# Fertilizing alfalfa before or after 1st cutting



## FarmerCline

Would it be best to fertilize an established stand of alfalfa now as it is starting to grow for the year or wait until after I make 1st cutting? With grass hay that I'm used to I always fertilize heavy now to get a large 1st cutting but since alfalfa doesn't need N I thought it might be different.


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## Vol

I give it a little jolt of Nitrogen(15pounds) on a pure stand starting out, but include with that a healthy dose of Potash....maybe even to the surplus side with K if my wallet can stand it. On average here, for every ton of Alfalfa you harvest, you are extracting 50 pounds of K.....amongst other nutrients.

Regards, Mike


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## IH 1586

This is just my 2 cents as I don't grow straight alfalfa. I would believe either or would be fine. If I was concerned I would take soil samples and then you could have a custom blended fertilizer made for exactly what you need. Around here it could also depend on whether you can get on the field in a timely manner without tearing up the field.

Of course if I am way off base I will learn something from everyone else.


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## Chessiedog

I wait till after first cutting . Alfalfa is a bit of a pig when it comes to potash meaning it will use up more then it needs . Most everyone around here that I know of waits till after the first cutting . I have also read best it you can spilt in half ,one after 1st cutting ,then after last .

Here's a link from Purdue if you wanna read what they say . https://www.extension.purdue.edu/extmedia/ay/ay-331-w.pdf


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## PaCustomBaler

Chessiedog said:


> I wait till after first cutting . Alfalfa is a bit of a pig when it comes to potash meaning it will use up more then it needs . Most everyone around here that I know of waits till after the first cutting . I have also read best it you can spilt in half ,one after 1st cutting ,then after last .


K luxury consumption, most all cool-season forages do it to the best of my knowledge.

Cline, I'd give it a shot of fertilizer in the spring before 1st cut and then another shot after 1st or 2nd cut. Like IH said, soil sampling is KEY! Make sure to get the additional test of sulfur and boron. Soil sampling in the spring is fine, but get it done quickly so you can have time for results to come back. As long as your pH is near-neutral, there should be no need for adding fertilizer N. You most likely won't see a beneficial ROI for the cost of N and the little bit of additional growth it gives.

P and K are biggies for alfalfa, as well as Sulfur. You'll roughly pull off 60 lbs of actual K and 40 lbs of actual P per acre per ton of alfalfa. I think off the top of my head, sulfur is around 25 lbs of actual S per acre per ton of alfalfa. Don't forget Boron as well. You only need 2 lbs of actual B per acre per year. If you don't apply Boron, you have the potential to cut your yield in half...it makes that big of a difference.

Good luck, feel free to fire away more questions


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## mlappin

Even our lighter ground can have seeps in the hillsides and quicksand pockets, we wait till after first cutting.

Also depending on what you're using, if you get a wet spring and can't make it all in time, that early application just helps it to get riper and ranker quicker.


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## endrow

Yep I agree with the before and after 1st cutting and then again in Mid September . We also grow very little straight any more most is alf/og mix


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## FarmerCline

Just getting a chance to reply.....been a busy day in the field planting and spraying. To give a little background on the field......was planted last spring and fertilized according to soil test at time of planting including 30 pounds of sulfur and 3 pounds of boron per acre. After last cutting in October I fertilized to put back what P and K I figured that I removed in the hay I made plus a little extra but no additional sulfur or boron. I know N it's not needed on established alfalfa but it gets some because I can buy DAP cheaper than super triple phosphate.

Considering I fertilized after last cutting I didn't know whether my 1st cutting yield would be reduced if I waited until after 1st cutting to fertilize. For orchard grass hay I always fertilize heavy this time of year to give it enough N for a real heavy 1st cut. Since alfalfa doesn't need N, fertilizing now might not give it that big boost in yield I'm used to in grass hay? This is my first year having an established stand of alfalfa.


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## swmnhay

I prefer to fertilize alf in the fall and then another shot after 1st cutting.Ground conditions are usually the best.And with fall application the plant takes nutrients into roots and makes the plant healthier for the winter.


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## PaCustomBaler

swmnhay said:


> I prefer to fertilize alf in the fall and then another shot after 1st cutting.Ground conditions are usually the best.And with fall application the plant takes nutrients into roots and makes the plant healthier for the winter.


Well said Cy, might help with less winter kill. Another plus with fall P and K fertilizering, those nutrients are relatively immobile in the soil compared to N...moving maybe 1/8"-1/4" per year without tillage incorporation. Gives a good head start compared to spring application.


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## mlappin

I do like swmnhay mentioned, we buy 6-15-40 by 25 ton lots for spring application on the row crop ground, after first cutting I spread the remainder on the hay ground, after last cutting I spread more potash with boron added.


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## endrow

FarmerCline said:


> Just getting a chance to reply.....been a busy day in the field planting and spraying. To give a little background on the field......was planted last spring and fertilized according to soil test at time of planting including 30 pounds of sulfur and 3 pounds of boron per acre. After last cutting in October I fertilized to put back what P and K I figured that I removed in the hay I made plus a little extra but no additional sulfur or boron. I know N it's not needed on established alfalfa but it gets some because I can buy DAP cheaper than super triple phosphate.
> Considering I fertilized after last cutting I didn't know whether my 1st cutting yield would be reduced if I waited until after 1st cutting to fertilize. For orchard grass hay I always fertilize heavy this time of year to give it enough N for a real heavy 1st cut. Since alfalfa doesn't need N, fertilizing now might not give it that big boost in yield I'm used to in grass hay? This is my first year having an established stand of alfalfa.


I would agree if you put ample P and K on in the fall I would not apply again prior to first . in pure alfalfa stands two applications per year would be plenty. we make more applications per year because we have mixed stands and like to give the orchard grass a little bit and nitrogen


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