How Long To Wait After Fertilizer Application?

Nullqwerty · Aug 20, 2013

Hey folks,

I've been trying to research the safety of fertilizer application and children playing in a treated lawn. Harder than I thought.

I know I can use organic fertilizer if I wanted to be ultra-safe. But lets put that aside. Assuming I'm using normal non-organic fertilizer, is there a general consensus as to how long after an application it becomes safe for children to play in the grass? Is it considered safe again after 24 hours or 48 hours or 1 week? Or is the idea that a lawn regularly/scheduled treated is never safe for children to regularly play in?

I am fine with saying to my kids "Don't play on the grass for the next 2 days" and am very confident it won't be a problem. It is a problem if I say though "The grass is never safe to play in kids". In that case, I'll go organic.

Thanks

FdLLawnMan · Aug 20, 2013

There is no restriction as to when people can enter an area treated with straight fertilizer. You are talking about nitrogen, phosphorous and potash. What is unsafe about those materials. Personally I think they are safer than dried human or cow waste.

greendoctor · Aug 20, 2013

I remember a daycare center specifically prohibiting "organic" fertilizers because of the possible pathogens and parasites present. Fertilizer watered in is not harmful to children or pets once the irrigation is dry. Chemical N, P and K is no more harmful than table salt. People do swim in the ocean, right?

phasthound · Aug 20, 2013

If the fertilizer contains pesticides, the label will provide the time of safe re-entry. For instance;

Precautions And Restrictions:
Do not apply this product in a way that will contact any person or pet, either directly or through drift. Keep people and pets out
of the area during application. Do not allow people or pets to enter the treated area until dusts have settled.

americanlawn · Aug 20, 2013

greendoctor said:
I remember a daycare center specifically prohibiting "organic" fertilizers because of the possible pathogens and parasites present. Fertilizer watered in is not harmful to children or pets once the irrigation is dry. Chemical N, P and K is no more harmful than table salt. People do swim in the ocean, right?

Organic... a general term. Natural? Synthetic organic? How synthetic? Any more, most companies that sell "natural" organic fertilizer synthetically modify their products.

"Natural" organic fert can contain dangerous pathogens, contaminants and hazardous dust particles.

Manure runoff often causes many lakes & rivers "off limits" for swimmers.

We stopped offering "natural fertilizers" some years back because we were concerned about health issues. We prefer to use professional products designed to be used in the green industry. Too many folks have children, grandchildren, dogs, cats, etc. Customers also prefer non smelling products.

We offered natural organic fert on a trial basis. Now we use clean products that work, don't smell, don't contaminate, and homeowners can walk on their lawn immediately (granular) or when it dries (liquid).

my 2 cents after 35 years

p.s. The day care centers who are customers also prefer non-organic because they have googled (after my recommendation)

greendoctor · Aug 21, 2013

americanlawn said:
Organic... a general term. Natural? Synthetic organic? How synthetic? Any more, most companies that sell "natural" organic fertilizer synthetically modify their products.

"Natural" organic fert can contain dangerous pathogens, contaminants and hazardous dust particles.

Manure runoff often causes many lakes & rivers "off limits" for swimmers.

We stopped offering "natural fertilizers" some years back because we were concerned about health issues. We prefer to use professional products designed to be used in the green industry. Too many folks have children, grandchildren, dogs, cats, etc. Customers also prefer non smelling products.

We offered natural organic fert on a trial basis. Now we use clean products that work, don't smell, don't contaminate, and homeowners can walk on their lawn immediately (granular) or when it dries (liquid).

my 2 cents after 35 years

p.s. The day care centers who are customers also prefer non-organic because they have googled (after my recommendation)

You know which "organic" I mean. A long time ago, I mentioned that making a client's property look or smell like a water treatment plant, stable or barnyard was not how I worked anyway. Only exception to that rule is kelp emulsion or the non pathogenic liquid biostimulants. BTW Milorganite is not legal in Hawaii. Too many heavy metals. C&C as well as many golf courses do spread sewage solids, then get the complaints.

It does not make economic sense for me either. I am not in the business of making compost. Any time I want to use it, I have to buy it. Get lots of broadleaf weeds free in that stuff as part of the bargain. On the other hand, I use clean liquid mixes that cost $5 or less per 1000. Reference that to the fact that any fertilizer starts at around $25 a bag, something containing coated urea is anywhere from $35-60 per bag.

Smallaxe · Aug 21, 2013

I've never heard of compost being carcinogenic...
another aspect being ignored in this discussion is building up the SOM, CEC, absorption/retention, microbes and soil structure in general...
Soil structure is very important to all plants and is a key environmental factor the determines the health and well-being of the turf... Synferts, add nothing to the structure of the soil...

foreplease · Aug 21, 2013

I agree with evry post here except Samallaxe's, which was way far off topic anyway.

Greendoctor, Milorganite fixed that problem here. They changed the label ha ha.

Some schools here have been bullied into using "organics." Turned out only about 1/4 of N was from organic source - and that was composted chicken manure. How would you like to get tackled face down in that? Many cases of chronic lung disease are attributable to poultry manure.

I get this question several times a year and I don't even work with homeowners. Usually it is to settle a disagreement between spouses. In Michigan we cannot use the word "safe" in any context with regard to pesticide applications but I have no hesitation in sending a team out to practice or play on a field that was fertilized yesterday or even the same day if they are not routinely tackling each other. In my view, the risk to the grass by letting them back on is greater than the risk to the kids.

Kiril · Aug 21, 2013

greendoctor said:
Chemical N, P and K is no more harmful than table salt. People do swim in the ocean, right?

Come now GD. One has to merely pull a couple of MSDS's to demonstrate this is not true.

andyslawncare · Aug 22, 2013

it isn't safe for kids to eat grass or leaves, and its bad parenting if they do that. Otherwise if you arent using other spray chemicals you should be ok. I tell my customers to wait until dry after a spray and the same thing is on the pesticide signs I even write the time and date and note liquid or dry of application on signs where I know they have dogs or kids. Placing a sign at the time of application takes it out of your responsibility. Its like slipping in a store with a sign stating 'wet floor' over the area of a wet floor.

greendoctor · Aug 22, 2013

Kiril said:
Come now GD. One has to merely pull a couple of MSDS's to demonstrate this is not true.

What is less likely to give someone E. coli, Listeria, Staphylococcus, Salmonella, or any number of parasites? Don't ever "come now" me. You hear? A child would have to eat fertilizer straight out of the bag or drink from the end of the spray hose to have a problem. DON"T EVER "come now" ME. I am talking about pathogens and parasites.

greendoctor · Aug 22, 2013

andyslawncare said:
it isn't safe for kids to eat grass or leaves, and its bad parenting if they do that. Otherwise if you arent using other spray chemicals you should be ok. I tell my customers to wait until dry after a spray and the same thing is on the pesticide signs I even write the time and date and note liquid or dry of application on signs where I know they have dogs or kids. Placing a sign at the time of application takes it out of your responsibility. Its like slipping in a store with a sign stating 'wet floor' over the area of a wet floor.

Don't know how other kids are raised, but I was told to stay away from recently sprayed areas when I was a kid. The fact that parents will not do that any more is the very reason why the EPA sees it fit to relabel most of the pesticides so they may not be used on lawns and landscapes. There is too much exposure to children contacting recently treated grass. Of course there are always some jackwagons who let their kids on a lawn with spots of blue marker, realize it is a pesticide, then call every state agency. Keep your kids off of sprayed areas!

wildstarblazer · Aug 22, 2013

So spreading compost is not completely safe either?

Smallaxe · Aug 22, 2013

americanlawn said:
Organic... a general term. Natural? Synthetic organic? How synthetic? Any more, most companies that sell "natural" organic fertilizer synthetically modify their products.

"Natural" organic fert can contain dangerous pathogens, contaminants and hazardous dust particles.

Manure runoff often causes many lakes & rivers "off limits" for swimmers.

We stopped offering "natural fertilizers" some years back because we were concerned about health issues. We prefer to use professional products designed to be used in the green industry. Too many folks have children, grandchildren, dogs, cats, etc. Customers also prefer non smelling products.

We offered natural organic fert on a trial basis. Now we use clean products that work, don't smell, don't contaminate, and homeowners can walk on their lawn immediately (granular) or when it dries (liquid).

my 2 cents after 35 years

p.s. The day care centers who are customers also prefer non-organic because they have googled (after my recommendation)

Manure runoff into lakes and stream should've ended years ago... Most runoff into lakes and streams come from storm sewers in urban areas...
The idea that natural fertilizers are a health hazard is a pretty wide stretch in the propaganda dept.,,, assuming of course. that one is not stirring up dust clouds with it and breathing it into their lungs...

Smallaxe · Aug 22, 2013

The e-coli, listeria etc. are found in food processing plants, raw manure straight from the animal, but never heard of it being in compost... anyone else???

Kiril · Aug 22, 2013

greendoctor said:
What is less likely to give someone E. coli, Listeria, Staphylococcus, Salmonella, or any number of parasites? Don't ever "come now" me. You hear? A child would have to eat fertilizer straight out of the bag or drink from the end of the spray hose to have a problem. DON"T EVER "come now" ME. I am talking about pathogens and parasites.

I won't ever "come now" you GD if you don't make ignorant statements like that which does nothing more than misleads your less informed peers and insults the more informed ones. You are better and more intelligent than that. And since we are in the reprimanding mood, don't you ever patronize ME, you hear?

But since you are talking about pathogens/parasites, what particular products specifically are you talking about? Compost, corn mean, bone meal, feather meal, etc ..... ? Or are you just talking about raw shiit? Should we also stop eating vegetables and meat as these can also carry these harmful organisms?

Here's a list of OMRI products for you. Please let us know which products we should avoid due to these harmful organisms.

http://www.omri.org/sites/default/files/opl_pdf/crops_alpha.pdf

As an example, perhaps the OP is concerned about his children picking up and eating the pretty blue fertilizer pellets he just put all over the lawn that look like candy? How many of those can they eat before becoming ill?

RAlmaroad · Aug 22, 2013

Kiril said:
I won't ever "come now" you GD if you don't make ignorant statements like that which does nothing more than misleads your less informed peers and insults the more informed ones. You are better and more intelligent than that. And since we are in the reprimanding mood, don't you ever patronize ME, you hear?

But since you are talking about pathogens/parasites, what particular products specifically are you talking about? Compost, corn mean, bone meal, feather meal, etc ..... ? Or are you just talking about raw shiit? Should we also stop eating vegetables and meat as these can also carry these harmful organisms?

Here's a list of OMRI products for you. Please let us know which products we should avoid due to these harmful organisms.

http://www.omri.org/sites/default/files/opl_pdf/crops_alpha.pdf

As an example, perhaps the OP is concerned about his children picking up and eating the pretty blue fertilizer pellets he just put all over the lawn that look like candy? How many of those can they eat before becoming ill?

Kiril:
Greendoctor has constantly given great help to many many members here. His advise is based on tried methods, proven rates, and many efforts with learned experts in turf. I very seldom seeing you giving nothing but, websites, hateful words or advise to people way across the country without regard for soil conditions, type or turf species. All of which enter into a decision. Re-read Greendoctor's comments. Oftentimes it seems that you are just trying to rack up the most posts of anyone. As a parent and teacher, no parent would allow their child at the age to wonder about much less out onto a lawn. You might! Or is that just another of your insights. I've never seen any pretty blue FERTILIZER much less it tasting like candy. Good Lord, get real and keep useless comments for yourself to mull over.

Kiril · Aug 22, 2013

RAlmaroad said:
Greendoctor has constantly given great help to many many members here.

Never said he didn't, did I? In fact, I think GD gives the most spot on advice of just about anyone who contributes to this website. That said, when he compares table salt and swimming in the ocean to synthetic fertilizers, stating it is no more hazardous than .... well he is wrong. You don't like me pointing it out .... tough. I'm sure he and you will get over it.

RAlmaroad said:
I've never seen any pretty blue FERTILIZER much less it tasting like candy. Good Lord, get real and keep useless comments for yourself to mull over.

Funny, cause I have a bag of pretty blue fertilizer sitting in my garage right now, and I never said it tasted like candy I said it looked like candy. But don't let that stop you from making statements about me you have no hope of ever substantiating and putting words in my mouth. :clapping:

phasthound · Aug 22, 2013

wildstarblazer said:
So spreading compost is not completely safe either?

Nothing is completely safe. Spreading properly finished compost will expose you to little risk of disease, but you might severely hurt your back. Spreading unfinished compost may expose you to pathogens.

Skipster · Aug 22, 2013

Kiril said:
Come now GD. One has to merely pull a couple of MSDS's to demonstrate this is not true.

I was intrigued by your proposed exercise, so I looked it up. According to Morton's Salt, common table salt (NaCl) has an LD50 acute oral toxicity to rats of 3,000 mg/kg. According to Agrium, 46-0-0 urea fertilizer (CO(NH2)2) has an LD50 acute oral toxicity to rats of 14,300 mg/kg.

As I'm sure you're aware, when an LD50 value is lower, it means that less of the material is needed to kill half of test population and is often used as a measure of toxicity.

A scan of the MSDS shows that common table salt is more toxic than urea fertilizer.

How Long To Wait After Fertilizer Application?

Nullqwerty

FdLLawnMan

greendoctor

phasthound

americanlawn

greendoctor

Smallaxe

foreplease

Kiril

andyslawncare

greendoctor

greendoctor

wildstarblazer

Smallaxe

Smallaxe

Kiril

RAlmaroad

Kiril

phasthound

Skipster

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