Fall Lawn Care
Contrary to popular opinion, fall is the best time of the year
for lawn care. Fertilization, weed and thatch control, establishment
of new lawns, and renovation of poor quality lawns should be done
over the next few weeks.
The best time of the year to fertilize your lawn is early fall.
Northern Illinois lawns are usually a combination of Kentucky bluegrass
and perennial ryegrass. These cool season grasses grow rapidly in
spring and fall. If you only fertilize once a year, the best time
to do it is around Labor Day. For a moderate quality lawn, apply
fertilizer May Day and Labor Day. High quality lawns should be fertilized
May Day, Labor Day and Halloween. Very high quality lawns that are
watered all summer may also be fertilized around Father's Day.
Top quality lawn fertilizers contain slow-release or controlled-release
nitrogen. Look on the label for slow-release forms such as ureaform,
sulfur-coated urea, milorganite, and IBDU. These forms stimulate
uniform growth over a period of time and are less likely to burn
the grass. However, do not expect the quick green up caused by fast-release
forms. Slow-release formulations are more costly but worth the price
for the improved health of your lawn.
In early fall use a regular lawn fertilizer with N-P-K ratios of
3:1:2 or 4:1:2. For example, a bag may list 21-7-14 or 32-8-16.
Amounts don’t need to be exact but should be similar to the
suggested ratios. Hold off on applying "winterizer" fertilizers
until late October or early November.
Kentucky bluegrass and perennial ryegrass lawns in sun should receive
1 to 4 pounds per 1000 square feet of actual nitrogen every year.
A rate of 1 pound of nitrogen per 1000 square feet is recommended
for each fertilizer application. Lawns and other plants in shade
grow slower and don't need as much nitrogen as plants in full sun.
Therefore, shady lawns should be fertilized at half the recommended
A little math will show you how much fertilizer you need to put
on the lawn to get 1 pound per 1000 square feet. Divide 1 by the
first number in decimal form (percent of nitrogen) on the fertilizer
bag. Multiply that by the square footage of your lawn, then divide
by 1000. The answer will give you the total pounds of fertilizer
you need to apply to the lawn.
Here’s an example: you have 15-5-10 fertilizer and a 7000
square foot lawn. One divided by 0.15 equals 6.7. Multiply 6.7 by
7000 for 46,900. Then divide by 1000 for the answer of 46.9 or 47
pounds. So you would need to put 47 pounds of 15-5-10 spread over
the entire lawn to properly fertilize it.
September and October are the best months to control perennial
broadleaf weeds like dandelions and clover. In autumn the weeds
prepare for winter by pulling nutrients and starches from their
leaves into their roots. By doing this, they also draw herbicides
into their root systems, thus more effectively killing the weed.
Actively growing grass will quickly fill in the bare spots created
after the weeds die.
Thatch is a build-up of living and dead grass roots and stems between
the soil and green grass blades. The amount of thatch in the lawn
may be checked by cutting three to four inches down into the grass
with a shovel and lifting up a piece of sod. Thatch looks like a
thick tangle of dark brown roots above the soil level. If thatch
is greater than 1/2 inch, the lawn should be core aerated or dethatched
in fall or spring. In lawns with a thatch layer over 3/4 inch thick
you should aerate then topdress with a thin layer (1/8 to 1/4 inch)
of soil or compost. Topdressing adds microorganisms that help breakdown
The ideal time for planting grass seed to either establish a new
lawn or renovate a poor quality one is the middle of August to the
middle of September. During September grasses grow rapidly in the
cool fall weather and have less competition from germinating weeds.
Whether seeding or sodding, the key to long term lawn quality is
proper soil preparation. Soil should be tilled six inches deep.
Incorporate organic matter, such as compost or peat, when tilling.
If soil test results indicate a soil pH problem, sulfur or lime
should be added at this time. After tilling smooth with a rake and
apply starter fertilizer.
Top quality grass seed will germinate better and be more disease
resistant over time. Newly seeded lawns must have adequate moisture
for seed germination and seedling growth. The seedbed and later
seedlings must be kept moist for six weeks.
Although many people consider fall a time to relax and watch football
on television, don’t pick up the remote until the lawn care
is done. Next year’s lawn will be the better for it.
August - September 2002:
Purple Plants Can Be Pesky
Rust Diseases on Home Lawns | Spring
Late Summer ‘Do’s and ’Don’t’s
| Fall Lawn Care