The Benefits of Liquid Seaweed Fertilizer

One of the best fertilizers you can use on your plants is liquid seaweed, yet this is probably the last fertilizer people think of buying when they go to their local garden centre or shop online. liquid seaweed fertilizer is not only organic, but comes from a sustainable source and can be harvested without damaging the environment.

Most seaweed based fertilizers are made from Kelp, a variety of seaweed which can grow to lengths of over 50 metres.Trace elements found in seaweed organic fertilizers include magnesium, potassium, zinc, iron, and nitrogen -- all of which are beneficial to plants. Nitrogen, for instance, is essential to the production of nitrate, a key component needed by plants during photosynthesis.

In the Channel Islands, such seaweed fertiliser is known as vraicin their dialects of Norman, a word that has also entered Channel Island English, the activity of collecting vraic being termed vraicking. In Scotland, it is used as fertiliser in lazybeds or feannagan.

Falkland Islanders have also been nicknamed "Kelpers" from time to time, from collecting seaweed partly for this purpose.

Fermenting Seaweed
Fermenting Seaweed
Great for lawns or golf courses.
Great for lawns or golf courses.

One benefit of using a liquid seaweed fertilizer is that you can vary the concentrations according to what you are using the fertilizer for, so for instance, on a lawn you would probably use a more diluted mixture, but for a houseplant you would tend to use a stronger concentration. One thing I have noticed is that a little of this product goes a very long way with some pretty impressive results. Personally one of my favourite uses for liquid seaweed fertilizer is to give my exhibition vegetables a boost during the growing season in the hope I will stand a better chance of securing a few prizes once the Summer show comes around each August.

Foliar application is no doubt the most efficient and effective method of administering liquid seaweed to your plants . Kelp extracts are 8 to 20 times more effective when applied to the leaves then when broadcast on the soil. Spray as a fine mist until it drips off the plants’ surfaces and the plants will immediately absorb the fertilizer and begin to benefit from it by the second day.

Liquid seaweed fertilizer is used by many of the English and Scottish Football Premiership Grounds, as well as numerous UK Championship Golf Courses. In fact the high number of quality top sporting venues that use liquid seaweed extract as a fertilizer prove that it is extremely effective as a plant food.

Foliar Application

Pumpkin Growers Swear by liquid seaweed fertilizer.
Pumpkin Growers Swear by liquid seaweed fertilizer.

Advantages of Using Liquid Seaweed Fertilizer

1) It promotes additional buds when applied as the plants are beginning to bud.

2) It extends the shelf life of fruits and vegetables if applied 10 days before harvesting

3) It lengthens the life of cut flowers if they are sprayed with Liquid Seaweed a day or two before cutting.

4) Treating seeds or seed pieces with Liquid Seaweed prior to planting will improve seed germination, root growth, and early seedling vigor.

5) Liquid Seaweed also can be used as a rooting solution. Place cuttings in a solution of Liquid Seaweed and water until roots develop, then plant. When planting, water in with Liquid Seaweed solution.

6) Liquid Seaweed applied to pasture crops increases the nutrient uptake, the protein content, and overall quality of the crop.

7) Seaweed organic fertilizers can be used as a soil treatment to grow healthier, stronger, and more disease-resistant plants.

8) A wide range of beneficial effects have been reported from the use of liquid seaweed extracts including increased crop yields, resistance of plants to frost, increased uptake of inorganic constituents from the soil, more resistance to stress conditions and reductions in storage losses of fruit.

9) Promotes vigorous growth and helps deter pests and diseases on fruit, flowers, vegetables, lawns etc.

10) Seaweed has more than 70 minerals, vitamins, and enzymes.

11) Seaweed fertilizers are especially useful in organic gardening. They contain almost every micro-nutrient in a fully chelated (immediately available) form. They deliver a healthy dose of natural plant hormones. Seaweed is full of carbohydrates, which the plants use as a building block and which large populations of beneficial micro-organisms use as a food source.

12) Alginates, (sponge-like starches found in seaweed), hold water droplets near the plant roots, making moisture available to them without drowning them; they also help enrich the soil by feeding myriad beneficial microorganisms such as bacteria and tiny fungi necessary to composting.

13) Research at major universities has shown that seeds soaked in seaweed extract germinate more rapidly, have larger root mass, stronger plant growth and higher survival rate. Soaking plant roots in seaweed extract reduces transplant shock and speeds root growth.

14) Several university studies have shown that seaweed can produce dramatic results in plants: geraniums produced more flowers per plant; grapes were sweeter; gladiolus corms grew larger; and cucumber yields increased 40 percent and the fruits suffered less often from softening and rotting. Improved yields after seaweed treatments were measured in potatoes, sweet corn, peppers, tomatoes, apples, strawberries, okra, and oranges. Better frost tolerance, increased seed germination, and greater capacity to absorb trace elements were other documented benefits for plants.

15) Seaweed fertilizers have many benefits. They provide natural hormones and many nutrients not found in other forms of fertilizer. Since most plants absorb their nutrients through the leaves, applying this with a foliar method will benefit the plant even more. Foliar simply means placing the fertilizer on the leaf itself. As the plant absorbs the sunlight it needs, it will also be absorbing the nutrients found in the fertilizer.

16) Another major component in liquid seaweed fertilizers are the hormones. The main hormones in seaweed are auxins, gibbelerins, cytokinins and betaines. The roles of these hormones are essential to plant health. Most of these are only required in very small proportions. There are many different auxins and they all have their specific roles. Their main functions are the balanced control of speed of growth. They have both growth stimulating as well as delaying functions. They stimulate root-growth, prevent bud-forming or opening at the wrong times.

17) Seaweed can play an important role in the production of the plant's own auxins, because the enzymes formed with the help of trace elements from the liquid seaweed fertilizer play an important role in the formation of these auxins.

18) Cytokinins are another group of important plant hormones. They initiate and activate basic growth processes. The cytokinins available in liquid seaweed extract stimulate growth with greater vigour, because they mobilise nutrients in the leaves. They also provide protection from marginal frost (to -3 C). Cytokinins also retard the senescence (aging processes) in the plant.

19) Betaines play an essential role in the osmotic processes in plants. They help to increase the water uptake in plants and are extremely helpful in dry conditions. Betaines are particularly helpful to plants under stress.

20) Liquid seaweed fertilizers, (especially the alginates in the seaweed) act as soil conditioners. The alginates react with metals in the soil and form long and cross-linked polymers in the soil. These polymers improve the crumbing in the soil, and swell up when they get wet, and retain moisture for a long period.

Lawn Before and After.

How is Liquid Seaweed Fertilizer Made?

Liquid seaweed fertilizers are made from various species of seaweed, which are washed, dried, milled and processed to enable the natural benefits which the seaweed provides to act immediately upon coming into contact with either the plants foliage or the soil itself. This speeds up the natural processes by converting raw seaweed into an easily applied digested weed.

Harvesting methods ensure sustainability of the natural crop, and the selection of healthy weed growing under optimum conditions and season, guarantee the best growth promoting substance yield/activity in the liquid seaweed product.

Products are produced with no acid, caustic or organic solvents. Liquid seaweed fertilizer is a truly organic product that has been extensively used in organic grower trials.

Kelp Forest

 I can't rave enough about the benefits to using a liquid seaweed fertilizer on your garden, be it on your lawns, your flower beds, your vegetables or even on your houseplants. I personally have found the results incredibly impressive, and I love the fact this is a natural product which is harvested in a way that won't have any negative impact on the environment, or the sustainability of the seaweed itself. Those of you that have read my other articles on growing vegetables will know that I only grow my produce organically and I refuse point blank to spray any pesticides on my crops. The other advantage I have discovered is that the liquid seaweed fertilizer applied as a foliar feed actually seems to deter such nasty pests as greenfly and whitefly organically. What more could I ask for!

More by this Author

Comments 52 comments

diogenes profile image

diogenes 6 years ago from UK and Mexico

Excellent article, Miss Misty. I hope you got the idea from my seaweed hub. You always get such marvellous pictures! They make you want to be under the sea in some great, green cave with a mermaid. Seaweed has such a crisp, fresh look. Happy Christmas, dear. Bob x

Hello, hello, profile image

Hello, hello, 6 years ago from London, UK

Thank you very much for a great hub and advice. The tomatoes you show are special types of tomatoes or can you grow 'Alicante' like that?

Now, diogenes, will you leave those mermaids alone. tut tut tut ha ha ha

Tatjana-Mihaela profile image

Tatjana-Mihaela 6 years ago from Zadar, CROATIA

Excellent Cindy...and so green....

hypnodude profile image

hypnodude 6 years ago from Italy

Very interesting. These days I use water from my fish-tank as a fertilizer, but I didn't know about using seaweed. This is very interesting. Thanks for this. Your hubs are great.

Martin Guernsey 6 years ago

Hey Misty Horizon.

This is a brilliant article. Thank you for the terrific information. I'm sure that I can use it for great benefit.

I really appreciate it.

steph 6 years ago

lovely article love info on green

mistyhorizon2003 profile image

mistyhorizon2003 6 years ago from Guernsey (Channel Islands) Author

Hi Bob, thanks so much for the great feedback and compliments. I love the pictures under the ocean as it feels like entering another world.

Hi Hello Hello, I know there are varieties of tomato purely meant to be grown in hanging baskets due to their "tumbling habit", but I imagine Alicante could work well too if you gave them a try. Certainly seaweed fertilizer will benefit any type of tomato plant.

mistyhorizon2003 profile image

mistyhorizon2003 6 years ago from Guernsey (Channel Islands) Author

Hi Tatjana, the fact it is so "green" is one of the things I love about it. Thanks for the feedback.

Hi Hypnodude, that is a good idea for use of your fish tank water. Thanks for the compliments too. :)

Thanks Martin, glad it was helpful to you and hope you give it a try :)

Hi Steph, thanks for commenting. I am all for anything green too :)

kartika damon profile image

kartika damon 6 years ago from Fairfield, Iowa

Very informative! I will try this out this spring and pass this on to my friends who garden! I love green and this is new to me!

mistyhorizon2003 profile image

mistyhorizon2003 6 years ago from Guernsey (Channel Islands) Author

Hi Kartika, please do give it a try as I am certain you will be delighted at the results :

Paradise7 profile image

Paradise7 6 years ago from Upstate New York

Very interesting, informative and well-written hub. I liked the pics, too, and am with you all the way in your organic gardening efforts. The contrast between the two lawns was especially amazing. Fine hub, friend!

mistyhorizon2003 profile image

mistyhorizon2003 6 years ago from Guernsey (Channel Islands) Author

Thanks Paradise, organic is always best if you ask me. Nature provides what we need if we just make the effort to utilise it.

Tanmaye Seth 6 years ago

How much does this seaweed ferteliser cost, and so far the best results have been seen on which plant/crop/field etc. ?

What is the cost-benefit working?

mistyhorizon2003 profile image

mistyhorizon2003 6 years ago from Guernsey (Channel Islands) Author

The variety I use costs £5.99 a bottle plus £2.50 postage to UK destinations. This bottle dilutes down on a basis of 10ml (2 x teaspoons) to 6 litres of water. The bottle contains 500ml (half a litre). This means one bottle will make 300 litres of the mixture. This rate applies for normal watering of plants. If you are using it as a foliar spray you can double the dilution rate therefore getting 600 litres per bottle.

I can't answer which crops have shown the 'most' benefit from using it, as the results seem to be across the board, i.e. lawns, houseplants, fruits, vegetables etc. I would suggest using it on anything you grow.

As to the last question, I would say this is a very cost effective treatment for plant feed as a little goes such a long way. I use mine on houseplants and vegetables, the latter of which I enter in local annual shows. The seaweed ensures, healthier, larger and tastier crops all round.

GusTheRedneck profile image

GusTheRedneck 6 years ago from USA

Misty - A very interesting and useful article, this one. I have also been reading some articles about the use of diluted sea water and of reconstituted dried seabed minerals as plant food, particularly in hydroponic settings. Whenever the Gulf of Mexico clears of the crude oil being leaked into it, it is my hope to capture about ten or 20 gallons of sea water with which to play around. thanks for the interesting article.

Gus :-)))

mistyhorizon2003 profile image

mistyhorizon2003 6 years ago from Guernsey (Channel Islands) Author

Cheers Gus, not sure about using seawater as I would have thought the salt content would have killled the plants, but let me know if it works or not when you get a chance to try it.

Mini Greenhouse 5 years ago

Ive heard about seaweed fertiliser before but never really took much notice about it. This is a really interesting hub and I think i'll give it a go now and see for myself. Thanks!

mistyhorizon2003 profile image

mistyhorizon2003 5 years ago from Guernsey (Channel Islands) Author

You are welcome Mini Greenhouse, the stuff is fantastic and very sustainable too.

Bibbles 5 years ago


mistyhorizon2003 profile image

mistyhorizon2003 5 years ago from Guernsey (Channel Islands) Author

Hello Husband, a man of few words ;)

vikinghex 5 years ago

i found this most enlighting and very helpful i now use seaweed liquid feed instead of any other. my results are all ready very good thanks.

mistyhorizon2003 profile image

mistyhorizon2003 5 years ago from Guernsey (Channel Islands) Author

Thanks you vikinghex, it is great stuff and am glad you are finding this out for yourself.

mistyhorizon2003 profile image

mistyhorizon2003 5 years ago from Guernsey (Channel Islands) Author

Please stop Spamming these comments jmscooper04, as you see I have deleted both of your recent ones, and will continue to do so if you continue to post here with comments stacked with your own personal links.

Stephen Harris 5 years ago

I have found this article very useful research with some of the work I am undertaking at University. The topic I have got is all about growth in grass(s) but the inclusion of seaweed would appear to also help its growth...

mistyhorizon2003 profile image

mistyhorizon2003 5 years ago from Guernsey (Channel Islands) Author

Glad it helped you out Stephen, and thanks for commenting :)

farida 4 years ago

this article very useful research

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

Thank you farida, really pleased you found this useful :)

Kris Heeter profile image

Kris Heeter 4 years ago from Indiana

Very interesting and useful article. I've not seen this around here but I'll bet some of the specialty garden supplies stores carry it. Liquid worm casting and dry casting fertilizers are pretty popular around here for organic gardeners. Great hub!

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

Hi Kris, I am surprised you have not seen it around as most garden centres stock concentrated liquid seaweed feeds, but then maybe you weren't looking for it before. The easiest thing to do is to order it off the net, Ebay or Amazon have a good range, and the Oceanic one I link to in the article is very good (I use it myself). Hope you manage to try some out. Thanks for the good feedback too :)

Victoria 4 years ago

My patch of garden is a foot of top soil and clay, would my garden benefit liquid seaweed feeds? When i bought my unit i did not check the depth of the soil. I was told to get some gypsum and put it through soil, but being on my own find it to much hard work. Look forward to hear from you Kris :(

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

Liquid seaweed or real seaweed will benefit the plants that grow in that soil. The problem is that if you want to improve the soil consistency, type and texture, you need to add organic matter as opposed to a liquid that will drain away without any plants to feed off of it. If you want to improve the soil itself I recommend adding as much organic matter as you can, e.g. actual seaweed, spent compost, lawn mowings, home made household compost, well rotted cow manure or horse manure, well rotted leaf mould etc. You don't have to dig it in, just smother the surface of the soil with a thick layer of the stuff and then let the worms and the rotting process mix it in for you. I have written on this subject elsewhere. If you want to read about it you can read my article at the following link:

scamver 4 years ago

Is the eucheuma spinosum (eucheuma denticolatum) can be use as fertilizer for eggplant?

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

I have never grown eggplant scamver, but I don't see why not. Most seaweeds can be used as compost or fertilizer, but the easiest way is to buy the liquid form as opposed to having to collect your own from the beach, not least because in some areas it illegal to remove it from beaches, plus it reduces hugely in size as it dries out so you need a lot of it.

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

Thanks for your comment DiggyBob, unfortunately I could not allow it based on the links it contained which qualify it as SPAM. If you wish to comment without the links I will be able to allow them.

Thanks again.

desert gardener 4 years ago

I tried fish emulsion but detest the smell. Does seaweed fertilizer have a fishy odor?

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

I didn't find it had any smell at all, and as it is a very watery liquid it drains down immediately to the roots. You would get a smell if you used real seaweed (I have done this too), but even that stops after about 2 days as the surface dries to form a layer between the air and the moist seaweed below.

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

That is great doctor, but you don't buy it from me, you need to click on the appropriate advert in this hub in order to choose to buy the relevant product. I know the oceanic team are now looking at offering to sell in bulk as well as smaller quantities if you email them.

doctor 4 years ago

thanks you mistyhorizon and what hub address?

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

Hi doctor, no it isn't a hub address at all. If you want to enquire about the Oceanic liquid seaweed fertiliser you need to go to their website and enquire through the email link there. The website url is :

doctor 4 years ago

very very thanks,you very friend good days:)

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

You are welcome. Good Luck :)

Richard Wenham 4 years ago

Is it OK to treat grapes With liquid kelp after the fruit has set?

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

To be honest Richard I would probably recommend this, mainly because with most fruits e.g. tomatoes, it is most important to feed once the fruit has set, and I am sure grapes will be no different.

tony 4 years ago

i have used it for years it is a great pestaside organic ovcourse

mistyhorizon2003 profile image

mistyhorizon2003 4 years ago from Guernsey (Channel Islands) Author

Hi Tony, well as a 'pesticide' I can't say I recommend it as it wouldn't work. As a food for your plants it will (of course.)

jackinabox profile image

jackinabox 3 years ago

Great article. Very useful.

mistyhorizon2003 profile image

mistyhorizon2003 3 years ago from Guernsey (Channel Islands) Author

Thank you jackinabox, I love the stuff and can't recommend it highly enough :)

pallmall 2 years ago

would like to try this on tomatoes in a high tunnel

mistyhorizon2003 profile image

mistyhorizon2003 2 years ago from Guernsey (Channel Islands) Author

Good idea, tomatoes love liquid seaweed which is why it is often incorporated into commercial tomato feeds such as 'Tomorite'.

Canadian guy 21 months ago

Seaweed Fertilizer

mistyhorizon2003 profile image

mistyhorizon2003 21 months ago from Guernsey (Channel Islands) Author

Here in Britain it is actually spelled fertiliser not fertilizer if that is what you meant in your comment Canadian guy.

MCDeed 18 months ago from Melbourne Australia

Misty, great article I have always praised liquid seaweed as a great foliar spray and soil conditioner. Thanx for all the info in one place. I just used it on my chilli plants as they looked a little hungry for nitrogen and other goodies after setting pods all season. Just came to research if I needed extra nitrogen or if seaweed would do the trick. I think I will wait a day or two and see. Cheers again

    Sign in or sign up and post using a HubPages Network account.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.

    Click to Rate This Article