One more question. I think I read that seaweed could be used to fertilize bamboo. Would there be any preference for the type of seaweed? What would you have to do to the seaweed first, if anything? Would you compost the seaweed first? Anybody know?
Hi, I have used seaweed extensively on a wide range of plants. For several years it was my main fertilizer. Unfortunately now I do not have a good source. I think that the large brown seaweeds are easier to use. I would use fresh cut seaweed or material that has drifted onto the shore. Contrary to Michael I would not bother to wash or compost it but use it directly on the soil. If you wash it, you remove a lot of the micronutrients, especially the potassium. Although seaweed obviously has a reasonably high level of salt, it is less than in many commercial artificial fertilizers. If you do compost it, you need to add a lot of strawy material to give some body and an open structure to the heap, and you need to aerate the compost well by regular turning or you can end up with a smelly slimy mass. Seaweed is great stuff in the garden, you are lucky if you have a good supply. Good luck, BrianO
Thanks guys: The further north you go the less salt there is in the ocean. In the tropics the salt content is really high. Here it isn't so bad. I think I will try just leaving the seaweed spread out to get rained on a couple of times and go from there. An old timer here on the island used to put seaweed on his small garden, but I don't know if he gave it any pre-treatment first. He's passed on now, so I can't find out.
On TV I saw an account of some stony barren island(s) in UK where starting a long time ago people got the land suitable for crops by putting seaweed onto the rocks. Nowadays the oceans are so polluted that it seems there might be a problem with contaminants coming with seaweed, all the more so because it will tend to be coming from comparatively quiet waters near shore. However, there is also a problem with dangerous materials being included in manufactured fertilizers. Probably best to periodically sample soil of plots and have it tested for likely suspects. Agencies or businesses offering soil testing will probably have an idea what to look for. It's also a good idea to monitor nutrient levels of garden soils. Phosphorus in particular is often over-applied.
Well, yes, salinity does vary with ocean temperature and therefore with latitude. However the difference between 3.8% salt solution and a 3.3% salt solution is a moot point for most terrestrial plants. For seaweed though, it is apparently hard to add enough to significantly affect soil salinity, even if you fail to rinse it first.
On the Outer Hebrides, northwest Scotland. Mainly on sand, rather than rocks (look up machair). They still do; the Atlantic coasts are sufficiently free of pollution for this to be safe.
Many thanks: I think I will bring several different kinds of seaweed in and let them rinse off a bit. Do you think I should try to chop it up and let it decompose a little before I apply it? Or could I just go ahead and put some around the plants to let the nutrients go into the soil that way?
Recollection is dome-like near moonscape of hard-looking pale material, lumpy like bricks or loaves. Most unpromising in aspect.
Ron, the programme would have been referring to the Aran islands off the west coast of Ireland ( not UK !!). The rock is a hard carboniferous limestone which erodes into horizontal blocks separated by narrow clefts - it is called limestone pavement. The first job is to block the clefts with small stones (to stop the new soil washing away), then layers of sand and seaweed were added to build up the soil. Hard work! I have visited the islands many times and I do not think that anyone has made soil in this way in the last 50 years or so. Seaweed was a vital resource in these islands and all along the Irish and Scottish coasts. A major use was as a fertilizer. If you look at say the coast of Galway (mainland next to the Aran Islands) on Google Earth, you will see that almost all the settlement is within about 2km (say 1.5 miles) of the coast as this was the practical limit for carting the seaweed. The ready supply of seaweed fertilizer allowed continuous production of good crops of potatoes on small plots, allowing the population to increase rapidly in the early 19th Century. Then came the potato blight and there was no alternative crop to support such a high population and hence the Potato famine and mass emigration (often to Canada !). You could argue that if seaweed had not been such a good fertilizer, the population would not have grown so high in the coastal areas and so dependent on potatoes. In turn, the impact of the potato famine would have been way less. Ciao brianO
Yeah, that's right it was Aran Islands. The name caught my attention because I had read years ago about the gardens at Brodick Castle and seen photos of the Rhododendron sinogrande growing there.
Without seaweed, then, the population make-up of Canada as it is today may well have been different? And Nova Scotia may have been named differently?
Hi Ron and weekend gardner, Ron: Sorry - wrong island, wrong country!! The island with the Rhododendrons and Brodick Castle is Arran ( two rr's) off mainland Scotland. The seaweed-soil-rock island(s) are the Aran (one r ) islands off Ireland. the confusion is natural and common. I am sure that every year people end up going to the wrong one ! Aran is pure limestone and you will not see a single Rhododendron there. However, it is an extremely beautiful place with a wonderful summer display of limestone plants (some rare). In June it is like one fantastic rock garden - well worth a visit. Weekend gardner: Yes - it is an intriguing thought! Obviously though, there was a large population in Ireland away from the sea who used other manures and were also affected by the potato famine. But it is only along the coast that you see evidence of really high population densities with tiny fields that used to support whole families. The families also made a large part of any cash income from burning the kelp seaweeds to produce soda or iodine. Seaweed really was a vital resource and was jealously guarded. On the shore you can see old marker stones delimiting everyones seaweed patch. In some areas where seaweed was limited, stones were placed on sandy shores to encourage its growth and a simple form of seaweed farming carried out. Did any of these practices transfer to Canada ? ciao BrianO
We use composted manure in very early spring, however as they get bigger and bigger there comes much less need to bother with any feeding. I know when you're starting out you just want them to get big as quick as possible but they will reach a point where it really won't matter any more. :) I do know that seaweed contains a lot less salt than people think because we tried some as slug deterrent once and the slugs ate it like it was the most delicious thing they had ever come across. I haven't tried it for fertilizing though, manure is a lot easier to get here than seaweed.
This seaweed accumulates on the beach in NJ after storms. I've applied it as mulch to all of my plants with good results. Even the supposedly fastidious Acer palmatums ate it up. I agree with JCardina that once established they grow without much intervention. If you give them a lot of N they grow like crazy but won't stand so straight, in my experience. There is also the concern that seaweed gathered from the beach is loaded with biology that is lost when moved to the terrestrial domain. 2nd pic
Poetry to Burn: Interesting handle. Do you compost your seaweed in any way? Do you wait any time before using it, or do you just apply it right off the beach. I put a good load in a 5 gallon pail with fresh water 3 months ago. I suppose it should be good enough to use now. Thanks for the pix.
Cocobolo, I have done both. it didn't seem to matter. It makes good (stinky),tea too. You can definitely use what you've got in that pail. I go to the beach with 4-5, 30 gal contractor bags and walk around filling the 5gal bucket return to the car and dump it into the bags. In my small garden a few hundred pounds is just a dusting.
We are getting some healthy north-west winds right now, which blows right into our bay. There is quite an accumulation of seaweed so I think it might be a good idea to bring a few hundred pounds up to be composted. I can try putting some on to an unplanted part of the garden where the plants are due to go in next spring.
