Questions From The Plant Clinic: Pre-Emergent Herbicides in Lawns

This week in the Plant Clinic we had a question from a resident on what Pre-Emergent Herbicide he should use to take care of weeds in his lawns. Pre-emergent herbicides work by inhibiting the growth of seeds, keeping them from sprouting for a certain period of time. They must be applied before the seeds begin to sprout!

Can I get a recommendation on pre-emergent herbicides?

Which pre-emergent weed control you use is determined by what weeds you currently have in your lawn. In the previous e-mails I don’t see what type of lawn you are growing, so I am going to assume it is St. Augustine. Healthy, well maintained turfgrass is its own weed control as it can out compete many different weeds.

If you have struggled with control in the past though, there are chemical options on top of proper cultural practices. According to the Weed Management Guide for Florida Lawns found on UF’s website [here], there are several different chemicals that can work as pre-emergent herbicides on St. Augustine. Pages 7 and 8 of that document list chemical names and examples of brand names to look for. The paragraph quoted below is the information on which chemicals work for which type of weed. I have bolded the chemical names so they are easier to find.

“In established turfgrass, members of the dinitroaniline herbicide family (e.g., oryzalin [Surflan], benefin and trifluralin [Team Pro], prodiamine [Barricade], or pendimethaline [Pendulum, Pre-M]) control annual grass and some broadleaf weed species when applied prior to weed seed germination.

Bensulide (Bensumec) and dithiopyr (Dimension) also provide preemergence annual grass and broadleaf control.

Atrazine and isoxaben (Gallery) primarily provide preemergence control of broadleaf weeds.

All these herbicides must be activated with irrigation or moderate rain within 2 days after application so they will be in direct contact with the germinating seeds and emerging weed seedlings. If the soil is dry, their weed-killing effect is greatly limited. On the other hand, if the turf is over irrigated, most pre-emergence herbicides will be moved below the soil layer where the germinating weed seeds are, reducing weed control.”

In that list above, the chemicals currently available to Home Owners are oryzalin (Surflan), benefin+trifluralin (Team Pro, Team 2G), pendimethalin (Pendulum, Pre-M, Halts Crabgrass Preventer), bensulide (Bensumec, Weedgrass Preventer), and Atrazine (many brands have this one).


Contact the Plant Clinic

The Seminole County Master Gardener Plant Clinic is open Monday – Friday from 9am-Noon and 1pm-4pm. For more information on how to contact a Master Gardener about your gardening questions, visit our website at this [LINK].

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Posted: January 31, 2018


Category: HOME LANDSCAPES, Lawn
Tags: Herbicide, Kaydie McCormick, Lawn, Questions From The Plant Clinic, Weed Control


Comments:

Morgan Pinkerton

January 10, 2022

Hi Bruce, There is quite the diversity of farms in Seminole County! Many of these farms are private or do not market their products direct to the consumer. These are some of those farmers and markets that are accessible to the consumer. If there are other farms that you think should be added to the brochure, please let us know! We update the brochure annually and we would love reach out to any farms or markets that we are missing :)

Bruce Macdonald
January 10, 2022

400 turned into 33 entries

Morgan Pinkerton

December 2, 2021

Hi Cindy, There are lots of local community groups that work on invasive species. I am located in Seminole County and I know of a few. One I work with regularly to host educational opportunities is the Central FL CISMA. I would check out their Facebook page for upcoming events: https://www.facebook.com/CFCISMA. The Cuplet Fern Chapter of the Native Plant Society focuses more on native plant species and sustainability so that might be another group to look into: https://www.facebook.com/cupletfernfnps.

Cindy Talley
December 2, 2021

Good Morning, Sustainability is important to me and I was trying to see if there are any local community groups you may be aware of related to this topic? I appreciate if you have any insights you could point me to a group I could learn and participate in future activities. Thank you, Cindy

Karen Henry

September 13, 2021

Thank you so much for your question. Information on how to join 4-H may be found at:http://www.seminolecountyfl.gov/4-H. We'll also send some information to you via email. :)

jaqueline araujo pontes costa
September 13, 2021

Hi. How can I enroll my daughters in a 4H club?

Mohammed Alharbi
August 3, 2021

As consumers, we want to know more about food and where it comes from. The farm tour video is the perfect way for viewers to get to know a dairy farming family. Take your students on a virtual field trip with these teacher-approved destinations, videos, and resources.

Morgan Pinkerton

May 7, 2021

Wonderful! I am glad you got to see something new. Thanks for your feedback :)

Priscilla Rose
May 7, 2021

I looked at all 6 even though I've been to at least 3 of the farms. The bee video was totally new and I found it particularly interesting. Thanks for the tours for 2021.

Morgan Pinkerton

May 3, 2021

You are very welcome! Thank you for bringing to my attention that the closed captioning wasn't working properly on the beef video. I think I got it fixed, but if you have any issues, please let me know :)

Noel Kohr
May 3, 2021

Wonderful presentation and thank you for the closed captioning on all but the beef. Very helpful for me, being hearing impaired.

Morgan Pinkerton

May 3, 2021

I am happy you enjoyed the videos! Thank you for your positive feedback. It was a really fun time putting them together.

Zalpha Hashem
May 1, 2021

These farm tour videos are great. Very informative and fun to learn and see the different local farms that we have. Even if you've been to these farms, these videos are fun education about them. Thank you for coordinating and putting these together.

Morgan Pinkerton

April 27, 2021

Thank you very much for your wonderful feedback! It is incredible the work our farmers do in our own county. We appreciate you sharing the information with others :)

Amy Lam
April 27, 2021

Thank you Morgan for the wonderful and educational farm tours! I watched all six tours! Love them! I do not know that cow is one of the local farm here in Florida! I will pass on this wonderful informational link to my Seminole friends. Thanks again!

Morgan Pinkerton

April 23, 2021

Thank you for your kind words. I am very glad that you enjoyed the virtual farm tour videos!

Dorothy
April 23, 2021

It was very interesting learning more about Florida agriculture. Like the virtual tour as could go back and watch again to remember more.

Morgan Pinkerton

October 23, 2020

Hi Gary, Thank you! This is something we may do in the future! UF/IFAS also has a lot of EDIS documents that are great resources for different fruit trees. If you haven't heard of our EDIS documents before, I would recommend checking them out. You can visit the EDIS homepage here: https://edis.ifas.ufl.edu/. The website allows you to search for specific topics that you are looking for. There are documents on lots of different things including some recommendations for growing different fruit trees.

Gary
October 22, 2020

Really well put together Dr. Morgan. Will you ever have a follow up on any specific fruit tree(s) that people have trouble growing here in Florida?

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Kaydie McCormick

August 3, 2020

Hi Evelyne! This will entirely depend on the spray you plan to use. Read the label. It will tell you if it is safe to eat the fruit after spraying, if it should be sprayed a certain number of days before harvest, or if it is not safe at all to use on your tree. Hope that helps! Kaydie

Morgan Pinkerton

July 31, 2020

We appreciate you sharing this message with others! The seed packets could be a risk to our agriculture and natural resources and we hope that others will take the message as seriously as you.

Charlene Reiff
July 30, 2020

OMG, Thank you for exposing this! I just clicked on this to read about it from a person putting it on Facebook! I havent received any seed package and will definitely try my best to get the word out concerning this. I know about the horribly invasive plants, reptiles, etc, and the havoc they are causing . Hopefully we can catch this right away . And if we can catch the perpetrators,and severely punish them, all the better! Good Luck!

Marilyn Strout
July 28, 2020

I planted Bambusa Guangxiensis "Chinese Dwarf" "China Doll" in a blank area in April 2019 Zone 9B Daytona. Within 6 months most of the neighbor was blocked, but now, at 15 months in he has disappeared from sight! I am thrilled. China Doll is a very dense, bushy, large leaf bamboo that provides a quick hedge with it's lush foliage. Will grow up to 20 feet, but easy PRUNING to any desired height makes this one a great choice for blocking an area from view. Plentiful leaves add to its unique beauty. It's good for cooler areas to about 26F

Morgan Pinkerton

June 16, 2020

Thank you! I am very excited to share what I know with you.

John Ullom
June 16, 2020

Congratulations Morgan! I now can be your student. My recent interest in gardening has made me aware of all the good work you and your fellow extension agents do! I will be doing my best to follow you as you begin your career!

Evelyne Laurevil
June 15, 2020

Hello Kaydie, I am experiencing infestation of mealybugs on my papaya tree; I had to throw some papaya fruits out because I even found maggot inside before ripened. Should I remove all fruits before spraying with fruit insect spray?

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Hannah Wooten

June 11, 2020

You bet! Find your agent here: https://sfyl.ifas.ufl.edu/find-your-local-office/

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Hannah Wooten

June 11, 2020

Hi Stefanie, It is best to work with a professional for diagnosis. If you send your local Extension Agent food photos, that can tell us a lot. If we suspect something more, we will recommend taking trunk samples, which again, is something you should work with a pro to do. It involves opening a wound directly into the tissue of the tree, and if not done properly, could be an invitation for disease.

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Hannah Wooten

June 11, 2020

Hi Lauren, the best practice is to replace with something different that is not susceptible to the disease.

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Hannah Wooten

June 11, 2020

Hi Janice, yellowing fronds are typically an indication of a nutrient deficiency which can usually be corrected with a good palm fertilizer for Florida. The diamond cut should be okay whether done before or after transplanting, but in general, we do not recommend pruning off palm fronds that are alive... only prune off dead brown fronds. This will prevent the opportunity for a disease to enter an open wound.

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Hannah Wooten

June 11, 2020

Hi Bill, Can you send me some pictures to hwooten@ufl.edu?

suba suba
June 11, 2020

Wow! This can be one particular of the most useful blogs We ave ever arrive across on this subject. Actually Magnificent. I am also an expert in this topic so I can understand your effort.

WILLIAM(BILL) KLEIN
May 23, 2020

Any thoughts about a central spear leaf yellow, but not (yet) brown or bottom fronds browning?? Two years after transplanting two ten ft sylvesters. Ugh. Thanks, Dogtorbill

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Kaydie McCormick

May 14, 2020

Hi Darryl! I would recommend reaching out to the Marion County Museum of History and Archaeology to see if they can provide some help. I looked up their website and you can find it here: http://marioncountyarchaeology.com/mcmha/mcmha.htm Thank you for reading and good luck in your search!

Darryl marietta
May 13, 2020

Love this article. My wife and I have recently bought Mr. Frank Sampsons orginal home in boardman and are in the process of restoring it to original. We have found lots of history on the home and property but the one thing we cant find is actual pictures of the home and packing house. Any help would be greatly appreciated. Thank you

Janice Freeman
May 10, 2020

We are in the market to purchase a sylvester palm. What should we look for to identify a healthy palm? We have seen many with yellowing fronds. Are yellowing fronds an indication of a problem? Is it better to purchase a palm with a diamond cut trunk or better to have the diamond cut done after planting in our yard?

Lynne
April 11, 2020

Good to know

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Kaydie McCormick

March 23, 2020

Hi Sallie! I don't keep rabbits, and there isn't a central repository list of plants to check, so I asked our livestock agent, JK Yarborough (you can find his blog profile by clicking here). He let me know that as far as he is aware, dollarweed isn't toxic to rabbits, though he isn't sure if they'd have a preference for it over other things. If your rabbit accidentally eats some dollarweed, however, it isn't something to worry about. Hope that helps! Kaydie

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Kaydie McCormick

March 23, 2020

Thanks for the correction Mari! =)

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Kaydie McCormick

March 23, 2020

Hi Lindy! It spreads both by seeds and by its underground rhizome (those thick white stems/roots underground). If the rhizome is moved (say by mower blades) from one area to another it can spread that way, otherwise it will spread by seed.

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Kaydie McCormick

March 23, 2020

Hi Keya! When I have tried to smother it in the past I have had mixed results. You could probably smother it with a thick layer of cardboard, but no guarantees it will not come back. Hand pulling can work if you get the whole root system up - but that can be difficult as well. Changes in your cultural practices can also slow it down - dollarweed usually likes a wet area, so if you can reduce irrigation or improve drainage, that might slow its growth in your garden. There are a lot of chemicals that can be used to treat for it, but if you can try to change the water, smother it, or handpull, that would be the safest option. You can find UF/IFAS's recommended chemicals for control of dollarweed here: https://edis.ifas.ufl.edu/ep389

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Kaydie McCormick

March 23, 2020

Hi Sims! According to our UF/IFAS Website on crabgrass control, the time for pre-emergent application has already passed (back in February). They do have a list of both pre and post emergent herbicides to use on their website however. You can find the website at this link: https://edis.ifas.ufl.edu/ep395 The easier to read PDF version of the website is at this link: https://edis.ifas.ufl.edu/pdffiles/EP/EP39500.pdf In order to remain unbiased, only the chemical names have been provided, with no trade names. You'll have to look them up to see what brands are actually using those active ingredients. Let me know if you have further questions! Kaydie McCormick

Sims Hagan
March 22, 2020

I live in South Florida, and I am wondering about a pre-emergent for our St Augustine in particular to prevent crab grass from seeding. Is there one that I can recommend to our professional chemical guy and one that I can use myself as a homeowner? If yes to both, when are the best times to put them down? I am a snow bird, and we always put pre-emergent down in March up north, but our lawn care professional in Boynton beach has never heard of a pre-emergent for St Augustine. Yikes! Hard to keep up is we are doing nothing preventative down here, I think. Many thanks!

Sallie
March 8, 2020

Can rabbits eat dollar weed?

Keya K Archie
March 1, 2020

What makes dollar weed go away can I smother it out? What can I do??

Lindy Magadad
February 19, 2020

How does dollarweed spread?....Does that small pink flower that grows from a clump release seeds that spread around by the wind or run over by a lawnmower? Does the Bulb split and a new sprout happens?

Mari
December 23, 2019

Love the article! One little note, dollarweed is in the Apiaceae family, Hydrocotyle species

Bonnie harrison
December 19, 2019

Great article. Marie Spoon is an inspiration for us all.

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Kaydie McCormick

November 15, 2019

Hi Hava! Dollarweed is not a parasite (it doesn't steal nutrients directly from other plants) but it does compete for nutrients in the soil, just like all plants do. If it is better able to take up nutrients than a flowering plant - instances where soil conditions favor the dollarweed over the flowering plant would help with this - then it could possibly outgrow the other plants in a garden.

Hava Laor
October 19, 2019

Is dollar weed hurting flower plants? Is like a parasite living off the plant and using its nutrients?

Lauren G
October 16, 2019

I had a Sylvester palm planted almost 6 months ago that is suffering with this disease. Our llandscapers who planted the tree are going to replace it with another Sylvester. But I’m a little concerned, will the next one suffer the same fate being planted in the same hole? What are my best options for the new palm tree to thrive? TIA

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Kaydie McCormick

August 12, 2019

Hi Audrey! It is not a problem I have encountered before! As this is a pretty commonly eaten plant, it might be an allergy unique to just a few, or it could be something else in the soil that is causing your skin problems. I'm not a doctor though, just a plant nerd, so you might want to speak to a medical professional about it if it becomes a lingering problem. Thanks for reaching out! Kaydie

Audrey R Young
August 5, 2019

Has anyone ever developed blisters from hand weeding the roots? I seem to every time I dig deeply to remove the long, white root.

reclinersinfo
May 9, 2019

Thanks for this great stuff to write.

Randy.gillespie
April 27, 2019

Ihave two selvester palms about 8foot tall and they both have trees i the ground for about 3 mounths. They are loseing tree branches layer by layer .iv done everything. Inow and still turning brown.if you have someone locol that i can talk to would be very much appreciated my numer is 561 #######. My name is randy gillespie i am in west palm beach.if you have any body i can hire. Or look at these trees i will defiantly take care of them.idont want to lose these tree's. Thanks or email this. Address back.

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Kaydie McCormick

April 11, 2019

We hope so Joe! Starting a school garden is a large undertaking that needs plenty of hands helping to get started.

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Kaydie McCormick

April 11, 2019

Thank you Nancy! We are so happy to have a great partner like Marie working with us at a school!

Nancy Ruppert
April 9, 2019

Thank you for this wonderful story. Marie Spoon is my sister and for this garden effort (and so many other reasons), I am indescribably proud of her!!

Joe
April 4, 2019

Great story that should embolden other schools to heed the educational pluses of gardening...

Stefanie
March 1, 2019

How do we do the test for diagnosis of TPPD? We have three Sylvester’s just installed in August 2018 and two appear to be on their way out.

Heather Rizzi
February 15, 2019

Hello, I am the president of Bonafide Landscaping. I have a dear client that it appears has this Texas Phoenix Palm Decline aka TPPD. I have had multiple arborist look at her palm to try and help save it. I came across this and would love if I could ask for help. She has a beautiful Palm and would loose such a great house curb appeal if this palm dies.

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hwooten

January 17, 2019

Hi Chris, That is interesting and thank you for sharing! I wonder what the status will be in another 10 or 20 years? Can we get a follow up in 2029? Very best!

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hwooten

January 17, 2019

Hi Terese, Palms that are surviving with TPPD can be treated with Oxytetracycline (OTC) trunk injections for the rest of the life of the tree. This could get expensive, so I would recommend evaluating the value of the tree and whether it is worth treating for the remainder of its life. Palms come at all different price tags! Best of luck!

Chris Garrett
January 17, 2019

I have been treating palms for quite a while in Orlando, I've seen a lot. I've even seen a Canary expire from Ganoderma (no mistaking those conchs) then same spot replanted with Sylvester, no soil change out and it has been doing well for 10+ years...go figure!

Terese DeLuca
January 15, 2019

where do you get the treatment for TPPD of which our landscaper has diagnosed our tree having this problem. Can this treament be done by us the homeowner or do we need to hire a landscaper to apply the treatment and what exactly is the process etc. We read the articles and testing menthods done but done have contact info on purchasing the product.please advise

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Kaydie McCormick

December 28, 2018

Hi Brenda! It is nice to see someone else interested in the topic! This article was written by one of my former Master Gardener Volunteers, Kevin Said Jardaneh. He had a huge interest in the history of agriculture while he lived here in Florida. Unfortunately he moved to Oregon this summer. He did all of the research for this article - I just edited it and posted it for him. The only contact information I have for him is in the article. As he left UCF to pursue a position at a university in Oregon though, I'm not sure you'll be able to reach him there: jardaneh@knights.ucf.edu Kaydie McCormick

Brenda Eubanks Burnette
November 13, 2018

Hi, Kaydie - I enjoyed your article very much and wish you would do more research on Sampson and a multitude of other growers who, as you've noted, are absent from the Florida Citrus Hall of Fame. Like most other organizations of this kind, people have to be nominated and then voted upon for induction. The people who are willing to take the time and effort to do the research and submit those nominations are few and far between. People are quick to note that someone is not listed who should be included. However, without that effort, our committee has no information to review. You will be happy to know that Jo Kean submitted a nomination packet on Mr. Sampson, and he is up for review again. However, the information that she sent left out several key components which you reference in your article. I would like to obtain this additional information to either add to his packet for next year's consideration or hopefully use should he be chosen this year. Either way, I hope you will send out a call for action to other researchers and help us get more of our forgotten pioneers like Mr. Sampson on our ballot! Thank you for helping others rediscover our citrus heritage! All my best - Brenda Eubanks Burnette

Paul
November 10, 2018

Is there someone in manatee county as well?

Lee Breedlove
October 3, 2018

Great article! Thank you.

Bonnie Pogorzelski
September 18, 2018

I live in Altamonte Springs and have a "large family" of honey bees that now have a have filling my wood duck house. I planted lots of wild flowers to attract the ...and I did. I really need someone to come and relocate them.

Mike
September 9, 2018

Hydroponic gardening methods are a great way to provide fresh produce to the inmates at a low cost. More correctional facilities should incorporate programs like this which would ultimately reduce costs to taxpayers.

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Kaydie McCormick

September 4, 2018

Hi Sarey! It took a little while to find a research paper discussing this, and unfortunately I can answer for a relative in the same Order, Centella asiatica, but not for our native dollarweed, Hydrocotyle bonariensis. They likely have similar, but not identical nutrient content. It would be an interesting study to conduct, as ethnobotany and utilizing plants we consider weeds in the garden is an emerging field of study and becoming more popular among the general public! "Leaves of the Asiatic pennywort are 87.7% moisture and 2% protein on a fresh weight basis (16.26% dryweight), 0.2% fat, 6.7% carbohydrate,1.6% fiber, and 1.6% ash (Bautista etal., 1988; Zanariah et al, 1986). Fresh leaves are an excellent source of vita-min C, containing about 7 mg/100 g(Gunasekara and Ravindran, 1989) and contain 738 IU of vitamin A and 0.09mg of vitamin B 1/100 g fresh edible material (Bautista et al., 1988). When the leaves are allowed to wilt, however,95% to 99% of the vitamin C is lost(Kailasapathy and Koneshan, 1986).The plant is also a relatively good source of the minerals Ca (171 mg/ 100 g edible), P (32), and Fe (5.6)(Bautista et al., 1988; Jayaweera, 1982;Turton, 1993). Leaf composition varies somewhat with location." Excerpted from: http://www.academia.edu/19351641/Asiatic_Pennywort_Centella_asiatica_L._Urb._A_little-known_vegetable_crop

Sarey
September 3, 2018

Hi, What nutritional value does dollar weeds provide? Sarey

Barbie
July 29, 2018

Hi, My name is Barbie. My 15 year old niece wants to be a veterinarian and I just came across this camp. Can you send me some info for us to look into this next year?

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hwooten

July 18, 2018

Hi John! It never hurts to reach out to your local UF/IFAS Citrus County Extension Office for some guidance on diagnosis and treatment. Here is their email: citrus@ifas.ufl.edu I would get a confirmation of diagnosis of TPPD as treatment is not cheap and it is continual. Good luck with your sylvester palm!

John Stoppelli
July 18, 2018

I believe I also have a Sylvester palm that may be suffering from this disease. I live in Citrus Cnty. . I have ordered the treatment for the disease mentioned which will arrive tomorrow. Sad to think it may be to late but I will try and hope for the best.

Deborah Thomas
October 29, 2017

I appreciate the info. The more l know, the better l can treat my space. Thanks for the tips.

Heidi
October 28, 2017

I love this, I have been doing this for years! Never waist good yard waist. My moto!!

celana sirwal
October 23, 2017

Keep this going please, great job!

dani
August 16, 2017

"I really like your writing style, good info, thanks for posting. “Let every man mind his own business.”

cwoodard

July 18, 2017

Thank you for the comment Brooks. Which post are you referring to? I'd be happy to answer any questions you have about 4-H and our programs.

dani
July 18, 2017

"Greetings! Very helpful advice within this post! It is the little changes which will make the greatest changes. Thanks for sharing!"

Brooks
July 18, 2017

magnificent issues altogether, you just gained a emblem new reader. What may you recommend about your publish that you made some days ago? Any certain?

cwoodard

July 10, 2017

Thank you for your comment. Our UF/IFAS Extension Seminole County Blog is relatively new. 4-H will be posting approximately once a month. Our other program areas (Horticulture, Agriculture, Family and Consumer Science) will begin posting this fall. Sincerely -Chelsea Woodard

COOLSEO
July 8, 2017

I have been absent for a while, but now I remember why I used to love this site. Thank you, I will try and check back more frequently. How frequently you update your web site?

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