restrictions are generally looking for another answer.

If you have 1 to 2 year old sod or a new seeding from last fall or this spring, I would water.  This grass may not be mature enough to survive and watering will be worth the expense.  Mature Kentucky bluegrass lawns should be fine, however.

Let me begin by sharing my experiences in the last big drought in 1988.  In central Iowa, that drought was worse than this one.  Lawns went dormant in May and did not recover until well into September.  If you remember, we had pretty good spring moisture this year.  I mowed non-irrigated turf until nearly the end of June.  In 1988, I was amazed by how well the turf recovered in the fall, even on areas that had been dormant for 15 weeks or more and had been subjected to several 100 degree + days.  

Kentucky bluegrass has an underground stem system called rhizomes.  These rhizomes are protected underground.  They have a series of swollen areas on the stem called nodes.  Each node contains a bud.  These buds have an incredible ability to survive drought and to regrow when moisture is available.   Most of the plant can die, but if the bud is alive the plant will come back.

In 1988, I looked at Kentucky bluegrass fairways on golf courses.  Where these fairways were not watered, cart traffic had worn them down to the soil surface.  I was asked if I thought that these would recover.  My answer in August of 1988 was ‘no’ I do not think they will make it and you will have to reseed.  I was wrong.  I went back and looked at these fairways in the fall and could hardly believe at how well they had recovered.  

I am betting this year that we will be fine and that most people will be surprised by the recovery when temperatures cool and the rains return.  I have not been watering my own lawn and am counting on complete recovery.

Some lawns will be damaged.  There can be grubs or other insects that damage turf.  Some will lose perennial ryegrass and may be thin following recovery.  But Kentucky bluegrass lawns should be fine.

Another common question is “should I fertilize my lawn at the regular time”.  The answer is yes, go ahead.  Even if the grass is dormant, the fertilizer will not hurt it and it will help with recovery later (see the July 20 blog).  I will be fertilizing my dry turf areas in the middle of August.

I will continue to monitor lawns though the fall and put up some updates on the blog.  This morning, August 1, I drove around central Iowa and took some pictures of lawns.  We have had an inch and half or more moisture in the last week.  I am already seeing some recovery from that moisture.  Here are some pictures from this morning.

This lawn has been dormant by for about 6 weeks.

Here is one that has received some water, but is still under stress.

Not watered on the left, some irrigation during July on the right.

Not watered on left, fully irrigated during July on the right.