Question
What about Salts?  Why are these bad esp if they have Potassium in them?
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The text above is a follow-up to ...

-----Question-----
We have a new sidewalk in front of our house.  I was told the previous sidewalk was damaged through the many years by toxic salts that corroded the cement.  It is snowing now and we need to figure out what else to use besides a shovel to get all of the snow and ice off the sidewalk.  Is there something that you would approve of for this problem?
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The most common ingredient in commercial Ice-Melter: Unrefined Rock Salt.  This product is 98 per cent Sodium Chloride.  If that sounds familiar, it's because you probably have some at every meal.  But instead you call it Table Salt.  And all Salt is bad for plants and sidewalks alike.

Which brings us to the subject of Artificial aka Chemical Fertilizers.  Yes, these are full of Salt - so much Salt you can melt ice and snow with it.

Calcium Chloride is sold as an icemelter.  It's famous for working faster than the other products.   Magnesium Chloride is packaged as Pro Melt Avalanche and other products.

But it's Potassium Chloride ("Safe Step" or "Zero Ice") that warms my heart.

It won't corrode sidewalks or decks.  And it won't kill plants and grasses.  Plus, it's made of Potassium - a component of the N-P-K ritual.  A salt still, but not such a dangerous one.  The least worst.

How's that for a full length novel?

Any questions?  

Answer
Potassium Chloride (KCl) is actually used as a Fertilizer.  This should tell you why I insist that the Intelligent Gardener does not use Chemical Fertilizers in the Garden.  It's a corrosive salt - "lease worst" as I said.  I use coarse sand and sawdust on my sidewalk, and a lot of shoveling.  Salt is murder on your lawn, your shrubs, and your soil structure.  Murder.

Since you asked, let's try to understand how a fertilizer could be BAD for you.

Potassium Chloride is made of Potassium and Chlorine.   These KCl crystals are the main use for Potassium Chloride in this country.  Potassium is the "K" in the "N-P-K" analysis on a bag of Fertilizer.

The "Chloride" part this formula is a serious problem for a fertilized plant.

Know why?

Salt.

Potential for burning roots and other plant tissue is a fertilizer's "Salt Index".  The online Texas Greenhouse Management Handbook (http://aggie-horticulture.tamu.edu/greenhouse/nursery/guides/ghhdbk/salts.html) points out that you inured roots with Salt: "This often predisposes the plant to a wide range of root diseases (i.e., phythium, fusarium, etc.).  Extreme injury may also interfere with water uptake and result in excessive wilting of the plant. It is extremely important to inspect the root systems of plants on a regular basis in order to monitor the effects of soluble salts."

Potassium Chloride has a Salt Index rating of 116.  That's one of the highest Salt Indexes of all commercial fertilizers.

Sure, plants need Potassium.  They use it for protein synthesis and other things.  The turf-website Earthworks (http://www.soilfirst.com/tnm_02_1998.htm) points out that plants need Potassium to "direct free nutrients (such as carbon, hydrogen and oxygen) out of the atmosphere and into the plant.  Without this activity photosynthesis would be severely restricted and the plant would struggle to make starches, sugars, proteins, vitamins, enzymes and cellulose."

So you can see why plants growing in Potassium-short soil are incredibly stressed.

But unless there is a low amount of Organic Matter, or the garden is very sandy, most soil has healthy amounts of Potassium.  A soil test is the best method to determine the need for Potassium, but most people should assume that if they are Intelligent Gardeners, this is not something they need to worry about adding to their garden.  Excessive K stresses plants, triggers Iron and Zinc deficiencies, and raises pH and Salt content to lethal levels.

And that's not the worst part!

There are few microbes in Ocean water.  You can't use it to water your garden, and you can't drink it.  Only extreme halophiles will survive there.  The Salt level is why.

But microbes thrive in fresh water rivers and lakes.  Would you fertilize those?

Yes, you're right: Potassium Chloride has a plenty of Potassium.  The Salt concentrations melt ice very effectively.  Of the few icemelters listed, this one is the kindest and gentlest on your lawn and sidewalk.  Still, it's bad.  If you have a choice, stick to shovels and sand.