TURF FERTILIZING

1
TURF FERTILIZING
Edited by Vincent Mannino, County Extension
Director Texas AgriLife Extension Service
2
Fertilizing Your Texas Lawn Introduction
continued

• This training will teach you how to best
  fertilize your lawn by considering
• Your Texas location and growing season
• Your grass species whether cool-season or warm
  season
• Soil testing to determine fertilizer selection
• The maintenance level and expected quality
• Whether in open sun or shade
• The Take Home Message Being able to tell a
  homeowner go to the garden center and pick the
  right fertilizer and apply it to your lawn in an
  environmentally sensitive seasonal program

3
What do I need to know to fertilize my lawn?
This one question is a puzzle of many pieces!
4
Most homeowners ask

1. Why should I fertilize my lawn?
2. What do I need know about my lawn (soil type,
   grass type, shade)?
3. What do I need to know about fertilizers?
4. How do I choose a fertilizer for my lawn?
5. How much fertilizer should be applied?
6. When should I fertilize when my lawn?
7. How often should fertilizer be applied?
8. What is this I hear about environmental issues
   and fertilizer application?

Lets try to answer these questions
5
Why should I fertilize my lawn?
6
Knowing the right ins and outs of how to
fertilize effectively almost always

• Is the basic component of having a quality lawn!
• Helps you apply appropriate amounts
• Helps favor root growth and unforced leaf
  growth and limits thatch buildup
• Uses water more efficiently
• Helps lawns better tolerate moisture stress

7
What do I need know about a lawn?A soil type,
grass type, shade
8
How can soil testing help?

• How?
• You find out what nutrients in your landscape
  soil are either deficient or in excess.
• Soil acidity (pH lt 7.0), alkalinity (pH gt 7.0)
  and salts
• You are provided with a recommendation
• It protects from over application of Phosphorus
  and possible movement with storm-water
• You will know what nutrients your soil needs, if
  salts are a problem and fertilize recommendation?
  
• Where can I get my soil tested?
• Contact your local County Extension office.
• Or visit the following web site. http//soiltes
  ting.tamu.edu

9
Most Important Part of the Test Nitrogen (N)

• Soil test usually indicates residual N in that
  can contribute to plant growth and potential
  water contamination
• However, nitrogen is best applied according to
  recommended annual programs.

10
Lets talk about the nutrient most often applied
- Nitrogen

• Nitrogen (N) is the nutrient required in the
  largest quantity and it is applied most often.
• Other nutrients can come along with the
  nitrogen in a complete fertilizer or they can
  be applied separately.
• Typical recommendation in irrigated situations
  suggest applying up to 1 LB of actual nitrogen
  per 1000 square feet per application.
• More may lead to excessive growth or too much for
  the plant to use (potential leaching)
• Individual applications added together make up
  the annual nitrogen rate applied to lawns grasses
• Grass type, lawn quality, and maintenance level
  are also important considerations in determining
  how much and how often you apply nitrogen
  fertilizer

11
Annual Nitrogen Recommendations For Low,
Medium and High Maintenance Lawns
12
Lawn Grass Type (species) LBS Nitrogen per 1000 sq. ft per year LBS Nitrogen per 1000 sq. ft per year LBS Nitrogen per 1000 sq. ft per year
Warm Season Grasses Low Medium High
bermudagrass (common type) 1-2 2-3 3-5
Bermudagrass (hybrid) 2-3 3-4 4-6
Buffalograss 0-1 1-2 NR
Carpetgrass 0-1 1-2 2-3
Centipedegrass 1/2 1 2
Seashore paspalum 1-2 2-3 3-4
St. Augustinegrass (sun) 1-2 2-3 3-4
St. Augustinegrass (shade) 1/2 to 1 1-2 2-3
Zoysiagrass 1-2 2-3 3-4
13
Shade

• Grow turf where you can grow turf
• Grow Ground covers where you cannot grow turf
• Fertilizer requirement is 1/3 to 1/2 less for
  shaded sites

14
What do I need to know about fertilizers.
15
Nitrogen recommendation is given in pounds of
actual nitrogen per 1000 square feet of lawn area
Any fertilizer can be used. Fertilizer may be
selected based upon a number of features
including the grade (numbers on the bag
N-P2O5-K2O) complete fertilizer or by nitrogen
source (readily available or slowly available)
More on this later
16
It All Starts With That Bag of Fertilizer

• The numbers on the bag are important!
• These numbers are referred to as the grade or
  minimum guaranteed analysis
• The numbers in order represent
• Nitrogen by weight
• Phosphate (P2O5) by weight
• Potash (K2O) by weight

17
How do I know what nitrogen products are in the
bag I am looking at at the Garden Center?

• Look at the other information on the bag
• It will tell you the sources of N in the
  container
• If slow release N sources are in the bag they
  will be listed.
• By the way slow release sources will cost more
  than readily available N sources.

18
Different forms of Nitrogen Fertilizer Which is
Which? The readily available N sources

• Readily Available N sources -
• Inorganic
• ammonium nitrate
• ammonium sulfate
• ammonium phosphates
• Organic Urea
• Response time to grass green-up is
• relatively short.
• Residual activity fairly quickly converted
• to available nitrate nitrogen. May last
• only 4 to 6 weeks depending upon rainfall,
• irrigation and clipping return
• Under good growing conditions these products may
  produce high leaf growth rates more mowing!

19
Different forms of Nitrogen Fertilizer Which is
Which? The slowly available sources

• Slowly available nitrogen sources in lawn
  fertilizers
• Slowly soluble IBDU
• Slow release
• Sulfur coated ureas
• polymer coated ureas
• Microbial release dependent
• (needs warm soil temperatures)
• Urea formaldehyde,
• Methylene ureas
• Methylol ureas
• Natural Organics
• Processed sewage sludge
• Response time to grass green-up is delayed and
  product dependent.
• Residual activity may last 8 to 10 weeks
  depending upon grass species maintaining color,
  precipitation, irrigation product and clipping
  return
• Less growth surges

isobutylidene diurea
20
Knowing how your fertilizer will respond so you
can use it properly!
All readily available nitrogen

• Nitrogen fertilizers sold can be
• All readily available N
• All slowly available N
• Or mixtures of readily available and slowly
  available N sources
• Often homeowner-type fertilizers are a mixture of
  readily available N and slowly available N
• Knowing what proportion of the nitrogen that is
  readily available and what if any is slowly
  available allows you to use nitrogen wisely!

All slowly available nitrogen
Readily available N
Slowly available N
21
Often fertilizer companies mix some readily
available N with some slowly available N in their
fertilizers.

• What is readily available
• What is WIN or slow-release

We will do some calculations on this later
22
Comparing Nitrogen Sources in Lawn Fertilizer
Nitrogen Source Category Nitrogen Source Category
Characteristic Slowly Available Readily Available
Response time slow quick
Burn potential low high
Application more seldom More frequent
Water solubility low high
Residual greater (varies) short
Cost high low
Leaching potential lower high
Surface runoff reduced potential higher potential
Note yellow are more related to water quality
issues
23

• Slowly available N in the fertilizer are stated
  on the label.
• In the fertilizer below some N is listed as WIN
  or water insoluble nitrogen - a type of slow
  release nitrogen.
• The percentage of the WIN nitrogen is 3.6 and is
  also stated on a weight basis.
• Therefore, 3.6 divided by 12 as is 30 - Thats
  Good!
• The other 70 is considered readily available
  nitrogen.

24
How do I choose a fertilizer for my lawn?
25
Dont let all those fertilizers confuse you!
22-3-4
26
Selecting that fertilizer

• In addition to N, soil test results say
• If you need phosphorus
• If you need potassium
• If you need calcium, magnesium and other
  nutrients.
• Select a fertilizer ratio to meet your soil
  needs, but to do so you will need to soil test!
• Find an analysis fertilizer that supplies what is
  recommended by soil testing
• Do not apply phosphorus if not needed
• And, soil test will tell the pH

27
(No Transcript)
28
Fert. Facts

• Nitrogen sources influence cost, but also turf
  response
• Fertilizer manufacturing process will affect cost
• Consider ease of spreading
• Only buy what is needed
• If you have not soil tested you may use a
  nitrogen only fertilizer until you can soil test
  (more later)

29
How much fertilizer should be applied?
30
The fertilizer bag says that it will cover 5,000
ft2 - do I need to know anything more than that?

• Most people do not know how many square feet of
  lawn they have.
• You know 1 bag will cover 5,000 ft2 .
• You know what the analysis is according to the
  bag.
• You do not know what nutrients the soil/plant
  actually need.
• Only testing will tell. Extension agents,
  specialist, fertilizer salesman are good at
  GUESSING recommendations.

L
W
Length X Width sq. ft.
31
Measure that lawn! You only need do it once then
you have it!

• 1st Step Measure your lawn to find out how large
  the turf areas are.
• The lawn area to the right would be the areas not
  taken up by the house, drive, walk, deck and
  landscape beds.
• The total lot size is 180 Ft. by 80 ft. 14,400
  square feet
• The lawn area will be less than the total lot
  size - we just need to find out how many square
  feet of lawn there is!

80 Feet
Landscape Plants
Deck
House
180 feet
Drive
Lawn
32
Measure that lawn! You only need do it once then
you have it!

• The total lot size is 180 Ft. by 80 ft. 14,400
  square feet
• Sketch the lot.
• Break up the different lawn areas and multiply
  length X width in ft.
• Keeping a record of each section of the yard can
  help you check your fertilizer application by
  section.
• Sections 1 through 5 are pretty easy.
• Lawn in areas 6 and 7 and to the left and
  right of the deck also need to be measured.
• Add up all lawn areas. This example shows 8,000
  square feet of lawn.

80 Feet
5
6
7
Deck
1
4
8
9
House
180 feet
Drive
3
2
Lawn
33
Back to That Bag of Fertilizer and Take Home
MessagesLets talk about the nutrient most
often applied - nitrogen

• Applying this to our example
• From our example we determined the lawn was 8,000
  sq. ft.
• 8,000 sq ft. divided by 1,000 sq ft means we have
  8 units of 1000 sq ft in our lawn
• To apply 1 LB of N per 1,000 sq ft to our entire
  lawn we would then multiply 1 lb N by 8 units of
  1000 sq ft to find out our whole lawn needs a
  total of 8 LBS of actual nitrogen.
• Now we learn how to use this information to
  purchase the right amount of fertilizer.

34
How much of this fertilizer do we need? Your at
the garden center looking at fertilizer packages
of different N concentrations

• Step 1 Know the rate of N that should be applied
  per 1000 sq ft of lawn area. We will use 1 LB N.
• More on this later
• Step 2 Use the number for nitrogen on the
  fertilizer package of choice (20 here)
• Step 3 Divide 20 (0.20) into 1 (rate) 5 lbs.
  per 1000 sq. ft. to deliver 1 LB. N.
• Step 4 Calculate the total for the entire lawn.
  If we have 8 units of 1000 sq ft in our lawn. If
  we need 5 lbs of product for each 1,000 sq ft
  that means that we should purchase 40 LBS of the
  product (5 times 8) and evenly apply over the
  lawn!

20 Nitrogen by Weight
35
Lets try with another fertilizer at the same
rate of N and the same size lawn!
12 N

• Step 1 1 Lb N per 1000 sq ft is our goal
• Step 2 12 is the N by weight stated
• on the label
• Step 3 Step 3 Divide 12 (0.12) into
• 1 (rate) 8.3 lbs. per 1000 sq. ft.
• Step 4 On 8,000 sq ft it would be 8.3
• Lbs of fertilizer product times 8 units
• of 1000 sq ft 66.7 LBS of this fertilizer is
  needed for the whole 8,000 sq ft lawn.
• Yet some P2O5 and K2O were also applied. The
  nutrient ratio here is 4 - 1 -2. So with our 1 lb
  of N we applied 1/3 LB of P2O5 and 1/2 LB of K2O
• Did we need that much? Only a soil test will tell
  us that!

36
The amounts of various types of fertilizers
required to apply certain rates of N per 1000 sq
ft
Fertilizer Analysis Pounds of actual nitrogen desired/1000 sq ft Pounds of actual nitrogen desired/1000 sq ft Pounds of actual nitrogen desired/1000 sq ft Pounds of actual nitrogen desired/1000 sq ft
Fertilizer Analysis 1/2 1.0 1.5 2.0
Pounds of fertilizer to apply above N rate Pounds of fertilizer to apply above N rate Pounds of fertilizer to apply above N rate Pounds of fertilizer to apply above N rate
6-2-0 8.3 16.6 25 33
10-10-10 5.0 10.0 15.0 20.0
12-4-8 4.1 8.3 12.5 17.0
16-8-8 3.1 6.2 9.4 12.0
20-0-16 2.5 5.0 7.5 10.0
23-3-7 2.1 4.3 6.5 8.6
28-0-12 1.8 3.6 5.3 7.2
31-0-0 1.6 3.2 4.8 6.4
38-0-0 1.3 2.6 3.9 5.2
46-0-0 1.1 2.2 3.2 4.4
These rates only for use with slowly available
N sources
37
When should I fertilize when my lawn?
38
What growing season zone are you in?

• When you start fertilizer application and when
  you stop depends on where you are in Texas
• It matters for both cool season and warm season
  grasses
• The goal is to fertilize when the grass is
  actively growing, and can best use the nutrients
• Explanation of growing season zones follow

39
Knowing the Growing Season in your part of
Texas is the first step in knowing when to apply
fertilizer

• The length of the growing season is roughly the
  time between the last chance of frost in the
  spring to the first chance of frost in the fall.
• The growing season indicates temperatures are
  warm enough for grass growth

40
Growing Seasons as determined by Spring and Fall
Frost Dates
Zones Last Spring Frost First Fall Frost
N Jan. 30 to Feb. 14 Dec. 16 to no freeze
W Feb. 14 to March 1 Dec. 1 to Dec. 16
SE March 1 to March 16 Nov. 16 to Dec. 1
S March 16 to March 31 Nov. 1 to Nov. 15
41
Fertilizingthe Warm Season Grasses

• Bermudagrass (common type)
• Bermudagrass (hybrid types)
• Buffalograss (only native grass)
• Carpetgrass
• Centipedegrass
• Seashore paspalum
• St. Augustinegrass (sun)
• St. Augustinegrass (shade)
• Zoysiagrass

42
First Spring Applicationto warm season grasses
about the time of last frost!
Zones Last Spring Frost Begin Spring Nitrogen If Needed
1 No Freeze to Jan.30 Jan 30
2 Jan. 30 to Feb. 14 Feb 14
3 Feb. 14 to March 1 March 1
4 March 1 to March 16 March 16
5 March 16 to March 31 March 31
6 March 31 to April 15 April 1-15
7 April 15 to May 1 April 15-30
43
Last application No later than 6 weeks prior to
the first fall freeze date
Zones First Fall Frost Late season ending point for Nitrogen
1 No freeze Nov 1
2 Dec. 16 to no freeze Nov 1
3 Dec. 1 to Dec. 16 Oct 15
4 Nov. 16 to Dec. 1 Oct 1
5 Nov. 1 to Nov. 15 Sept 15
6 Same as Zone 5 Sept 15
7 Oct. 15 to Nov. 1 Sept 1
44
Consider when, how often and how much in putting
together an annual nitrogen fertilizer program
for Texas lawns

• Soil test in winter to determine need for
  complete (P, K, Ca, Mg) fertilizers
• Project a total amount of N to apply per 1000 sq.
  ft/year. see table to follow
• Consider use,climate, soil type and growing
  season Charts to follow
• Schedule N applications during the growing
  seasons timing rate in LBS per 1000 Sq Ft

45
Annual Nitrogen Recommendations For Texas Lawns
Lawn Grass Type (species) LBS Nitrogen per 1000 sq. ft per year LBS Nitrogen per 1000 sq. ft per year LBS Nitrogen per 1000 sq. ft per year
Warm Season Grasses Low Medium High
Bermudagrass (common type) 1-2 2-3 3-5
Bermudagrass (hybrid types) 2-3 3-4 4-6
Bahiagrass 1-2 2-3 3-4
Buffalograss 0-1 1-2 NR
Carpetgrass 0-1 1-2 2-3
Centipedegrass 1/2 1 2
Seashore paspalum 1-2 2-3 3-4
St. Augustinegrass (sun) 1-2 2-3 3-4
St. Augustinegrass (shade) 1/2 to 1 1-2 2-3
Zoysiagrass 1-2 2-3 3-4
46
How often should fertilizer be applied?
47
How often should fertilizer be applied to Warm
season grasses?
Using the chart on Annual Nitrogen
Recommendations For Texas Lawns -It would be
appropriate to apply low annual rates of nitrogen
once in the spring, and if needed again in the
fall. -Split fertilizer applications are
recommended. -This may require 1 to 2
applications to apply 1 to 2 LBS of nitrogen per
1000 ft2/year. -Medium and high annual
applications will likely require additional
applications during the growing season.
-Supplemental N if needed should be when rain is
evident or irrigation can be supplied. .
48
What is this I hear about environmental issues
(water) and fertilizer application?
49
Environmental Concerns in lawn fertilization

• Nitrate leaching into groundwater
• Nitrate runoff in stormwater
• Phosphorus stormwater runoff into surface waters
• fate from over application, poor timing, not
  using soil tests to determine need for phosphorus
  in your fertilizer
• Take Home Message When the grass plant is
  actively growing it is very effective in taking
  up nitrogen applied at reasonable rates!

50
Conservation ProtectionWater Sources Water
Quality
Stormwater nutrient runoff risks are greater in
areas with high annual rainfall (eastern Texas).
Texas relies heavily on ground water
supplies.Where does your water supply originate?
51
AvoidMisapplication!
Keep fertilizer off hard surfaces (reduces direct
fertilizer runoff into water resources)
Not a good thing for the lawn!