Which plants like seaweed fertiliser – Explained

If you’re a seasoned gardener, I’m sure seaweed fertiliser isn’t a new term for you. However, for newbies, seaweed fertiliser is generally recommended by eco-friendly and organic farmers and gardeners. Made from the natural by-products of marine life, seaweed fertilisers are a wonderful option if you are looking for a sustainable way to fertilise your plants and bring down their carbon footprint. If you’re considering using seaweed as a fertilizer, you might be wondering, “Which plants actually like seaweed fertiliser?”.

seaweed fertilizers

Table of Contents

Which plants like seaweed fertiliser?

Simply put, all plants can benefit from seaweed fertiliser. It’s obvious that seaweed fertiliser is loaded with nutrients that are essential for the normal growth of plants. What makes the seaweed fertiliser stand apart is that it contains nutrients in large quantities – more than 40 minerals! From my experience, I’ve visibly noticed the effect of applying this fertiliser on my plants.

organic fertilizer

What is a seaweed fertiliser?

Seaweed fertiliser is an organic fertiliser that is made from seaweed extracts derived sustainably from the ocean. Gardeners and farmers who wish to use natural fertilisers and reap the benefits of organic gardening tend to use seaweed fertilisers on a large scale.

The best part about seaweed fertiliser is that it is packed with a variety of micronutrients and trace elements like calcium, phosphorus, potassium, and magnesium along with growth hormones including auxins and cytokinins. All of these are essential for the overall health of a plant. Aside from this, these nutrients help balance the NPK content (nitrogen, phosphorus, potassium) of the soil. So, there is absolutely no reason why you wouldn’t want to use this super-effective seaweed fertiliser in your garden.

fresh seaweed

What are the types of seaweed fertilisers?

Seaweed fertilisers are available in powdered, liquid, or granular forms of which liquid seaweed fertilisers are widely used. That’s mainly because liquid fertilisers seem to deliver quicker results compared to their solid counterparts. When it comes to solid fertilisers, they’ll have to first break down and become soluble; only then, plants can consume them. On the other hand, liquid fertilisers are readily available for plants.

Which plants like seaweed fertiliser?

To put it plainly, any and all plants can improve with seaweed fertilizer. Obviously, this type of fertilizer is rich in vitamins that are key for a plant’s typical growth. What makes seaweed fertilizer different from others is the number of nutrients contained within– often more than 40 minerals. I have first-hand experience with the noticeable difference in my plants after using this fertiliser regularly.

What’s more, this organic fertiliser has a positive effect on the ecosystem and the environment as well. While I said that all plants like seaweed fertiliser, there are a few plants for which it is more beneficial.

Flowering plants like geraniums and roses are known to benefit a lot by flowering more when seaweed fertiliser is used. You can see abundant blooms in these plants after using this organic fertiliser.

Seaweed nutrients make grapes sweeter and gladiolus corms larger. You can add seaweed fertiliser to your cucumber climbers and increase the yield by 40%. The natural fertiliser also prevents the cucumber fruits from softening and rotting too often. The same is the case with squash and pumpkins.

Planters of flowering plants like camellias, gardenias, rhododendrons, and azaleas claim that their plants largely benefit from seaweed fertiliser. Well, it’s mainly because seaweed nutrients acidify the soil and add iron to the soil, thereby helping the plants grow well.

Berries, like tomatoes, love seaweed fertiliser. Seaweed not only promotes healthy growth of the tomato plants but also prevents blossom end rot, the most commonly occurring problem in tomatoes.

Other fruits and vegetables that like seaweed fertiliser are lady’s finger, potatoes, sweet corn, strawberries, apples, oranges, and capsicum. In general, seaweed fertiliser is a great source of nutrients for almost all plants. So, all kinds of plants like this all-natural seaweed fertiliser.

plant health

How to apply seaweed fertiliser in your garden?

First, let’s consider liquid seaweed fertiliser. The best way to fertilise your plants using seaweed is to spray the liquid seaweed fertiliser on the leaves of your plants. Experts suggest that spraying this fertiliser on the leaves is more effective compared to adding it to the soil. However, be sure not to drench the plants with the fertiliser. You can lightly mist the leaves and the plants will absorb the fertiliser better. Note that you should spray the fertiliser on established plants and not on new plants that have less than three leaves.

When it comes to granular seaweed fertilizer or powdered seaweed fertiliser, understand that this form of seaweed takes longer to show the desired results on the plant. Make sure you adjust the concentration of the solid fertiliser depending on the plants. For example, if you intend to spray the entire lawn using solid seaweed fertiliser, you have to dilute it well so that it covers your whole lawn. If you want to use it on your indoor plants that need help, make sure you increase the concentration.

liquid seaweed fertilizer

What are the benefits of seaweed fertilisers?

There are many benefits to using seaweed fertiliser for your plants. Let’s have a look at the most important advantages that actually distinguish them from the others.

  1. Seaweed fertiliser is a rich source of nutrients. It contains large amounts of organic matter, vitamins, and minerals. Moreover, it contains alginic acid, which is capable of stimulating plant growth.
  2. Plants can absorb seaweed nutrients better. A great advantage of this organic fertiliser over its synthetic counterparts is that plants can absorb it in just 2-3 hours after application. This is highly beneficial for plants with nutritional deficiencies when an urgent remedy is required.
  3. Seaweed fertiliser is safe and organic. As this fertiliser is made exclusively from plant sources in marine waters, its origin is organic. Unlike chemical fertilisers, it doesn’t leave any residues or harmful substances that affect plants. It is safe and great for the environment.  
  4. Seaweed fertiliser enhances soil quality. A large amount of organic matter found in seaweed fertiliser accelerates the activity of various microorganisms present in the soil, eventually making it more fertile and resulting in a quality ecosystem.
chemical fertilizers


Which plants like seaweed fertiliser?” To recap, this amazing fertilizer can do wonders for your plants. Key points to remember are::

  • Seaweed is a great choice if you want to use an all-natural, eco-friendly fertiliser that will provide your plants with the boost they need. 
  • Seaweed is a rich source of nutrients, which are essential for the overall growth of the plant.
  • Be sure to follow the manufacturer’s instructions before you use the seaweed fertiliser in your garden for maximum results.
seaweed species

People also ask

How often should you use seaweed fertiliser?

The general rule of thumb is that you should use seaweed fertiliser every two or four weeks to ensure your plants are obtaining the required nutrients without getting overloaded. While that’s the general rule, proper observation and common sense play a major part. You will have to keep a watch over your plants as well as the soil conditions to see how they are responding to the fertiliser treatment.

If you see that your plants are lacking a healthy look, you may have to increase the frequency of fertiliser application. In the same way, if you notice your plants growing too quickly or appearing to be burning, you may have to step back on fertiliser use a bit. You can soon find the right balance for your garden with some trial and error.

Should you rinse seaweed before using it in the garden?

You don’t have to rinse seaweed fertiliser before using it in the garden. If you rinse, the important minerals in the fertiliser may be washed out, and the plants may not get the nutrients required for optimal growth.

Can seaweed be toxic?

Research suggests that so far, there isn’t any evidence that seaweed can be hazardous or toxic. Seaweed is obtained from sea algae, which do not contain any poisonous alkaloids that might cause toxic effects on plants, animals, or humans.

Does seaweed fertiliser burn plants?

Seaweed fertiliser can burn plants only when it is applied heavily or in direct sunlight. If used as directed by the manufacturer, it will not burn plants. As mentioned earlier, seaweed is a natural fertiliser that’s rich in organic matter, minerals, and vitamins that are essential for the healthy growth of plants. In fact, it also has hormones and trace minerals that improve the plant’s resistance to disease and pests. Also, as this natural fertiliser is a slow-release fertiliser, it doesn’t burn plants like a few chemical fertilisers. On the whole, it serves as an excellent organic fertiliser that offers numerous benefits to plants.

What is the pH of seaweed?

The pH level of seaweed is 9.0 once digested. It’s because sea vegetables belong to the alkaline food group. Kelp, dulse, and wakame tend to be highly alkaline.

Can you use seaweed fertiliser for succulents?

Of course, yes. Seaweed is a great fertiliser for succulents. It is perhaps a direct source of protein for plants. So, when you use seaweed for your succulents, they will grow healthier, larger, and more beautiful.

Is seaweed fertiliser acidic or alkaline?

Seaweed fertiliser exhibits a neutral to slightly alkaline pH. Therefore, it helps neutralise acidic soil and is a great fertiliser for seaside gardens, the soil of which is often acidic.

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Oliver Wright
Oliver Wright

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