I’m sold on using seaweed fertilizer, whether fresh or purchased – and as people try it for themselves, they’re also learning its benefits.
As commenter Guian Millares writes:
“Dude it worked!!! My plants have grown very well with washed seaweeds! I use or twice everyweek and it is working awesome! Ive never had such growth before!! wow! Thanks man! God bless you….never listen to those who say negative things on you…You are doing great! God bless you.”
Thank you! God has blessed me and continues to do so. And I count the abundance of free local seaweed as one of those blessings.
A year ago I posted this video on making and using seaweed fertilizer in the garden:
Which reminds me: I have some new garden beds that could really benefit from some seaweed application. I’ll have to take a couple sacks with me next time I hit the beach with the family.
If you live far from the beach or don’t feel like hauling bags of seaweed, you can get good seaweed fertilizers on Amazon. is a popular one and is really rich since it’s a mix of both seaweed and fish. Fish emulsion is like magic in the garden – and when you mix it with seaweed, you’re really adding the bounty of the ocean to your plants. They go crazy. In fact, my friend Jo the Master Gardener once told me that fish emulsion is the way to grow truly awesome organic strawberries in Florida. It greens them up and makes them fruit without encouraging leaf growth over fruit.
Another option that I used to use on my beds in North/Central Florida was . It’s loaded with minerals and a little goes a long way. I don’t know if kelp is totally safe post-Fukushima, but I haven’t heard anything really scary lately.
I used kelp meal as part of the fertilizer mix I used to grow these amazing cabbages:
I followed the directions for making COF (Complete Organic Fertilizer) which Steve Solomon writes about in . Once I had my mix, I sprinkled it all down the beds, raked it in, put down a weed barrier, punched holes, then planted cabbage seedlings. They did better than any I’ve grown before or since. Absolutely beautiful heads.
Seaweed was part of that. Consider it a multivitamin for your garden, loaded with micronutrients. The big three – NPK – are the main course – and seaweed has those, but not in huge amounts – but seaweed is really rich in the little things which add to the overall health of your plants.
How to Make and Use Seaweed Fertilizer
So, you have some seaweed and want to try it out? Here are three good options.
Option #1: Seaweed as Mulch
Take the seaweed, rinse it out, then use it as mulch. That works nicely and breaks down over time. Maritime Gardening agrees:
Option #2: Compost it!
Put seaweed directly into the compost pile. Consider it a “green” layer. I don’t bother rinsing it when I do this, figuring the salt on it will work its way through.
Option #3: Make Liquid Seaweed Fertilizer
You’ve seen me do this before with weeds, manure, kitchen scraps, etc.:
But you can do it with seaweed as well. It’s a great additive – or it can be used all by itself.
This is a very good video where a man does the same method I do, but with comfrey and other northern leaves, along with seaweed:
Hey, that guy looks way more pro than me. I should send him a T-shirt.
Now go – find yourself some seaweed!