Seasonal seaweed: harvest of the seasons, gift of the winds.

We recently went on one of our intermittent winter seaweed scavenges, in order to re-build our compost and manure piles ready for spring. Our supply of seaweed is important during spring for our potato beds; we cover them in winter (Nov/Dec) and leave the seaweed to rot down, then plant through any remaining, which then gets covered with compost or soil as we earth up the growing plants. It’s also important for our rhubarb and our asparagus beds, as well as valuable addition to our compost piles, and liquid fertiliser for our courgettes and pumpkins. We use seaweed in place of horse or cow manure to avoid the possibility of amino/clopyralid contamination and potential devastation for our allotment, something that has happened to many allotment holders on our site and across the city.

Winter along the south coast can be surprisingly stormy, and generally we’re assured of good supplies of seaweed during these months. Several days after stormy seas the seaweed harvest usually starts arriving on the shore. This year there’s been very little evidence of this. There are large seaweed beds off the coast at Bognor Regis, which provide the supply of Laminaria during the winter, one of the best seaweeds for mineral content. The Seaweed beds off Bognor are to the SW of Brighton, and the seaborne seaweed is moved along the coast through the process of longshore drift. The prevailing winds are from the SW, and the line of travel for longshore drift is also W-E. Hence, stormy seas tear seaweed from the seabed to the West of us, longshore drift transports the seaweed W-E along the coast then deposits it on the beaches, nearby. This year, the lack of seaweed suggests something else is happening.

Our current cold weather across the UK is caused by a weather system over the near continent. High pressure between Iceland and Norway has led to winds blowing East-West, from the high pressure to the north of us towards the low pressure to the west of the British Isles out in the Atlantic – remember ‘Winds blow from high to low’. So, I reckon, the winds have been blowing in the opposite direction to usual during winter, while longshore drift continues its movement West-East. This, I think has led to storm-torn seaweed clusters not moving inshore, but remaining suspended off-shore; the winds blowing from the East and longshore drift acting from the West has created an equilibrium. Hence, the distinct absence of seaweed this winter.

Such a small shift in our weather patterns, yet it could have a significant effect on our crops and harvests this year; I reckon we need to do some research.

collecting seaweed [2]

4 thoughts on “Seasonal seaweed: harvest of the seasons, gift of the winds.

  1. I can vouch for seaweed, although I always put it on the patio and give it a good rinse to help cut down on the natural sea salt. Also, it is imperative to cut it and leave some stem and the roots when harvesting, for obvious reasons. It will regrow in the sea if the roots and a bit of stem are put back in the sea. My late father had very heavy clay soil in London, and although it took about 8 months to rot down enough there, it made a vast difference to his beloved flowers. His neighbours didn’t much care for the initial smell, though, but then nor did the other passengers and bus driver as we brought it back in large carrier bags from a day outing to Worthing. I think we were lucky not to be told to get off and walk.

    • Thanks for your response, most welcome. A point on harvesting seaweed-you should never cut living seaweed from the rocks – this is illegal in the UK. What you can do. & it’s how we collect our ‘harvest of the sea’, is wait for windy or stormy weather. This will generally tear seaweed from the rocks, & you only have to wait a couple of days for the winds & tides to deposit it on the local beach.
      We’ll be posting on the difference seaweed had made to our crops this year.

  2. Thank you for your reply, Teresa. I didn’t know about not having cut from rocks so glad you said. I have only cut it from sand and pebbles, though. Thankfully I now live in beautiful Bognor Regis, so no longer have to hum out public transport to Wimbledon with seaweed. With a back garden of only about 20’X14′ and just beds in an even smaller front garden, I don’t need a great deal and don’t do it every year even. I do use a big black bin to make compost and just turn it out and fork it over before loading it back in every few weeks. I use an occasional bag of pet bedding straw from Wilkinsons to prevent it becoming too wet and sticky. Some wonderful compost has come out of that bin. The first load made plants grow like triffids! I look forward to reading how this year goes for you, which I do hope is very well despite the weather. We do so much need produce grown here instead of supermarket stuff that irradiated prior to import, with the small (if any) profit going abroad. Hope you keep on going.

    • I can only imagine your journey home via public transport with large bags of seaweed! I salute your tenacity.
      On cutting seaweed, we often find Laminaria, in particular, washed up after very stormy weather still attached to large chunks of rock & have to cut it off. We generally try & collect on a falling tide – it keeps your feet dry & means the seaweed is still wet& generally fresher. Does make for a wet car boot – lots of newspaper underneath helps & it all goes into the compost bin, anyway.
      We’re going to start writing again, but have been so busy planting & growing that blogposts have not been a priority.
      Meanwhile, hope you enjoy reading our existing posts.

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