Marine harvest

When descends on the Atlantic
The gigantic
Storm-wind of the equinox,
Landward in his wrath he scourges
The toiling surges,
Laden with seaweed from the rocks:
Seaweed, Henry Wadsworth Longfellow

Exactly a year ago, I wrote about the kelp forests which lie offshore to the west of the Outer Hebrides and are part of the complex marine ecosystem of the shallow waters of the North Atlantic. After a winter storm large amounts of kelp and other marine algae are deposited on shores, providing food for wintering shorebirds and an invaluable supply of organic seaweed for the islands’ crofters and gardeners.

This winter has been particularly stormy with a succession of severe westerly gales throughout November, December and January. I had expected that large amounts of weed would be thrown up onto the beach, but still I was surprised by the sheer mass of tangle. At the northern end of our beach the piles of seaweed were over 2m deep and extended for 500m or more. So collecting seaweed was a job for a JCB and a convoy of tractors with large trailers.

The use of seaweed as organic fertiliser is a traditional practice but until recently it had fallen into decline as many crofters either do not have the time or equipment to enable them to make the most of this apparently ‘free’ fertiliser. The costs arise from the use of machinery and fuel for collection. However, with the rising costs of inorganic fertilisers and a demonstration of the effectiveness of seaweed on crop yields, the Machair Life+ project has encouraged a resurgence of this practice. With the end of the project insight it will be interesting to see whether the large-scale collection of seaweed which has been organised and funded by Machair Life+ will continue.

The kelp is dumped in large mountains on the edge of the machair and in April it will be spread over the cultivated strips using muck spreaders. The machair is held in common by the townships (crofting villages) and each croft has a number of strips and a souming (number and type of stock each croft can graze on a common grazings). The strips were originally allocated by lot to ensure an even distribution of good and poor land. These are cultivated on rotation: small oats and rye (for cattle feed) are grown for 2 years and then the land is left fallow for 2 years. The soil is thin and poor so the seaweed is a valuable source of organic matter and trace nutrients.

While the westerly gales persist the kelp will continue to accumulate on the beach, buts as soon as the wind changes and there is a northerly blow, it will all disappear. A testament to the power of the wind and waves. So the windows of opportunity are small and I’m expecting my ten tons of seaweed for the garden to be delivered any day now.

20 thoughts on “Marine harvest

  1. How amazing to have such a wonderful source of fertiliser delivered up by the waves. Ten tons of the stuff, lucky you.

    • The seaweed is one of nature’s gifts, but if its kelp you need a man and a tractor, it’s very hard work collecting it by hand in any quantity. With poor sandy soil and a large vegetable garden we need it in large quantities. It may sound a lot but it rots down to almost nothing!

  2. That’s an astonishing quantity, isn’t it? Certainly a shame not to use nature’s bounty – would it have been collected by whole families in the past, like harvest? You say your ten tons (what does 10 tons of seaweed look like, I wonder?) for the garden will be delivered any day – but you have share in the machair as well, do you? Is this where you allow the local farmer to graze his cattle that you told us about before?

    • I am always amazed at the quantity that gets washed-up and then disappears. Ten tons is about a large agricultural trailer full, similar to the one in the photograph. In return for a load of seaweed, an equivalent load of manure and a few favours, my neighbour grazes my fields and cuts the grass for silage/hay in the autumn. He also cultivates my machair strips but has strict instructions to use only seaweed and manure as fertiliser. I have 5 machair strips plus the three fields around the cottage and the coastal grassland around the house.

      • Thanks for clarifying that, Christine

        • Crofting land tenure and co-operative use is so complicated that I think you need crofting ancestry to understand all the technicalities. Of course times are changing and where one a croft was run by the entire family, now it tends to be run on a very part-time basis. It has always been subsistence agriculture and always will be, but it is integral to the islands culture, landscape and wildlife.

  3. Seaweed really is a great fertiliser isn’t it, and to have it on your doorstep is a bigger bonus. The storms have thrown a lot of stuff up this winter on my southerly beaches, my local beach isn’t a “collecting2 beach so very little normally ends up there – even so I still scavenge a few bags for the allotment

    • I’m naturally a great advocate of seaweed as a fertiliser, especially when combined with manure. It’s well worth scavenging a bag full here and there if you can, although one is supposed to have the permission of the land-owner.

  4. Ten tons sounds a lot! And a lot of spreading, but a huge benefit to the soil I am sure.

    • We like to let our seaweed rot for at least six months, so by this time it has become black and crumbly, a bit like garden compost. We spread it on the veg beds in the autumn and the winter with well rotted manure and by the spring it has virtually disappeared and we just turn the soil over, no digging required on light soil.
      It is a great soil conditioner, the plants like it and judging by the worm population explosion, so do the soil invertebrates.

  5. Is seaweed as good as they say for gardens? I’ve read about it but never had the chance to try it… mind you, spreading ten tons of seaweed over the garden sounds like a major undertaking!

    • I think so, especially if you’re growing fruit and vegetables. I use it with manure which adds some nitrogen or you can just add some organic pelleted manure for hungry plants like brassicas. It is a fantastic soil improver for both heavy and light soils, in four years I’ve gone from almost pure sand to something which resembles garden soil.
      Seaweed and muck spreading is one of the winter chores, but on a cold, sunny winter day it is a great work out. I normally limit myself to six barrow loads a day and the job gets done remarkably quickly.

  6. Ten tonnes?! Goodness, sounds like a lot of work to do soon!

    • I managed to get the fertiliser spreading done in the autumn before the bad weather set in, so there is just the fruit cages and the rhubarb to do, once it stops raining! The new delivery will sit and rot until next year.

  7. Fascinating! Would love to see more photo posts of the cleanup and composting at your gardens. Always loved to use a bed of seaweed in the bottom of the lobster steamer! Yum!
    Take care!

    • If it ever stops raining and blowing a hooley I’ll be out with the camera!

      • I know the feeling, as the wind does not stop much here this winter and much rain too. We even had one gale and I thought of you! 😉

        • Wet and windy is fairly typical winter weather, but this year it has been relentless. However, compared to what’s been happening in the SW of England we’ve escaped relatively lightly.

  8. Great article. I know nothing about seaweed, but is this the sort that you can cook with as well as fertilise the soil with, I wonder?

    • Kelp is definitely for the garden, although it is used by the pharmaceutical companies to produce alginates. Some of the seaweed that appears on the beach like dabberlocks and sugar kelp is edible and we can usually find carrageen and several kinds of dulse. I must admit I’ve never got round to trying any of these, perhaps I should.

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