Seaweed is rich in micronutrients and plant growth hormones, which makes it an incredible fertilizer for both outdoor and indoor plants.[1] One easy way to take advantage of seaweed’s plant-boosting properties is to brew a liquid seaweed fertilizer, or “seaweed tea.” Making your own seaweed tea is super easy, all-natural, and pretty fun, too! Keep reading to learn how to make liquid seaweed fertilizer from either fresh or dried seaweed, plus how to use it to grow a greener, more beautiful garden.

Things You Should Know

  • Use washed-up seaweed collected from the beach or dried, unroasted seaweed to make your fertilizer.
  • Soak the seaweed in a bucket of water for at least 4 weeks.
  • Dilute the seaweed fertilizer with water and use it to water your outdoor and indoor plants.

Collect seaweed.

  1. This is the fun part! Head to the beach with a bucket or bag and collect seaweed that’s washed up on shore. Just make sure to check your local laws online first—in some places, it’s illegal to collect seaweed on the beach, or there’s a limit to how much you can collect in one day.[2]
    • If you can’t make it to a beach or collecting seaweed isn’t allowed in your area, order dried (but unroasted) seaweed online and use that to make your fertilizer tea instead.[3] It will still have all the same plant-boosting nutrients as fresh seaweed.
    • Only collect seaweed that’s washed up on shore. Pulling up live seaweed can harm the local ecosystem.[4]
  2. Advertisement

Use the seaweed tea to fertilize your garden.

Community Q&A

  • Question
    Can I use any seaweed to make fertilizer?
    Community Answer
    Community Answer
    Yes, you can.
  • Question
    I bought seaweed tea sheets, how do I prepare it for drinking?
    Community Answer
    Community Answer
    The tea described in this article is liquid fertilizer for plants, do not drink it.
  • Question
    Is seaweed liquid fertilizer good for a cacao plant?
    Community Answer
    Community Answer
    Yes. seaweed liquid extract is good for all plants.

Things You'll Need

  • Seaweed (fresh or dried)
  • Bucket

About This Article

Ben Barkan
Reviewed by:
Garden & Landscape Designer
This article was reviewed by Ben Barkan and by wikiHow staff writer, Kyle Hall. 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, is licensed Construction Supervisor in Massachusetts, and is a Licensed Home Improvement Contractor. He holds an associates degree in Sustainable Agriculture from the University of Massachusetts Amherst. This article has been viewed 155,717 times.
11 votes - 86%
Co-authors: 10
Updated: February 23, 2023
Views: 155,717
Categories: Fertilizers