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Thursday - September 24, 2009

From: Greenport, NY
Region: Northeast
Topic: Herbs/Forbs
Title: How to use seaweed for mulch and fertilizer
Answered by: Nan Hampton


Dear Mr. Smarty Plants,I live on the Peconic Bay, Greenport, Long Island. We have an oyster farm and lots of seaweed. I've read that seaweed was used on farms in the past as mulch (fertilizer?). I would like to mulch my plants and trees with seaweed - what type of seaweed and what is the process? Thanks for the info.


Mr. Smarty Plants lives a little ways from the ocean so doesn't have direct access to seaweed, but he knows it does make an excellent fertilizer and mulch.  First of all, the Irish have been using seaweed for fertilizer for hundreds of years and also use it for food, making cosmetics and many other applications.  You can read about the history of seaweed uses in Ireland from the Irish Seaweed Centre.  You can make a liquid fertilizer from the seaweed to put on your plants or you can simply place the seaweed on the ground as a mulch around the plants. You can find numerous recipes for making your own liquid fertilizer on the internet—here is one from eHow.com and here is another.  In Seaweed Comes Ashore from Organa Horticultural there is a description of its use as mulch, fertilizer, and pest control and how it enhances growth in plants.  Ascophyllum nodosum (knotted wrack) is a common seaweed along the northeastern Atlantic coast and is likely the seaweed you have in your oyster farm.



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