A lot of giant pumpkin growers are new growers, or growers that haven’t taken it to the next step.
This is because the next step can feel like a giant leap.. Soil tests, lots of products, foliar tests etc, you need all those things if you want a record breaking pumpkin.
But if your not at that level, and you want to help your pumpkin, look no further than seaweed fertiliser. In this post I will talk about what seaweed fertiliser is. How it can help your plant and why it is a great first product to be using on your giant pumpkin plants.
What is Seaweed Fertiliser?
It is a fertiliser (liquid, powder and granules) that has the core ingredient of seaweed. There are over 12,000 different varieties of seaweed in the ocean (according to Wikipedia), this seaweed is rich in nutrients. Some versions are organic, while others aren’t. But this is a good option to look at if you want to be as organic as possible.
These nutrients can help your pumpkin and plant grow more, as well as help with plant health.
What is Seaweed/Fish Fertiliser?
This fertiliser combines the benefits of seaweed with the added goodness of fish. Now is this a marketing gimmick? Or just a side effect of harvesting seaweed? I’m not sure. Remember to read the labels to compare the nutrient make up of the product.
What is the make up of Seaweed Fertlisers?
It seems a lot of products don’t list the NPK of the product. I’m unsure if this is due to potential variability between batches, or it’s a lot harder to work out than a 100% man made fertliser.
One product does have NPK as 9-5-9 on the packaging. This could be used as a super rough guideline.
What are the benefits of using it on your giant pumpkin plant?
There are a lot of benefits of using a seaweed or seaweed & fish based fertliser on your pumpkin patch, like:
- This product goes a long way. 500ml of liquid product can usually make over 200L of ready to use product. Powdered product also goes a long way.
- It’s safer to store, handle and use compared to other fertlisers out there. There’s also organic versions as well.
*Lots of choice of product out there. Which means there are a lot of pack sizes that work for people no matter how big your pumpkin patch is. - Using a product like this is a lot more forgiving than say a 100% man made product focused only on one mineral or nutrient. This makes it a better choice for new growers.
- Multipurpose, can be used on all sorts of plants
- Able to combine with other products
- Improves plant health
What products are out there?
Over the years there seems to be a lot more seaweed based products out there.
If I was to guess why, it might be due to the these reasons:
- It could be cheaper to produce than a traditional non natural product
- People want easier to apply, more organic products
Every brand out there will have some sort of seaweed or seaweed and or fish based fertiliser.
I have noticed that recently a lot of these products are now called tonics. I’m not sure if this is a marketing term to help sales, or to differentiate themselves from fertlisers.
Use on Your Whole Garden
You can pick up a majority of them from any home improvement store, some brands can ship product to you from their website. Research what is out there, and what sized the packs come in. Seaweed and fish based fertlisers can be used on most plants and produce good results. Picking up more to use on everything might work out cheaper.
Here is a bunch of different seaweed fertlisers I found that are available here in New Zealand (at the time of writing). They are in no particular order, and I don’t endorse any of them. This list is to help show you what is out there at the time of writing this blog post.
Wet and Forget Organic Seaweed Tea and Organic Seafood Soup
Tui Seaweed & Fish Fertliser
Garden Basics Seaweed Liquid Fertliser Concentrate
Yates Thrive Natural Seaweed Tonic
Yates Thrive Natural Fish & Seaweed+ Plant Food Concentrate
Tui Organic Seaweed Plant Tonic
Grosafe Bio Power Seaweed Flake Concentrate
Ocean Organics Seaweed Products
Garden Time 1L Liquid Feed with NZ Natural Seaweed
Seasol Concentrate 2L
Is there a product you love using that I don’t have listed? Let me know by leaving a comment and I’ll add it in.
If you are near the ocean and have access to seaweed you could use it in it’s natural form. Without the need for buying products. There are a lot of resources out there on how best to use it.
One good resource to get you started is this article on the thisNZlife website
In conclusion
If you aren’t using some sort of seaweed based product during your growing season, you should be.
There is a lot of products out there. Find one that fits within your budget. Like every other fertiliser or gardening product out there follow the instructions. You might be tempted to use more product. This could harm your plants, or more likely you are throwing money away.
Seaweed is a great natural product which provides a lot of benefits to your pumpkin patch.

Growing giant pumpkins is a passion that I love sharing. 🎃 If you’ve found my content helpful or entertaining, why not say thanks with a coffee? ☕
It’ll fuel my next giant pumpkin adventure!