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Lawn Fertilization

January 10, 2014

Today, temperatures finally began to climb out of the negatives. With the onset of warmer weather, (using this term gently) I felt it was a good time to start looking towards spring. Over the last few months there have been several inquiries regarding lawn fertilization. In response, I have revised the Iowa State University home lawn fertilization publication. Although you will not be pulling out the fertilizer bag for another 4-5 months, I thought I would inspire you with some information that will get you ready for warmer weather. The publication outlines the importance of fertilization, rates and timing of application, label requirements in Iowa, and fertilizer products in the market.


The following is a small excerpt from the introduction.

Lawns are an important component of many home landscapes. Good cultural practices are necessary to achieve a healthy, attractive lawn. One important cultural practice is fertilization. The benefits of a well-maintained lawn fertilization program are good turf color, quality and density. There are 14 elements which are often referred to as mineral nutrient elements and are generally obtaining in the soil via root extraction. The quantity of most of these nutrients contained in the soil is high compared with the requirements of turfgrass plants. However the demands for nitrogen, phosphorus, and potassium oftenexceed the supply in the soil. Thus, it becomes necessary to add these elements through fertilization.

Turfgrasses require nitrogen (N) in the largest amount of any of the essential nutrients. For this reason, nitrogen is usually applied in the largest amounts. Nitrogen nutrition is important to turfgrasses because it canaffect shoot growth and density, root growth, and susceptibility to damage from disease, heat, cold, and drought.

Turfgrasses require potassium (K) in relatively large amounts, second only to nitrogen. Potassium influences turfgrass rooting, disease susceptibility and drought, heat, and cold hardiness. The terms soluble potash, soluble potassium and K20 may be used to refer to potassium fertilization. 

Phosphorus (P) is required by turfgrass plants in smaller amounts than nitrogen and potassium. Phosphorus is important in the establishment, rooting, maturation,and reproduction of turfgrasses. The terms available phosphate, available phosphorus, available phosphoric acid, and P2O5may be used to refer to phosphorus fertilization. 

The entire extension publication is attached in pdf form.  To download the publication, click on the following link Fertilizer Publication.  


Establishing a Lawn from Seed

January 17, 2014

The establishment of a home lawn from seed can be challenging. The keys to successfully establishing a lawn from seed are selecting high quality seed, seeding at the optimum time, and following proper establishment procedures. Today’s blog is a revised Iowa State University extension publication on establishing a lawn from seed. 

The following is a small introduction to the publication.

Time of Seeding

The best time to seed a lawn in Iowa is between mid-August and mid/late September. However, lawns can be successfully established as late as late-September in central Iowa and early October in southern Iowa. Late summer planting is preferred to spring seeding because seeds germinate and grow rapidly in the warm soil. The warm days and cool nights are ideal for seedling growth.

Establishment from seed in the spring is possible when irrigation is available. However, lawns established in spring often become infested with annual weeds unless preventive steps are taken. A pre-emergent herbicide such as siduron or mesotrione should be applied to the area during a spring establishment. Most of these preemergent herbicides kill the seeds of the cool season lawn grasses and cannot be used at the time of seeding. Mesotrione and siduron are the only exceptions. Siduron can be applied to areas seeded with Kentucky bluegrass, fine and tall fescues, and perennial ryegrass. Siduron selectively control weedy annual grasses, such as crabrass, foxtail, and barnyardgrass, while allowing the desirable turfgrasses to grow. Siduron is the active ingredient of many crabgrass preventer/starter fertilizer materials. Once the barrier of siduron has been established, the soil should not be further disturbed. Wherever the barrier is broken, annual weeds will emerge. Mesotrione is labeled for preemergent use only on newly seeded Kentucky bluegrass lawns to help control crabgrass seedlings and other annual weeds.

The entire extension publication is attached in pdf form. To download the publication, click on the following link Establishing a Lawn from Seed


Tall Fescue Summer Performance

June 13, 2017

The last couple of weeks have been especially hard on lawns, athletic fields, and golf courses in parts of Iowa that have experienced high temperatures, drying winds, and a lack of moisture. Ideally turfgrass would receive around 1 to 1.25 inches of rain per week to stay actively growing. That has not been the case in many parts of Iowa. Kentucky bluegrass will go dormant to avoid the drought and will go off color. If the dry conditions persist, some turfgrass cover loss will be expected. Our research area is no different, we have several athletic field research plots which have not received adequate rainfall. The area's which were planted to tall fescue are still green and looking good. Another plot that looks good in these hot dry conditions is the HGT bluegrass plots. The pictures below are a good illustration of differences between turfgrasses on the same site and soil. Hopefully rainfall and cooler temperatures will bring relief for turfgrass in Iowa.  

Green tall fescue clumps in dormant Kentucky bluegrass
Picture 1. Green tall fescue clumps growing in heat stressed and dormant Kentucky bluegrass.

Green tall fescue turfgrass on the right of the picture and dormant Kentucky bluegrass turf on the left
Picture 2. Overhead shot of dormant Kentucky bluegrass (on the right) next to green and actively growing 'Revolution' tall fescue at the Iowa State Horticulture Research Station. 

Heat tolerant bluegrass is still green
Photo 3. Heat tolerant bluegrass maintaining a green appearance without irrigation at the Iowa State Horticulture Research Station in Ames.


Healthy turfgrass around a broken irrigation head
Photo 4. Healthy and unstressed turfgrass growing in a ring around a broken irrigation head.



September 11, 2014

One of the most useful skills that students learn in my undergraduate turf class is to help others identify weeds in their lawn.  I just finished this power point presentation for them this morning and thought that others might benefit from this.  Particularly if you are in the lawn care business.  I want to acknoledge Dr. Aaron Paton on Purdue for taking some of these pictures when he was a student here. a few years ago.

The power point should open when you click on the link below.





Sciarid Snake

July 9, 2020

Here is a new  for me, Nick Christians.   I have never seen one that I know of.   It comes from Dr. Donald Lewis, depatment of entomology, here at Iowa State University and one of my former students, Damian Richardson, who is now owns his own lawn care company in Des Moines, IA.  Dr. Lewis tells me that this is very rare and he has never seen one in person, but that he has had occassional call on it over the years. 

Here is Dr. Lewis's report on the insident.

Damian Richardson gave permission to use his photos in a Turf Blog if you are interested in covering a “sciarid snake” which is not a snake at all, but rather at mass migration by hundreds or thousands of fungus gnat larvae.  Damian mentioned extra watering in this area as a contributing factor.

Here is my reply to Damian. 

I’m jealous that you have seen and photographed a “sciarid snake” and I haven’t.  Lucky you!  The sciarid snake is a mass migration of fungus gnat larvae.  It’s not uncommon to see them;  it’s just that I have never been in the right place at the right time.  I have seen photos but I have never seen one in person.  It must be amazing to see so many fungus gnat larvae moving en-masse.

Sciarids are fungus gnats, small harmless gnats that develop as larvae in damp, decaying organic matter.  A few fungus gnats are common in houseplants, and they often abound outdoors in damp areas such as wet soil, under grass clippings and mulch.  Essentially anywhere with continuous moisture and organic matter.

I don’t know what causes the migration of fungus gnat larvae or where they think they are going.  But hundreds of gnat larvae are moving in unison, gliding on a thin layer of mucous they secrete.  I believe it is a dispersal activity that allows a large number to move in relative safety by literally sticking together and conserving moisture.  These long, rope-like migrations are very temporary.  No control is needed.

Here is a link to more information about fungus gnats:

Note that near the bottom on the page, under Remarks, they state; "Sometimes abundant enough to form a crawling mass of several inches across and several feet long, similar to armyworm migrations."  That is what you photographed.

More photos:

Fungus gnat larvae are very, very common outdoors under mulch and leaf litter and other similar places that are constantly damp.  The fungus gnats are harmless and beneficial (they are recyclers of organic matter in the ecosystem). 




Donald Lewis

We always appreciate unusual things like this.  Feel free to send them too us any time.  Pictures are always a good addition.

Since I posted this, I received a video from Mark Storby, golf course superintendent in Wisconsin, of a Sciarid Snake on his golf green.  See video above, thanks Mark.