Seaweed for fertilizer? : LUSENET : Countryside : One Thread

Could you utilize fresh seaweed for fertilizer/compost? How would you reduce the salt content?

-- Lynne David (, February 26, 2001


We use kelp regularly in our garden. It helps to keep deer out of the orchard and garden and the other critters don't seem to like it much either.

I don't see why you couldn't use seaweed. I think what I'd do is rinse it in fresh water real good to remove the salt before applying it.

-- john leake (, February 26, 2001.

I'm not sure how concerned I would be about the salt content. When you get a soil test back, if you ask for micro-minerals, salt levels is one of the results. Fields can be salt deficient and it is not unusual for it to be spread on pastures in New Zealand. John Hill, can you help here?

-- Ken S. in WC TN (, February 26, 2001.

I am not an expert of seaweed types but I have seen 'bull kelp' used as fertilizer. Bull kelp is a very fleshy type of weed and is found washed up after storms. Some cattled like it as a special snack too.

Don't just drag up heaps of rotting, stinking, seaweed onto your garden! Drag a heap of it up past the high tide line and let it dry, then take it home and dig it right in. This was the advice the local garden centre gave me when we started to break in a hard clay residential plot here in Wellington.

I suspect that seaweed itself does not contain much salt and once the seawater is washed off most of the salt would be gone too. If your climate is like NZ it will get rained on a couple of times before it dries and that may be enough to reduce the salt.

There was a commercial product on the market in NZ for years, marketed by a reputable organisation but eventually proved to be almost ineffective. This was a concentrated extract of seaweed to be mixed with water and sprayed on pastures.

-- john hill (, February 26, 2001.

Sorry Ken, I should have read your post more carefully. I have never heard of salt being spread on pastures in NZ but that does not mean it is not common in some areas. Large areas of NZ are quite recent (1860 or so) volcanic ash fields which are notorious for being deficient in various minerals. I think NZ was one of the pioneers in the identification of the importance of trace elements in the wellbeing of livestock.

-- john hill (, February 26, 2001.

I saw a gardening program on PBS last fall that covered use of seaweed and plankton in use for composting last fall. Possibly you can access the information at their website.

-- Jay Blair in N. AL (, February 26, 2001.

I recall they used a lot of seaweed in gardens on the south end of Okinawa, when I was stationed there. Don't know if it was rinsed prior to use, or they just let it air-dry/rain wash, or etc. It seemed to help, though.

-- Action Dude (, February 26, 2001.

I get kelp at the beach. I fork it into buckets and I rinse it before adding it to the compost. Sometimes I just dig it directly it the garden. No chance of drying it first in our climate.

-- Laura (, February 26, 2001.

Hello Lynne, Scott and Helen Nearing, authors of "Living The Good Life" used seaweed for their gardens in Maine. If it was good enough for them then it is good enough for anyone. They started the movement torwards organic gardening (among other movements) in the early 1930's and continued organic gardening until their deaths in the 1980's He died when he was 100 years old and she died when she was about 90. Sincerely, Ernest

-- Ernest in the Ozarks (, February 26, 2001.

Kelp meal is dried and ground up kelp/seaweed from the area of Iceland. It includes: calcium, magnesium, nitrogen, phosphorus, potassium, sodium, sulfur, protein, ash, fat, colbalt, copper, iodine, iron, manganese, molybdenum, selenium and vitamins B2, B3 and C. Also includes: a complex of 17 amino acids, including lysine, hystide and proline; vitamins A, B1, B6 (Niacin), B12, D, E, K; carbohydrates; plant growth hormones - auxins, cytokinins and gibberellins. To my knowledge the only land plant to produce B12 is Comfrey.

Notice one of those listed is copper and sheep people say sheep should not be given salt blocks with copper, but I believe it is standard practice in some parts of Britian and Europe to allow sheep to forage for seaweed on the shore, or for it to be gathered and fed to them.

-- Ken S. in WC TN (, March 01, 2001.

We use rockweed for lobster bakes, then put the seaweed on either the compost heap or garden, depending upon the season and whether we have untilled space. Works beautifull for both, and the salt content is so low that it is not a problem. GL!

-- Brad (, March 01, 2001.

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