Is there any particular type or brand of fertilizer that I must avoid?

[PonyRiderMom]

Is there any particular type or brand of fertilizer that I need to avoid due to not being safe for / around horses, ever? I don’t think so, but I wanted some more opinions just to be sure.

Also, how long do you typically wait after fertilizing to turn the horses out on it? A week? Two weeks? A week but only if it rains?

I’m not super super in a hurry to turn them out on that pasture, BUT the sooner I can, the sooner I can fertilize where they are grazing now.

Also I have never fertilized grass, even when I lived in the suburbs – anything really obviously dumb that I need to avoid?

ETA: some relevant things:

1. I know I need to get the soil tested. I have had a million things to do to get this place ready for horses, and that has been de-prioritized.
2. We can assume the soil is acidic, given that I’m in the maritime PNW and looking at what is growing there now. I limed it late last summer.
3. I have not systematically applied manure, as I have no way to do this right now, but I have flung a lot of manure around out there.
4. I will be applying less than I think I need, to be on the safe side and avoid runoff. I live near the ocean.

[JB]

Get a soil sample analyzed, your county ag agency should be able to do that, even if you have to take them the sample (they should have sample bags, and instructions on how to do it) so you know what ratio and amounts of each of N, P, and K to use. Spring fertilization ratios and amounts are different from mid-Sumer is different from Fall.

If it’s a large enough acreage, a custom mix that someone else can spread is ideal, but smaller acres can use a bagged mix that’s close enough to what you need, and you DIY

As long as it’s straight fertilizer, in the ratio that best fits your need, it’s fine. No weed killer mixed in, just straight fertilizer

Apply as close to and before a soaking rain as possible. If it’s granular fertilizer and spread evenly, it’s fine to turn them out on it. Eating a granule here and there is fine you just don’t want big clumps they might chow down on. I’ve never kept the horses of the pasture, they live there full time. But, no clumps, and really close to a good soaking rain

[goodhors]

Have to disagree with JB on turning horses right out after spreading fertilizer. Especially if your choice for supplying Nitrogen is Urea in the fertilizer!

I soil test and spread the custom mixed minerals the soil test calls for, yearly. The Fertilizer Guy suggested Ammonium Sulfate as our Nitrogen source because we did not want Urea on the farm. It can cause laminitus problems to hooved animals of any species. You can look up Urea Poisoning to get more information about the issues it causes.

The Ammonium Sulfate is a more stable product, in that it does not vaporize into the air like Urea if predicted rain does not arrive within a day or so. It does not cause health issues in the long term either, with equines after grazing it. I try to wait a week or so after spreading, hoping a rain storm happens in that time, before letting anyone out to graze the fertilized fields. I walk the field hoping to see no granules of fertilizer still laying there. It just is not worth chancing the equines health by letting them graze over fertilizer too soon.

Depending on the quantity your soil test shows the land needing, you may want to break the large total into smaller applications, doing a spring, mid-summer, fall so the land can absorb it better. Huge application at once can mean fertilizer run-off into the water system. Wasted money there, plus very hard on the local ecology. Our newly purchased hay field was so bad in the soil test that Fertilizer Guy recommended multiple applications over the year to allow land to take up lesser fertilizer quantities it needed, to finally get the total amount on by fall. We used the same fertilizer mix on all three seasonal applications. Fertilizer Guy is the educated one in this area, we followed his suggestions on using the same mix in each season.

You probably can’t avoid Urea if you buy pre-mixed fertilizers. Read the labels for contents and proportions in the bags. Applying more of minerals than soil test calls for is wasted money again. They wash off, land does NOT save and store them up! Washed minerals cause havoc in lakes and rivers on downstream. I go to the local fertilizer supply, where they read my soil test, mix my fertilizer according to what it needs. I rent a spreader wagon that the tractor powers to get everything spread on the fields. It has worked really well for us. Hay field is now very productive, ratios are what is needed for growing good grass hay now.

Local area can have deficiency issues, which may or may not be helped with micro minerals in the fertilizer mix. Michigan here, no Selenium in my location, which can’t be helped with fertilizer. I seem to remember the PNW having a deficiency, Copper? Something to ask about.

[Pico_Banana]

I fertilized my two main fields last fall for the first time using granules (before I had the lawn guy do it and he used liquid). Can I tell you I watered and watered and watered and watered and I could still see granules on the surface. I didn’t feel comfortable turning them out until they dissolved more, so they moved into a third field for most of the winter (before they got moved to the dry lot when ice took everything over). I should go out and see what the fields look like now.

I’m anxiously waiting to see what the grass looks like with the fertilizer!

[goodhors]

Pico Banana Interesting on long granule dissolving time. Mine are usually pretty gone in short order. We do get heavy dews and I do try to spread right before a rain.

I tend to fertilize in the spring, since adding Nitrogen in fall is kind of wasted because the cold comes, short sunshine days, preventing grass growth. Spring application lets the Nitrogen get going to provide plant growth all summer. This is for both pastures and hayfields.

You might call and ask why the granules did not not dissolve quickly with whoever sold you the stuff. With that much water, it SEEMS like they should have been gone in short order! Maybe it was a bad batch and they should be informed. You may not want to buy from them again if dissolving so slowly is an issue with their product, so you tell them that!.

[Montanas_Girl]

@goodhors

I soil test and spread the custom mixed minerals the soil test calls for, yearly. The Fertilizer Guy suggested Ammonium Sulfate as our Nitrogen source because we did not want Urea on the farm. It can cause laminitus problems to hooved animals of any species. You can look up Urea Poisoning to get more information about the issues it causes.

I have corrected this misinformation here before. There is no link between urea fertilizers and laminitis (other than the risk of rapidly growing vegetative pastures in general for susceptible horses), and horses are LESS susceptible to urea toxicity than ruminant animals because they lack the ability to metabolize nonprotein nitrogen.