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iron in soil

Posted by veggiecanner Id 04 (My Page) on
Fri, Nov 4, 05 at 0:20

On the Pepper Joes catalog there is a statement about spinich grown today has only a fraction of the iron on it as the spinich that was grown in the 50's.
How do I make sure my spinich has all the iron it should have for good nutrition.


Follow-Up Postings:

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RE: iron in soil

Well, first of all try and confirm that it really is true that the iron content of spinach has decreased dramtically. Ask "Pepper Joe" for his source for this information.

A lot of this belief lacks any confirmation (that I have seen) and is based upon rumor and speculation. I am not saying it isn't true, I am saying I would verify the source before accepting it as truth.

OK, so you want to grow spinach and ensure it gets plenty of iron. First, iron is a micro nutrient meaning plants don't need much, but they do need some. Very few soils are iron deficient so no supplimentation is necessary in most cases and if you are adding organic matter to your soil you have no need to worry about it.

Iron is bound to the soil in a form that plants cannot use if the ph is too alkaline. Do you know the ph of your soil? Most all veggies prefer soil that is slightly acidic to neutral and alkaline soils are trouble. Generally this problem manifests itself in iron chlorosis, but other forms of nutrient deficiencies also occur in alkaline soils too.

Another issue is too much phosphorus. This is one problem with using manufactured fertilizers, but it is also a problem with fertilizers labelled according to their NPK values regardless of origin. I do not know what soil type you have, but clay soils and soils with good organic matter are almost never deficient in phosphorus. It is a basic ion thing. Negatively charged ions are attracted to positively charged ions. Most plant nutrients are positively charged ions. Organic matter and clay particles are negatively charged which is why clay soils are usually fertile (the nutrients "stick" and is also why soils rich in organic matter retain nutrients better than soils lacking organic matter. A big exception is nitrogen in nitrate form which is negatively charged which is why nitrogen leeches from soil and becomes a pollution problem.

An excess of phosphorus prevents assimilation of iron and zinc. Unless a soil test reveals a lack of phosphorus, don't add any in the form of store bought fertilizers if maximum iron uptake is important to you.

Anyway, these facts have led some to conclude that the use of too much fertilizer over the years has resulted in crops which no longer contain the same nutritive value as they used to when soils were more 'balanced'.

Long story short is ask those who make the claims for their sources. If the plant looks healthy it is almost certainly getting enough iron.


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RE: iron in soil

Username, check with the Food and Drug Administration from where people are making the statements that most of the food we eat is lower in nutritional value today than even 50 years ago.


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RE: iron in soil

The FDA site is pretty big, kimmsr. Any chance you have a link?


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RE-: iron in soil

I looked at the FDA site and didn't find the info you are referring to. It may be there, but I couldn't find it.

I did find another site by googling. Not surprisingly it is a new agish health site, but even the information there, once one looks at their sources, is blaming the supposed nutritional decline on crop varieties rather than anything else. Long story short commercial agriculture cares about appearance, storage and shipping qualities and the like. There is no particular emphasis on nutritional content of the varieties so it has declined according to the article.

I really don't see how this would apply to a home gardener growing their own though. If the plant is healthy it will contain all the nutrients it is genetically supposed to.


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RE: iron in soil

Myself....over 50 guy....I try to not get too much iron. It can be bad for your health if you are older and male. Some people like my cousin got anemic from pain medicine that made him bleed.

Most vitamin/mineral supplements that are up to date don't put iron in their formulation. If a person needs iron [is anemic or nearly so], they can add it.


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RE: iron in soil

Also, most iron in "high iron" food sources are not readily absorbed from the digestive system. This is why a pill form of iron supplement is prescribed for anemic patients- it is generally more useful, better absorbed and used by the body, than the iron in dietary sources like spinach.


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RE: iron in soil

It's a popular belief in alternative medicine that soils are "depleted" and their mineral content is "used up". It's used to scaring people into buying vitamin and mineral supplements. At some time somebody compared some iron levels in modern spinach with to a particular set of published values from the 1920s (the original comparison was done in the 1970s which is where the "50 years" comes from). It's likely that the data from the 1920s wasn't very good -- comparing apples to oranges in effect. Anybody who does any gardening knows that if you "used up" all the iron in soil, your plants would stop growing and without mineral content there wouldn't be any soil there! A soil test will give you a good idea about the nutrient needs for your soil.


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RE: iron in soil

Over the last 10 years the mass media has had stories from the Food and Drug Administration about their tests that show foods are lower today in necessary nutrients than 25 yeas ago. That information should be somewhere on the USDA and FDA web site.


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RE: iron in soil

Fox news is a right wing, Christian, Republican dominated news channel that vehemently spews out racist christian "american" sentiment.
only watch it if you want to get conned by Rupert Murdoch and His War on Journalism...


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