Salt in Seaweed Mulch

[Grub]

There was a word or two on seaweed mulch here somewhere, but nothing that tells me whether I should rinse it or not.

The sacks of weed I collected aren't kelp but the dried ribbon-weed or seagrass you see in estuaries. It looks like perfect mulch but is quite salty.

My test batch that was rinsed and dried still tastes salty.

Is salt gonna be a problem in my beds in the long term? I want to use the seaweed or seagrass mulch under the usual sugarcane mulch I use to offer a few more trace elements during the season.

Thanks, Grub.

[Grub]

Sounds like I might have opened a can of worms.
Don't bother replying.

I'm rinsing regardless.

Don't ya love self-help?
Have a good day. - Grub.

[barkeater]

Sugarcane mulch? swEEEEEt!

And, re the seaweed salts, tomatoes, like asparagus, like a little salt. That is one reason Monmouth County, NJ, was the tomato and asparagus capital of the world in the 1800's. The sandy soil, called sassafras loam, still had salts in it from 1000's of years ago when it was part of the ocean floor.

Its proximity to NYC also helped give it the nickname, I guess. ;-)

[Grub]

And what is more I saw a tomato growing out of a crack by the Southport Yacht Club that looked healthy as a tomato can. I pickeda fruit and it was rock hard and tasted terrible. Obvosuly, a bird had dropped it after ingesting part of someone's lunch at the nearby outdoor dining area. So I'm betting you are right about salt tolerance in maters.

[Tomstrees]

ok Grub ( oh you'll get worms with seaweed mulch!) ~

I use it - love it - & promote seaweed -
It has so many micro-nutrients its not funny ...
your tomatoes will LOVE IT !

But yes the question arises often : SALT

I've done some research (not like crazy scientific stuff but alittle "googling" and article searching -

My results MAY vary because I live at the BAYSHORE.
Not the ocean side (maybe my seaweed has less salt)

When I first started collecting seaweed I would lightly wrinse some - and add it to my compost bin - and mulch with it ...

There is no "fish smell" and the "wet-grass" smell goes away as long as you don't stack it on too high - like an inch or two - it drys out quickly - and the results come rather quick ... usually in about 3 - 4 days your plants take off : in regards to fruit production & vegitative ~
I do not prune btw ...

However, after reading a number of articles, some started saying you didn't NEED to wash seaweed ; and salt was no problem ... so I just plain
stopped washing it ~ I added it all - mussel shells, sponges, sea-grass - everything ...
I would just collect bunches of the stuff ; lay it down as mulch and add to the compost bin ...

Its really been great for a free mulch and a nutritious soil builder ... I have clay soil (and you guys have seen my little mater patch) - my soils been superfied !!!

I would use your best judgement ... if you think its too salty ? Wash it ...
You know who is doing it in Australia that I've talked to about it ? Fullmoon - shes using "your" seaweed ~

We need her to chime in here ~

Tom

ps.
I also practice bonsai (my screen name, lol) - I know there can be issues with plants in pots with salt -
but I've had NO ISSUES in the ground ~

pss.
TYW would love some seaweed !!! lol ~

[landarc]

Grub,
If your really worried, just run it through the washing machine, a few batches at a time, take care of that garden salt issue in no time, I would think.

[Tomstrees]

here's a good informative read:

Using Fresh Seaweed
Seaweed is traditionally collected freshly washed up after winter high tides and storms and applied directly to the land. It is a highly valued, free resource, wonderful as a stabilising winter mulch. It slowly decomposes and is taken down by earthworms, conditioning the soil and supplying essential plant nutrients.

Seaweed as a fertiliser
It is the brown seaweeds that are most often washed-up on British beaches and used by farmers and gardeners. The two commonest types are the Laminarias (long, flat fronds) and the bladderwracks (Fucus species). A typical analysis of these shows nitrogen, phosphate and potassium levels roughly comparable to farmyard manure (slightly lower in phosphate) plus an impressive array of other minerals, trace elements, vitamins, amino acids, plant hormones and carbohydrates. Seaweed is a particularly rich source of trace elements, supplied in a form readily available to plants, and this makes it ideal as a natural fertiliser. At the same time, the carbohydrates contained in seaweed decompose very readily and act as a soil conditioner, improving soil structure and encouraging the proliferation of soil bacteria.

The advantages of using seaweed in the garden seem to go beyond the actual nutrients it adds to the soil. In this sense seaweed is the perfect organic fertiliser, working to improve the long term stability and life of the soil as a basis for healthy plant growth.

Collecting seaweed
Loose seaweed can be collected from the sea, or from the shore if it is newly washed up. In this state the salt levels are low and will cause no problems in the soil. Old weed, that has lain above the high water mark for some time, should not be used as it will be very high in salt. Living seaweed should never be removed from rocks.

As a mulch
Seaweed makes an excellent mulch because it is free of contamination from weed seeds and plant pests and diseases. Applied 10-15cm (4-6in) deep it gives effective short term weed control. It will gradually break down, adding valuable nutrients to the soil. Used in this way seaweed is particularly suitable for perennial crops and for no-dig systems. As a mulch on annual crops it can be dug in at the end of the season.

Dug into the soil
Seaweed is most often dug into the soil in the late autumn/winter, and weather and worms slowly break it down, preparing the soil for spring crops. It conditions the soil and acts as a slow release general fertiliser. In sandy soils, seaweed increases water holding capacity, and regular application to heavy clay soil can improve its workability.

Composting
Seaweed composts well when chopped and mixed with other ingredients in the heap. It works as a compost activator, stimulating bacterial activity. It is not a good idea to make a heap or stack purely out of seaweed as this may turn slimy and smelly.

An effect on plant resistance
A fascinating aspect of seaweed that still needs researching is its reported beneficial effect on plant resistance to pests, disease and other stresses, e.g. frost. Trials done on this have suggested that plants grown with seaweed, added to the soil or applied as a foliar spray, show increased resistance to red spider mite, aphids, eelworm, botrytis and other diseases and virus infections. The mechanism of this effect is not understood; it has been suggested that the plant hormone content and/or the high level of trace elements in seaweed are responsible.

Pollution
Sadly, our seas are polluted and seaweed absorbs its nutrients directly from the sea. It has been shown to accumulate both heavy metals and radioactive elements. It would, therefore, be unwise to collect and regularly use seaweed from coasts likely to be affected by radioactive or other industrial effluents.

~ Tom

ps. GO FOR IT !

[Tomstrees]

OK OK - LAST ONE I PROMISE ~ :wink:

We live near the ocean so SEAWEED is free for the taking and fairly accessible. Even so, it is not always on the beach. About the time when it would be really nice, the winds shift into the south and consequently the beaches are clean. Like so many other transitory resources, we have to arrange our schedule to accommodate its availability. When we take a walk on the beach we bring along woven polyester feed bags to fill and bring back to the garden. While it is certainly possible to make a special trip to gather it, why go out of your way, waste extra fuel and time, when with a little forethought the gathering can be fit into your routine? If we had a dump-bed truck just waiting in our driveway a special trip would be worthwhile, even so, we would still have to haul the seaweed to it in bags or barrels, range farther down the beach with each load, and at the other end haul it again in bags or barrels to the garden.

Fall is the ideal time to apply seaweed. It has all winter to break down and leach its minerals into the soil. It is most plentiful at that time. Seaweed has an enzyme in it that encourages germination. Our friend, Steve, once hauled truckloads of it to his farm and spread it out on soil loaded with pig weed and lambs quarters seeds only to discover the hard way what a wonderful germination booster it is. A heavy mulch is definitely recommended if you plan to add it to your garden.

Other properties of seaweed are:

it increased cold-tolerance for your crops
adds valuable trace minerals unavailable elsewhere
breaks down quickly (except for eel grass which is nigh on immortal)
There is little fiber in seaweed, so if you plan to compost it first, be certain to mix it with leaves or grass clippings if you wish to end up with more than a slimy mass (and not much of that).

One fall Ed covered a garden bed, in which he planned to plant parsnips, with a mulch of seaweed a full foot and a half thick. By spring it had rotted down to half a foot; he dug it in and planted in the usual manner and ended up with truly immense roots come harvest time. The best parsnips he ever grew.

One type of seaweed that makes a better mulch than a soil amendment is eel grass. we do not know why, but it is very slow to disintegrate. It is black when it dries, doesn't mat down much, sure looks nicer than black plastic.

Over the years the one concern we have heard most frequently is that people are, afraid that seaweed will make their soil barren because of the salt content. This has not been a problem for me, but if you do not want to take any chances or take our word for it, rinse it off first or leave it out in a rain storm before adding it to your garden.

As with any soil additive it is best to use a diversity of materials. If all you can get one year is seaweed and your soil is already rich in organics, then so be it. Next year go for the leaves to get the organic content back up. That resiliency is one of the best arguments for organic growing we can think of.


~ Tom

ps.
who is going to collect seaweed after work today ~

[Grub]

Thanks Tom.

I think I need some seaweed now. Nori, wakame, konbu... bring it on.

I'll take a pic of the seaweed I collected. It's more the seagrass not kelp. which my grandfather used, though it is also in abundance.

I went for the seagrass coz it'll be easier to work with as a mulch rather than dug in.

Cucumbers seem to be enjoying the first batch .

BTW: TYW is two days in the mix. News when it comes ot hand.

[Tomstrees]

collecting seaweed is fun -
but the results are amazing -
Here's to the start of your season ... Cheers ~

~ Tom

[michael johnson]

Tom hit the nail right on the head, when he said that seaweed increases cold tolerance to crops.

In certain mountain areas of the USA some seed savers organisation did some experiments a couple of years ago-using seaweed meal as a product trial, after some experimenting they found that soil and potting compost treated with it helped to protect tomato plants from 2 or 3 degrees of frost without any damage- whilst on the other hand untreated plants were wiped out totaly.

It also helps to stop young tomato plants turning blue with cold-the condition (blue) is caused by cold causing a calcium lock up in the main stem, and the trace elements in the seaweed keep the calcium flow going thus eliminating the condition.

The best seaweed possible to obtain in the dried and ground up to a meal product- is from kelp beds, as this seems to be slightly superior quality to other varieties, however some of the other seaweed species is also very good- especialy the bladder wrack type.

Everyone also knows that tomatoes when cut and sliced always taste that little bit more savoury and nice if they have a little salt sprinkled on them- it brings out the flavour.So slightly salty seaweed can only help in that direction

I often wonder if one were to grow Garlic very close to the tomato plant roots if it would impart a slightly garlicky flavour to the tomatoes, and if fed also with seaweed mulch would it produce the perfect Salsa flavoured tomato

[Tomstrees]

Mike -

Just so you know -
the first post was mine -
the others that followed
were articles ~
Don't want to take "their" credit ~

Tom

ps.
but did collect plenty seaweed last night !

[Full Moon]

Tom, I'll have to wait to report on the seaweed has this is the first year I experiment with it.
What I did was layer it with mushroom compost, horse manure, rotten straw in the new beds we built back in march/april. I didn't rinse it because it was going to "hopefully" get the winter rains to wash it a little. I left the beds exposed for the first 6 weeks or so and then covered them with black plastic. Turned everything a couple of times and it looks beautiful!
Did a test in the beds with green manure in July to see how it would grow and it went crazy. So I think we're good!
I've also put some in the compost bins to get them going.
Now let's just hope mother nature is kind to us this year we are already having WAY above normal temps and fires have already started. I think we're in for another very hot and dry summer.

[psa]

Originally Posted by michael johnson

I often wonder if one were to grow Garlic very close to the tomato plant roots if it would impart a slightly garlicky flavour to the tomatoes, and if fed also with seaweed mulch would it produce the perfect Salsa flavoured tomato

On that theory, you'd have sushi-flavored tomatoes, as the seaweed would impart their own special flavor besides the salt!

Seaweed is a macroalgea, and remarkably different from plantlife. It's carbon content is much lower and it is rich in many nutrients not found in such concentrations in terrestrial life.

[Tomstrees]

Full Moon -

Sounds like pay back for all of my
mouth watering mater pics
I posted during my season !!! :wink:

Just make sure there isn't TOO much nitrogen ...
then you get big plants ... no maters ~

I've been thinking more about this seaweed thing ...
My parents live 1 block from a lake ...
a lake with LOTS of seaweed ...
they've not been having great harvests ...
no washing needed ???
hmmmmm ...... what if .... oh boy, I got it !
to be continued !!!

~ Tom

ps.
have any of you near lakes given it
a try instead of buying seaweed fertilizer
or any ferlized ???