I had heard the buzz about using seaweed powder in the garden and have even fed my plants with sea kelp extract from time to time with excellent results. So when my boys asked me the other day if they could bring home some seaweed they found on a recent trip at the beach, I wondered…”Can I use that seaweed right in my garden as fertilizer?”
After a bit of investigating, I have found that we CAN use freshly harvested seaweed to feed the garden. You just have to get over the embarrassment of lugging home a bag of seaweed from the beach. Yes, people may stare at you, but this is for the betterment of the garden people! So if you live near an ocean and were thinking about collecting some seaweed for your garden, I am including the information here for you.
First, you should know that seaweed is a great fertilizer that contains both macro and micro-nutrients. It has the usual NPK of other fertilizers, as well as magnesium, zinc, calcium, sulfur, iron and copper. As it breaks down, it stimulates soil bacteria, and helps with aeration and moisture retention.
When harvesting seaweed, only collect the fresh pieces that wash up on shore. Old seaweed that has been sitting on shore for a few days will immediately be a host to sand fleas and other critters you do not want to haul home to your garden. It also gets smelly and slimy when sitting in the hot sun. Not a pleasant experience on the car ride home.
Another thing to consider is the fact that seaweed acts as a filter in the water. So if the water where you want to collect is highly polluted, the seaweed will absorb these pollutants. Think about this before adding harvested seaweed into your garden — especially if you grow edibles.
Once harvested, some people chop up the sea weed and add it directly to the garden. But this can attract animals and gets a bit slimy while decomposing. Instead, I recommend just adding the seaweed to your compost pile. Let the pile break it down and then add the nutrient rich compost to the garden. Some people don’t bother to rinse the seaweed first because the sea salts contain added nutrients, but I do not need more sand or salt in my soil. So I would rinse it first or soak it in a bucket of water before using it. Then just toss it into the compost pile…and wait.
I will let you know how this works out in my own garden…