Well, we have a home a few doors in from the ocean in NJ, and the sea breeze is always damp. And my flowers are always amazing, with little help from me (unless you consider staying out of the way "help.") We are only down a couple of days a week, so the sea mist is the primary source of "watering."
I'll be interested in reading responses from those who are armed more with knowledge and facts than anecdotes.

bump

I did some poking around and this site seems to have a couple of pretty good middle of the road analyses of sea water and should serve well for "shoot from the hip" estimates:
Composition of Seawater

To figure out how much of anything you're applying in pounds or ounces, divide the parts per million ('ppm' which can also be expressed as 'mg/kg') by one million and then multiply that number by 8.35 to figure out how much of that analyte you will get with each gallon of water in pounds. Multiply that number by 16 to get ounces.
For example, sodium:

(10752 ppm of sodium / 1000000)*8.35 = .09 pounds (1.44 oz) of sodium per gallon of water.

Include chloride at 19345 ppm to find that the total amount of sodium chloride (NaCl) in that gallon of water is 4.02 oz. of table salt per gallon of water. That's important because in addition to their contribution to total salinity, both sodium and chloride are specifically toxic when taken up by plants. (Of course some of the sodium and some of the chloride will be parts of other salts but at the end of the day, the net effect is the same).

For comparison, that same gallon of water will give you 0.05 oz. of potassium and from the micronutrient category 0.00000067 oz. of zinc.

I can't tell you to do it or not but those are some tools to help you make your decision.

Thanks gargweb, that's a pretty impressive set of info.
I think I'll need to involve someone less phobic about numbers than me to help interpret: all those numerals and 'points' make me feel a bit nervous!

There's many a strange thing happens in science; many that we throw up our hands at, not believing, yet leavingthe door open for those in the know to educate us doubting Thomases.

Sea water...if we were ever caught marooned on a raft in the middle of the ocean, would we drink water that is all around us. How does that poem go.....water, water, everywhere; yet not a drop to drink.
Now we're being asked if a plant can do what a human cant.

We continually talk about how, during watering of our plants, salts are removed in the drainage water....and its bad business to leave the water in the saucer to be drawn back up....thus putting the harmful salts back into the soil and the roots.

I take that to mean, salts....any form of, are bad for the coninueing health of a plant.

Except the nutrients plants get from the air and water, those plants take up are salts. The problem with sea water is you have to take a very large dose of the bad salts to get a very small dose of the good. Any soluble in the soil solution that is unnecessary to the well-being of the plant, or is there in excess, contributes unnecessarily to the TDS/EC of the soil solution, which is a decided negative.

Ideally, you would find out what essential elements are deficient via a soil test and decide how to best supplement those elements. If no elements are deficient, it's not going to make your plants grow any better to add elements unnecessary, or essential elements in excess. Just as it wouldn't be wise to add a 10-52-10 fertilizer in an attempt to correct a K deficiency because of all the N and P baggage it carries, it makes no sense to similarly add so much baggage in sea water when it's certain the baggage outweighs the bennies.

Al

Well said, Al.

Al's explanation makes total sense, and I'll leave the seawater on the garden for now...
I'm still interested to hear of personal experiences, good or bad, including with seawater and pasture.
I need to find that farmer again!

Actually, I was referencing garden applications.

Using seawater to water plants or supply nutrients would be a little like, for those who buy precious metals for varying reasons, buying it in ore form instead of bullion.

Take good care.

Al

I have a related question: how much salt can a garden deal with without detrimental effects? I ask because my principal soil amendment is seaweed. I take care to collect it after a rainstorm and let it sit away from the garden a month or two, but still wonder just how close to disaster I'm playing it.
On the other hand, I read somewhere that even a class 1 hurricane dumps more than 500 lbs of salt/acre here on Cape Cod, and plants still survive. We all know humans cant drink 3.5% salt solution seawater, but we do just fine with 0.1% salt in athletic drinks.
So, how much salt per square foot can garden soil accommodate per year and leach out without undue effects on crops? Our annual rainfall here is in mid 40" range

Different plants have different tolerances for salt levels in the soil solution. Some plants are even able to take up salt water and exude the salt trough lenticels and leaf pores, where it is washed away by dew/mist/rain.

There is an 'ideal' level of salts (all nutrients plants take from the soil are salts) for each plant. That ideal level is when the level of salts/nutrients is high enough to prevent nutritional deficiencies but low enough that it doesn't impede uptake of water or the nutrients dissolved in water. We know that the process of osmosis depends on there being a higher level of solutes in the cell than in the soil solution. As the level of solutes in the soil solution reaches an equilibrium (isotonicity) with the level of solutes inside the cell, water and the solutes dissolved in it becomes unable to move into or out of cells. Just as curing salt pulls moisture from the cells of ham/bacon, a higher level of solutes in the soil solution can actually pull water from cells. Technically, this is referred to as 'plasmolysis', because the plasma membrane is pulled from cell walls as the cell collapses, but we most commonly refer to the condition as 'fertilizer burn'.

The thing is, these effects don't hinge on WHAT solutes are in the soil solution, only the total of solutes. If you were to add 3 tablespoons of sugar to your fertilizer solution, or baking soda, or Epsom salts, or table salt, any of the four would have roughly the same effect on the plants' ability to absorb water. From this, you can see that ANYTHING added to the soil solution that is not of benefit to the plant, is a detriment. One caveat I might make to qualify that last statement: Even though I can't think of one right now, there may be instances where some benefit may be seen where additions to the soil that increase the concentration of solutes but don't benefit the plant directly, can still benefit the plant indirectly because of a positive impact on soil quality. With this in mind, I feel pretty comfortable saying that with the garden taken as a community of plants, any amount of seawater is still not a good thing.

The only way I can envision it being a plus is if there was an essential element deficient in the soil solution that was needed in very minute quantities and was known to be contained in seawater in large quantity, such that a very small volume of seawater applied to the soil would be sufficient to eliminate the deficiency, AND the EC/TDS (solute level) of the soil solution was low enough and the other nutrients balanced (in a favorable ratio to each other) enough that the application of seawater wouldn't impede uptake of water and nutrients. There are enough 'ifs' and 'ands' in that observation for me to look to nutrient sources other than seawater.

Al

I gotta tel you Al, I'm learning more reading your explanations than I ever did listening to teachers!

Keep 'em coming and keep 'em simple.

If I had a way to give you a thumbs up symbol I'd throw one of them in too!

Thx

Lloyd

Easy way to know is to do 1 raised bed at a time. Start with one bed, water & keep records & photos. Then you can come back & be the Know-it-all with proof.
Other then that I am with Al.
josko, sea weed should be fine, it is more nutrient source then salt.

Many years ago, I read that seaweed was good for gardens, so my then hubby and I collected some seaweed. Came back to the house, dug holes for tomato plants bunged in some seaweed and then the little plants into the seaweed and soil. I then started to worry about the salt in the seaweed, however it was too late. The tomatoes grew extremely well and showed no detrimental affects from the seaweed. Why don't you give a couple of plants a try with your seawater, or better yet, give them some salty seaweed.

Dotty - I'm not being critical of your offering - only making some observations and doing a little general musing.

I think it's wise to realize that effects needn't necessarily be observable to be detrimental. If Lance Armstrong, or any other athlete, has an electrolytic imbalance or nutritional deficiency, you might judge him/her amazingly fit, based on appearance, yet their ability to perform to their greatest potential could be seriously diminished. We might be agog at the speed of a stock car doing hot laps, even though there was a slip-up and it was fueled with lower grade fuel than it was meant to compete with, but the difference might be readily observable with a stopwatch in hand or when the car and driver are engaged in a race.

I regularly run into growers who insist that the way they are growing produces perfectly healthy plants, when its factually more accurate for them to say "I'm happy enough with the way my plants are growing that I'm not interested in entertaining the notion that there is room for improvement"; or, "I'm not willing to allow that I might be able to improve on my practical applications".

Plants are no different than athletes in that there are a large number of limiting factors that manifest themselves only in the abstraction of lost potential. To offer an example, plants that are severely root bound often appear perfectly healthy to the unpracticed eye, even to the practiced eye in many cases. I offered comment on a thread at 'Houseplants' over the weekend on which another participant suggested we could leave plants in the same (container) soil for years and years with no ill effect. I commented because I/we KNOW that root-bound conditions seriously inhibit potential growth (which is measured in the increase in biomass), vitality, branch extension, and the plants ability to hold on to its foliage, not to mention it makes the plant more susceptible to insects and disease. If we have the knowledge, there is an enormity of conclusions we can draw regarding what will limit plants' ability to grow to their potential by applying what we know about their physiology and our understanding of other applicable branches of science, w/o having to go through trial and error, though that decision always rests with the individual.

There are many things that potentially limit growth and vitality. Our job, if we want our plants to grow as near to their genetic potential as possible, is to eliminate limiting effects, or reduce them to the greatest degree possible. It may seem fine to say 'why don't you try this or that' in the hope that it might work, but if you're unsure, you run the risk of lost potential that you may never realize you've lost. When it comes to plants, lost potential is very real, and it's a forever thing - it can never be regained.

That said, when we embark on these experiments that carry the potential for harm or lost potential, it IS good to test it on only a few plants grown under the same conditions as the guinea pigs so you can evaluate the results. Growers are not only notoriously poor observers, but what grower A might think are spectacular results, grower B might be ashamed of. From that observation alone, with no additional support, we can draw the conclusion that it's very easy to perpetuate less than ideal practices/habits without a basis for comparison or a reliable sounding board.

Al

Here is a link that might be useful: More about how growth is limited