Question:
Teressa - St. Petersburg FL
I just put SeaIsle 1 sod and some plugs down at the end
of June, and it did really well for a couple of weeks,
but now more than half of the lawn is brown in large
patches. There are a few green stems still hanging on
throughout the lawn, and I at first thought we had
scalped it. However, this morning I was able to see tiny
webs throughout with the dew still on them. Can you
diagnose the problem and suggest a solution?
Answer:
Seashore Paspalum is a preferred food for a couple of
worms that basically defoliate the leaf tissue. It sounds
like that's what you have. Do the leaf tissues look
they've been chewed off, with remaining tissue still
green? If so, you will need to spray with an insecticide.
There are a number of products you can use, including
Sevin, Talstar, Merit. Be sure to follow label
directions. Once the insects are controlled, the grass
will grow back. Fortunately, it grows rapidly this time
of year. Another problem that sometimes occurs with
Paspalum is disease- if the shoot tissue looks brown and
torched, it can be disease. This sometimes occurs in
response to scalping, which you mentioned, or over or
under-irrigating. You want to make sure you're treating
for the right thing, as this would need a different type
of chemical control. If you suspect disease, you should
submit samples to a diagnostic lab.
Laurie E. Trenholm, Ph.D.
Urban Turfgrass Specialist
University of Florida
P.O. Box 110670
Gainesville, FL 32611
352-392-1831 ext. 374 Question:
Brian - Jacksonville FL
Could you give me cold weather management
instructions for my SeaIsle 1 lawn?
Answer:
Depending on where you are in Jax, you may or may nor go
through much dormancy. If you're near the ocean and St.
Augustinegrass lawns stay green, yours probably will too.
If everyone else goes dormant, SeaIsle will too, but
generally about 2 weeks later than St. Aug. However, in
general, you will want to let the lawn slow down growth
in response to shorter days regardless of temperature.
This means that you reduce all inputs: fertility, mowing,
irrigation. Around the end of Sept. I would apply a
fertilizer treatment (something like a Lesco 15-2-22)
with high potassium (3rd number on bag). Put it out at
about 1/2 lb. of N per 1000 square feet of lawn (that
equals about 3.3 lbs. or 7.25 cups of this fertilizer per
1000 sq. ft.). The potassium will help somewhat in
overwintering and spring green-up. Your mowing needs will
be greatly reduced for much of the winter and be sure not
to remove much tissue at any one time. Paspalum is VERY
sensitive to scalping, or removal of too much tissue.
Irrigation needs change tremendously in the winter- you
can generally irrigate every 2-3 weeks with about
1/2" of water each time. This will keep the roots
functioning all winter, which will also help in spring
green-up.
Laurie E. Trenholm, Ph.D.
Urban Turfgrass Specialist
University of Florida
P.O. Box 110670
Gainesville, FL 32611
352-392-1831 ext. 374
Question: Larry - Corpus Christi TX
We are strongly considering SeaIsle for our new coastal
home as an alternative to St. Augustine. Our lot is
essentially beach sand. Can we expect good results if we
sod over sand, or should amendments be incorporated
first? Also, we have a couple of small dogs. Will their
urine cause damage to the turf once established. For
info, they didn't cause any apparent damage to a St.
Augustine lawn.
Answer:
Any grass will do better in amended or heavier soil than
in beach sand. This type of sand has little water or
nutrient-holding capacity, meaning that inputs need to be
higher. I don't know if it's feasible to amend enough to
change the soil characteristics- but some amendment would
not hurt. Damage from dog urine is generally minimal-
it's the highly soluble urea nitrogen in urine that
causes a burn in some cases. Paspalum is very good at
taking up fertilizer, and although you might see some
mild injury symptoms, it will quickly outgrow them. It
will also hold up to traffic from the dogs better than
St. Augustine grass
Laurie E. Trenholm, Ph.D.
Urban Turfgrass Specialist
University of Florida
P.O. Box 110670
Gainesville, FL 32611
352-392-1831 ext. 374
Question: John - Jacksonville FL
We recently sodded SeaIsle1 and it did well for about
4 weeks then became sparse/died mostly along the tree
line.I know it is not shade tolerant, what is the minimum
# of hours of sunlight needed? What brand of fertilizer
do you recommend from the local hardware store? When can
I plant plugs to help fill in the dying areas? Would
spraying with magnesium help? Thank you.
Answer:
When you refer to "sparse/died", what are the
symptoms- did it go yellow or brown first, is there still
some green shoot tissue? The number of hours of sunlight
needed will vary somewhat depending on intensity of
sunlight. Would you estimate that the shaded area has 30%
shade, 50%, or more? Paspalum generally needs somewhere
around 5-6 hours of sunlight daily for best growth, but
it will grow with less than that if it gets full sunlight
the rest of the day. Grass growing in shade needs
different cultural care than grass in full sun. These
include:
* less fertilizer- you don't want to force it to grow
more in shade as it depletes carbohydrates trying to stay
alive in shade
* less water- water requirements and use are less in
shade and you want to reduce potential for disease
development
* higher mowing height- the grass will grow taller in
shade, so don't scalp it and force it to regrow
This translates to applying roughly 2-3 lbs. of actual N
per 1000 sq. ft. yearly, preferably in 3-5 separate
applications. In NE FL, you would apply fertilizer from
early April through Sept. Paspalum responds well to
fertilizer (meaning it grows!) and smaller amounts more
frequently are best. It also like potassium (3rd number
on the bag). I would suggest going to the Lesco retail
outlet store and looking for their 15-2-15 or 15-2-22.
Apply this at about 1/2 lb. N per 1000 sq. ft. This would
be ~3.3lbs. of fertilizer (or 7.3 cups) per 1000 sq. ft.
each time you fertilize.
You can plant plugs in the bare areas anytime from now
till Sept. They will grow slowly initially but will be
completely covered by next year. Fertilize them once or
twice with the same fertilizer at the same rate and you
will have cover in about 6 weeks. I doubt spraying with
Mg would help. Try the above fertilizer and see if it
helps
Laurie E. Trenholm, Ph.D.
Urban Turfgrass Specialist
University of Florida
P.O. Box 110670
Gainesville, FL 32611
352-392-1831 ext. 374
Question: Dale - Sanford NC
I planted Seaisle 1 plugs in late April and it has filled
in very well in the Sanford Clay. I have two questions:
(1) I have some nut weed and a little crab grass. Can I
use the new Ortho Weed be Gone for crabgrass/dallisgrass
& nutgrass killer? (2) I have been moving about and
1" to 1 1/4" and if I go any lower the place
where the plugs were becomes bare and burnt out looking?
I have been watering every other to every day depending
on the rain fall which has been very scarce this summer.
The grass has a lovely color and is spreading nicely.
Answer:
I don't know how much you are fertilizing with every four
weeks (do you know in lbs. of nitrogen [1st number on the
bag] per 1000 square feet?). It likes low fertility, so
applying that often is fine, but you want to only apply
small amounts each time you do fertilize, like around 1/4
to 1/2 lb. of nitrogen each time for about 4 applications
over the growing season. It's not much fertilizer! The
browning you experienced after mowing is common, and
results from "scalping" or removing too much
leaf tissue with one mowing event. Since the grass grows
readily in response to fertilizer, you may have
over-fertilized, causing excess growth, which means you
took off too much tissue at that time. This can lead to
disease problems or the grass may grow back. If the brown
areas spread and the grass is all dead, it's disease- if
it's growing back, as you have indicated, it was probably
just responding to the mowing and may be OK. If there is
a disease issue, you will need to have a fungicide
applied- you probably want to put out a broad spectrum,
systemic fungicide that will control many different
pathogens. You really should take a sample from an
affected area to the Cooperative Extension Diagnostic Lab
(you can find out how to contact them from your county
extension office) and they would issue a more precise
recommendation based on what disease they actually find.
However, if it grows back, you may not need to worry
about that. A key here is mowing- you may need to mow
more frequently or reduce your nitrogen, although you'll
find that growth of paspalum will slow greatly this time
of year. Most of the Ortho products are safe on paspalum,
but I'm not sure exactly what is on the label of the
product to which you refer. There are not many products
that will effectively control crabgrass once it has
emerged. We recommend a good "pre-emergence"
program, which means you apply the herbicide in the
spring before the weed germinates. Check with your local
extension office on when that would be in your area and
for what products they recommend. Worms of a couple
different types are a problem on paspalum. Any
insecticide labeled as effective for their control and
for warm-season grasses can safely be used on paspalum.
You may need to reapply.
Laurie E. Trenholm, Ph.D.
Urban Turfgrass Specialist
University of Florida
P.O. Box 110670
Gainesville, FL 32611
352-392-1831 ext. 374
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