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Best sources of N?

Posted by elisa_Z5 none (My Page) on
Wed, Feb 12, 14 at 9:38

I seem to be experiencing the low N conditions Pat talked about when no-till plus mulch method is used. Most of my plants thrive, but I have learned the meaning of the term "small potatoes" :) My potato yields last year were 6:1 rather than the 10:1 that Fedco says is expected.

I normally just pour some fish fertilizer into the potato planting holes, but now I'm looking at other sources of straight N (my soil tests high in P and K both) and I'm confused by the whole bat guano-soy meal-alfalfa meal-blood meal morass.

Suggestions?
Thanks.


Follow-Up Postings:

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RE: Best sources of N?

  • Posted by glib 5.5 (My Page) on
    Wed, Feb 12, 14 at 11:40

If you need straight N, and you have a large garden, a 50 lb bag of urea will keep you in business for a decade or so. You can always ask your husband to supplement it with his own.


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RE: Best sources of N?

  • Posted by digdirt 6b-7a North AR (My Page) on
    Wed, Feb 12, 14 at 12:31

Is your example of the potatoes the basis for assuming you need nitrogen? N is shoots and leaves related, not # of potatoes produced related. That comes from P and primarily K and micros. And Fedco's claim of 10 per plant is very high. IME 6 is a very good yield.

You say most of your plants thrive so that sure doesn't sound like N deficiency. Any idea what your soil pH is? That is a more likely issue IMO.

But if you think you really need N then as Glib said - urea works well. I prefer alfalfa meal as it is a slower release.

Dave


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RE: Best sources of N?

Yes, it's the potatoes, and Fedco's numbers, that made me think that my soil needs N.

Ph is 6.8 (started out 5.4, has been limed in years past) P and K, as well as Calcium and Magnesium are "Very High". Minerals such as boron, manganese, zinc, copper, iron and sulfur all in "range" according to the U of Mass soil test. OM is 8.5 %. Really, a great report card until I compare my potato yields to the Fedco catalog! The soil test suggested adding 1/4 lb. N per 100 sq. feet.

Interesting -- had thought that urea was not organic, but I see it depends on the source -- synthetic or not.

Maybe I'll just stop reading the Fedco catalog, and make sure I have enough rows of potatoes, and be happy with 6:1. :)


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RE: Best sources of N?

Six to one is not bad, IME. Sure, much higher is possible if all factors are close to optimal. Loamy moisture-holding soil, balanced and adequate NPK and traces, good potato weather, no CPB.....


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RE: Best sources of N?

This is no approved/certified organic urea...even if it comes from an organic source. It's kinda silly, but it's like that across the board because there's been almost no true organic urea available since the 1930s/40s and it's practically impossible to tell the "real stuff" from the "synthetic stuff" on analysis. It became insanely cheap to produce synthetically in the 1920s.

For bang-for-the-buck, blood meal and feather meal give good N for the price if you're looking to be strict about organic fertilization...unless you can luck into finding some true organic urea you can count on.

Btw, just because the bag says "organic urea" doesn't mean it's organic...and there's more than a few bagged sources that will stamp it on their bags...you gotta trust your source if it's important that it's truly organic.


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RE: Best sources of N?

Legumes in rotation, plus a clover cover crop if that isn't enough. Regards, Peter.


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RE: Best sources of N?

  • Posted by glib 5.5 (My Page) on
    Wed, Feb 12, 14 at 23:33

CRN is right, I had momentarily forgotten we are in the Organic group. But yes, they are indistinguishable.


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RE: Best sources of N?

Urea is not an acceptable form of Nitrogen for any organic grower. A recommendation of 1/4 pound of Nitrogen per 100 square feet is a pretty negligible amount and nothing to even think twice about,
What cultivar of potatoes are you growing? Are these new potatoes or an Idaho (Russet) cultivar? Maybe a fingerling type?
Your soil test results, and the other plants suggest it may well be the potato cultivar that is the reason for the small potatoes.


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RE: Best sources of N?

kimmsr -- they're not actually all small, mostly just low ratios. Definitely not fingerlings -- grew them once and thought they were a waste
. Last year I grew mostly Katahdin because they tend to be big, and I was hoping to up the yields. In past years it's been a slew of different kinds. Russet once, with poor yields. This year I'd like to go back to the favorites: Red Gold, Yukon Gold (I know, known for low yields), Carola, Green Mountain, and Katahdin.

When you say "don't think twice about" 1/4 lb of N / 100 feet, do you mean don't both with it?

Guess we'll stick with our free sources of urea :)


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RE: Best sources of N?

  • Posted by glib 5.5 (My Page) on
    Thu, Feb 13, 14 at 14:24

Those are organic!


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RE: Best sources of N?

Yup. Don't bother trying to apply such a small amount, An excess of Nitrogen in a garden where you are growing roots, like potatoes, will result in a lot of green growth and little of what you want, the tubers. Potatoes prefer a bit more Phosphorus and a bit lower pH then normal.


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RE: Best sources of N?

My soils are naturally high in phosphate; due to high leaching and sandiness both N and K certain to be low unless it has been added in some form recently.


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RE: Best sources of N?

FWIW, that soil test recommendation for N equates to appx. 109 lb/A N, hardly negligible for spuds especially if you avoid leaching the N through the season. I assume you had good vine growth, if you don't get good tops you'll never get good tuber production.

I used to use Alaska brand fish fertilizer back when I could afford it at $10/gal, it's more than double that now. The fish fert. is 5-1-1 and that N is ready for use for the plants. At 9.25 lb/gal, the Alaska fish fert. would provide 0.46 lb of actual N/gal so, it would cover you for 200 sq. ft.. If you're lucky, all the cats around you will smell the fish and come to add their own fertilizer, AAAAAAAHHHHHH!!!!

One of the most important things about N is managing it and your water because N can be readily moved out of the root zone (leached) never to return. The ability to move in the soil can be a plus with N, you can spoon feed it through the season with a drip system, or even when overhead watering with great caution, under certain conditions.


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