PDF download Download Article
Incorporate seaweed in your garden by using it as mulch, fertilizer, or compost
PDF download Download Article

Seaweed is a great natural fertiliser that all your plants will love. It can be used as mulch or as a fertiliser. The great thing about seaweed is that is full of trace elements that are often not found in other common fertilizers such as manure. Seaweed also increases water retention in sandy soils and build up disease resistance in the soil.

  1. Be sure to check with your council or local government first for in some areas it is illegal to take seaweed off the beach. [1]
    • Kelp is generally the best option, but other types of seaweed work great as well. Collect the seaweed in a plastic bag and if the seaweed is not already wet, be sure to wet it with some seawater to prevent it drying out.
  2. However, if you have extremely acidic soil you could use this to your advantage and not wash off the sand. [2]
    Advertisement
  3. You could make it into a liquid fertiliser, add it to your compost or use it in its raw state in the garden.
  4. If you don't, the seaweed could become slimy and suffocate the compost.
  5. All you have to do here is add a little bit of water and wait for the seaweed to decompose.( This usually takes a few months.) Liquid seaweed solution can be used on all parts of the garden. It's particular effective in helping plants bearing fruits or flowers for the seaweed builds up disease resistance. [3]
  6. The common mistake that many people make is mixing it into the soil. You should never do this for, as the seaweed breaks down, it will rob the soil of nitrogen. The correct way to apply seaweed is on top of the soil. Gradually over time worms and other soil creatures will bring it down into the soil. The results from this method are marvellous for there is a slow release of trace elements into the soil. [4]
  7. Advertisement

Expert Q&A

Search
Add New Question
  • Question
    What are the ingredients and characteristics that someone should be looking for in their fertilizer?
    Ben Barkan
    Garden & Landscape Designer
    Ben Barkan is a Garden and Landscape Designer and the Owner and Founder of HomeHarvest LLC, an edible landscapes and construction business based in Boston, Massachusetts. Ben has over 12 years of experience working with organic gardening and specializes in designing and building beautiful landscapes with custom construction and creative plant integration. He is a Certified Permaculture Designer, Licensed Construction Supervisor in Massachusetts, and a Licensed Home Improvement Contractor. He holds an associates degree in Sustainable Agriculture from the University of Massachusetts, Amherst.
    Garden & Landscape Designer
    Expert Answer
    It depends on what you're growing. If you want to grow organically, you will add quality compost and a little bit of nitrogen fertilizer. You don't need to add other things. If you're looking for a fertilizer that does everything, you want a balanced fertilizer. If you look at the front of the bag of fertilizer, there are three letters, NPK, representing nitrogen, phosphorus, and potassium, along with their quantities, for example, 10-10-10 or 20-20-20. This is much more potent and a lot easier to over-apply. You have to be very careful. An organic fertilizer might look like 3-3-3 or 3-5-2. It's generally weaker and you have to generally apply more of it. What you apply is based on the requirements of your plants. Some plants want more fertilizer than others.
  • Question
    What's the difference between certified organic and conventional fertilizer?
    Ben Barkan
    Garden & Landscape Designer
    Ben Barkan is a Garden and Landscape Designer and the Owner and Founder of HomeHarvest LLC, an edible landscapes and construction business based in Boston, Massachusetts. Ben has over 12 years of experience working with organic gardening and specializes in designing and building beautiful landscapes with custom construction and creative plant integration. He is a Certified Permaculture Designer, Licensed Construction Supervisor in Massachusetts, and a Licensed Home Improvement Contractor. He holds an associates degree in Sustainable Agriculture from the University of Massachusetts, Amherst.
    Garden & Landscape Designer
    Expert Answer
    Basically, there are restrictions on the types of chemicals, the types of insecticides, and the types of fertilizers that a certified organic farm can use. Sometimes they are more earth conscious, so for example, certain pesticides would not be allowed on a certified organic farm. Usually, it's more natural, but not always. There are many exceptions and many instances where certified organic farms are less sustainable. It's not necessarily always true that certified organic farms are safer or more natural. It depends 100% on the ethics of the grower.
  • Question
    How long do I need to soak seaweed to use it as fertilizer?
    Susan Butler
    Community Answer
    You can put kelp, or any seaweed, into a bucket or large glass jar and fill with water. Leave this in the sun, covered, for a few days and your ‘tea’ will be brewed. Use this as a foliar spray to deter insect pests, or apply directly to the soil around seedlings. Bear in mind that this concoction will smell bad, so be sure to store it downwind!
See more answers
Ask a Question
      Advertisement

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Thanks for submitting a tip for review!
      Advertisement

      Warnings

      Advertisement

      About This Article

      Thanks to all authors for creating a page that has been read 106,610 times.

      Reader Success Stories

      • Geraldine Costello

        Apr 19, 2018

        "I wish to use seaweed as it's a natural fertilizer and it's a natural local resource in abundance this ..." more
      Share your story

      Did this article help you?

      Advertisement