“The use of seaweed or kelp as a fertilizer dates back many centuries. In 1681, a royal decree regulated the conditions under which seaweed could be collected on the coast of France. The kinds that might be collected and the manner in which they should be used were specified. Recently, however, seaweed has been recognized a much more than a mere ingredient of compost heaps. Research indicates that seaweed has a chelating ability, and that it improves cation exchange in garden soils and releases locked-up minerals.

“Seaweed has also been recognized for its ability to pass its high potash content on to potatoes, beets, cabbage and other plants that thrive on large amounts of potash. The potash content of seaweed is twice that of barnyard manure.

“Growth-producing hormones have also been discovered in ordinary seaweed. The growth stimulants gibberellin and auxin derived from seaweed are absorbed into the stomata of leaves, resulting in better plant growth and development.

“Recent findings show that high concentrations of seaweed keep seedlings from becoming leggy. Mixed in with garden soil, it will keep plants from growing too large and make them easier to transplant.

“Plants given seaweed show increased ability to withstand light frosts. Crop yields of tomatoes, sweet peppers and corn are increased as are the insect and disease resistances of these crops. The auxins in seaweed are even said to inhibit development of fusarium on tomatoes. Seaweed applications are also believed to control red spider mite infestation or orchard trees.

“Seaweed is also valued by gardeners because it is free from weed seeds, insect eggs and plant diseases.”
…continued next post

continued from previous post
“Types: Seaweeds used as fertilizers belong to two main groups found throughout the Northern Hemisphere. The first group consists of relatively small plants whose growth is unusually dense. They are called rockweeds and grow on the rock bottoms between high and low water. They are easily collected by pulling or cutting from the rocks. There are innumerable rockweed species, but knobbed wrack and bladder wrack are the most common. Both plants are distinguished by air-filled vesicles which enable them to reach the surface when the tide comes in, and thus receive more light for photosynthesis.

“The other group, sublittoral brown weeds known as laminaria, oarweeds or tangles, contains much larger plants which appear to have a root, a stem and a single large leaf. This similarity with land plants is very superficial for, in fact, these various parts do not function like their counterparts in land plants. Weed beds are often dense and growth is usually about 20 to 30 tons per acre. In May, the old growth is detached and cast onto the beaches and the plants develop a new front. The detached fronds decay rapidly and should be collected as soon as possible for composting.

“A third type, the giant kelp, grows off the coast of California. They are brown weeds and both annual and perennial types abound. Some of them exceed 200 feet in length. The shed their fronds between April and June and decay rapidly if the water temperature exceeds 76F(24.44C). Like other brown weeds, they are cast ashore during storms.

…continued next post…

…continued from previous posts…

“Composition: The chemical constitution of seaweeds is markedly different from that of the land plants. In general, land plants owe their rigidity to cellulose, whereas seaweeds contain only about 5 percent cellulose and owe their mechanical strength to alginic acid. The food reserve of land plants is starch; that of marine plants is laminarin. Mannitol takes the place of the sugars found in land plants. Alginic acid, laminarin and fucoidin are found only in seaweeds.

“The most interesting feature of seaweeds is their substantial amounts of many different trace elements. Barium, chromium, lead, lithium, nickel, rubidium, silver, strontium, tin and zinc have all been found in seaweed, along with traces of arsenic, boron, cobalt, molybdenum, and vanadium. The amount of these trace elements as well as the quantities of nitrogen, phosphorus and potassium varies widely from season to season. The chlorophyll content of seaweed is almost as high as that of alfalfa.

“Uses: Alginic acid, the primary component of the fronds, is very susceptible to bacterial attack. This property is undoubtedly the basis of seaweed’s activating energy in a compost heap. When only limited quantities are available, seaweed is best used as a compost accelerator. In two days, 200 pounds will heat to 100F (37.78C). When this is used as the core of a compost heap, the heap will be ready for use in six weeks. When only small quantities are available, the weed should be chopped and soaked overnight in hot water (one gallon to two pounds of weed). Pour this mixture over the compost heap. With dry, milled weed a temperature of 140F (60C) is sufficient, but fresh, chopped weed should be scalded and soaked initially at 160 to 180F (71.11 to 82.22C).

“A number of commercial seaweed extract concentrates are available.”

source: The Encyclopedia of Organic Gardening. New revised edition by the Staff of Organic Gardening ® magazine. Rodale Press, Emmaus, Pennsylvania, 1978. pages 999 – 1000

Normally I would just extract facts but the whole article was just so interesting. Hope this helps with your question in another thread.

When there as no supplier of seaweeed at all in my area I wrote to maxicrop and asked for a 25 litre drum of multiple concentrate.

It cost the horrendous sum of fifty bucks. This was in 1974. Twenty years later I was still using the same drum until the bottom rotted out of it and I had to make use of what was running out the bottom ie: finish the drum off.

I told people how magic the stuff was.. they told me I was a lunatic but they still wanted to know what I was doing to get the results I was getting on a frosty salt pan. They didn’t believe that seaweed could do all the things I said it could do. They thought I had some other magic such as marijuana juice or something. It took me a while to show that seaweed was what made my compost work so well.

One farmer who was more astute said; “seaweed seems to not act like a fertiliser. It doesn’t make things grow faster but instead seems to impart greater health as the plants either stop being sick or don’t get sick” .. I shook his hand.

Thanks for going to all that trouble Dinetta. i’ll read it all again in the morning when my brain is more receptive. LOL

Roughbarked I use maxicrop as well.

The old fellow that owned this place before us used to go and collect seaweed most weekends. Unfortunately by the time we bought he’d been way past gardening for a good many years and there were no beds left at all.

no beds left at all..
>

I took my son to see where his long dead granparents on my mother’s side had lived.. we caused a stir which I could write a whole thread about but that is a different story.. To concentrate .. The place was burned out in the bushfire of 1959 which destroyed much of the Southern Highlands/Blue Mountains area.. The two Pinus radiata that had been by the house and sheds repolpulated the burned area so that it was now an non endemic pine forest. No one had lived there or gardened ther since 1959. The year I took him there was 1992. I could still make out the garden beds and the fig and walnut tree were still alive.

One farmer who was more astute said; “seaweed seems to not act like a fertiliser. It doesn’t make things grow faster but instead seems to impart greater health as the plants either stop being sick or don’t get sick” .. I shook his hand.
+++++++

Yes, he expressed the conundrum rather well…

To think they realized the importance of seaweed back in 1681 by leglislation, and by 1979 RoughBarked could hardly procure the stuff…!

Thanks for going to all that trouble Dinetta.
+++

No trouble, Bubba..That’s a great book (I bought it in 1983)…when I want to work out how to apply the info to here (Australia) I just turn the book upside down!

(TIC)

;0

That was a good read Dinetta, thanks a lot. I won’t pretend I understood every word but it was really interesting.(I’m sure Bubba won’t mind others reading it lol)

orchid40 said:

That was a good read Dinetta, thanks a lot. I won’t pretend I understood every word but it was really interesting.(I’m sure Bubba won’t mind others reading it lol)

I might charge admitance. LOL

Bubba Louie said:

orchid40 said:

That was a good read Dinetta, thanks a lot. I won’t pretend I understood every word but it was really interesting.(I’m sure Bubba won’t mind others reading it lol)

I might charge admitance. LOL

:D :D

Dinetta said:

One farmer who was more astute said; “seaweed seems to not act like a fertiliser. It doesn’t make things grow faster but instead seems to impart greater health as the plants either stop being sick or don’t get sick” .. I shook his hand.
+++++++

Yes, he expressed the conundrum rather well…

To think they realized the importance of seaweed back in 1681 by leglislation, and by 1979 RoughBarked could hardly procure the stuff…!

I live quite a way from the sea .. or I’d be on the beach each morning collecting it.

I will account that seaweed does make things grow.. in that my toddling son managed to rock the drum and slosh some on the strawberry patch..I immediately hosed it down to spread the concentrate as quickly as I could fearing too rich a mix in on spot.. The result was strawberries that just leapt up and powered on like they were on steroids. So yes if you put enough seaweed on it can easily make fertilisers look silly.

interesting reading. a more southern orientation on seaweed is in Peter Bennett’s Organic Gardening book.

this is the crux of it isn’t it….the classification of a material as a “fertilizer” is based not by how much it will make the plants grow; instead it’s a clinical study of the NPK percentages. without trace elements, and complex catalytic reactions and symbiotic relationships we barely know about, a high NPK fertilizer can be next to useless. thankfully a “weed” of the sea contains plenty of those tiny things to make land plants grow so well.
when i’d grown a considerable number of herb cuttings and used dilute seaweed for most waterings, i had a high strike rate, and nice bushy roots.
generous foliar feeding of various lavenders…i ended up with lavenders 2 or 3 times their supposed max size. couldn’t keep up cutting it back. btw lavender cuttings also perform very well in compost….even though it seemed counterintuitive to me, as lavender is very sappy.
applied regularly to roses, it helps prevent/stop blackspot.
also makes plant cells tougher, and much less susceptible to aphid attack. so if i ever slightly overdo nitrogen and notice aphids on the increase, a watering with seasol solution knocks their population right back, without using a pest control agent.

regular over-application results in an oversupply of potash, and some vegies can suffer with boron and magnesium deficiency symptoms. for example, beetroot will stop growing, as it is sensitive to boron deficiency. i also now take it easy with seaweed on salad greens, as they can turn tough and flower prematurely. too much under the lemon tree can cause yellowing leaves from magnesium becoming unavailable.

overall, seaweed concentrate has many benefits, and will make a garden green up manyfold. over-use can cause some problems. it’s almost like magic but, the concentrate solution will do little to improve a poor soil, when applied as a soil drench. in good soil, microbial activity increases. as most things applied topically to soil, a generous watering beforehand is required; or the seasol applied to dry soil will not penetrate, and will be wasted.

salute to all the seaweeders out there.

I wish in many ways that I lived closer to a beach but seaweed collecting would be at the top of the list.

Using the bottles of seaweed found at the supermarket is not as good as getting your hands on the multiple concentrate.

Believe it or not I was using it on a saltpan in the middle of a rice farm and getting great results.

Yes mild seaweed solution is probably better than using rooting hormones as in many cases these just burn the bum off your cuttings.

Very good Aquarium, thanks for putting that up. Peter Bennett was the other influence, in fact reading his book after “reading” the Encyc, is what inspired me to develop an interest in organic gardening…

as most things applied topically to soil, a generous watering beforehand is required; or the seasol applied to dry soil will not penetrate, and will be wasted.
———-
Peter Bennett has carried out some experiments by the sound of it. i have never applied it to rosemary or lavender but it sounds like i should.
i’ve just watered – so seaweed on everything would be my next job.
thanks aqua.

ps – do i use it on aust. natives ???

the rumour is untrue.. Australian natives do like fertilisers.. and seaweed is one of those.. The rule of thumb however is to never over do it. A little .. applied more often is better than a lot applied in one go.

roughbarked said:

the rumour is untrue.. Australian natives do like fertilisers.. and seaweed is one of those.. The rule of thumb however is to never over do it. A little .. applied more often is better than a lot applied in one go.

ok – i am surprised at that – but i have just watered the natives so it might be an idea.

Some natives are not fond of applications of phosphorous designed to be used by non native plants.. However just simply redesign the mode and amount of phosphorous application and the natives won’t complain.

roughbarked said:

Some natives are not fond of applications of phosphorous designed to be used by non native plants.. However just simply redesign the mode and amount of phosphorous application and the natives won’t complain.

what does ‘redesign the mode’ mean? i only put a glug of seaweed solution in a 9 litre watering can. pretty dilute really.

yeah .. dilute dilute and dilute again.

the modus operandum of throwing great handfuls of superphosphate around is the one that needs redesigning.

Top thread this one, i’ve often wondered if ALL plants would benefit from seaweed solution. Time to buy one of them bottles with the hose adaptor and give the garden a good going over

Rook

I haven’t found a plant that dislikes being foliage sprayed with it. and i have never seen problems with citrus soil watering beneath considering that I mix all my soluble seaweed underneath my navel trees. They are the greenest trees with the sweetest fruit.

pepe said:

roughbarked said:

the rumour is untrue.. Australian natives do like fertilisers.. and seaweed is one of those.. The rule of thumb however is to never over do it. A little .. applied more often is better than a lot applied in one go.

ok – i am surprised at that – but i have just watered the natives so it might be an idea.

the reason that people say natives are a no no is because those with proteoid roots can’t tolerate phosphorus. However as roughbarked says otherwise they appreciate a little fertilising.

bump for Rook

bump
is this it?

Dinetta said:

bump for Rook

snap for dinetta lol.

pepe said:

bump
is this it?

snap! Pepe!

Dinetta said:

pepe said:

bump
is this it?

snap! Pepe!

Pepe and Dinetta, you are legends….thanks very much

I must print it out

Rook said:

Dinetta said:

pepe said:

bump
is this it?

snap! Pepe!

Pepe and Dinetta, you are legends….thanks very much

I must print it out

No worries Rook…great article from the Encyc, isn’t it? Turns your mind around a bit…