How to use seaweed compost for acid and alklaline plants

Here’s how seaweed compost interacts with different types of plants and how to use it effectively for both acid and alkaline soil conditions.

Seaweed compost for both acid and alkaline plants

Seaweed compost is an excellent organic amendment that can benefit both acid-loving and alkaline-loving plants due to its rich nutrient profile and neutral pH. Here’s how seaweed compost interacts with different types of plants and how to use it effectively for both acid and alkaline soil conditions.


Benefits of Seaweed Compost for Both Acid and Alkaline Plants


Nutrient-Rich: Seaweed compost is high in essential nutrients such as nitrogen, potassium, phosphorus, and trace elements like magnesium, iron, and zinc. These nutrients support overall plant health and growth, regardless of soil pH.

Soil Structure Improvement: Seaweed compost enhances soil texture, improving aeration and water retention, which benefits all types of plants.

Growth Hormones: Contains natural growth hormones like cytokinins, which promote root growth and improve plant resilience.


Using Seaweed Compost for Acid-Loving Plants

Examples of Acid-Loving Plants: Blueberries, azaleas, rhododendrons, camellias, and gardenias.

Application Tips:

Soil Preparation: Mix seaweed compost into the soil before planting acid-loving plants. While seaweed compost has a neutral pH, it will not alter the soil’s acidity significantly, allowing acid-loving plants to thrive.

Mulching: Apply a 2-3 inch layer of seaweed compost around the base of acid-loving plants to help retain moisture and add nutrients gradually.


Using Seaweed Compost for Alkaline-Loving Plants

Examples of Alkaline-Loving Plants: Lavender, rosemary, cabbage, and spinach.

Application Tips:

Soil Amendment: Incorporate seaweed compost into the soil around alkaline-loving plants to improve nutrient availability and soil structure. Its neutral pH ensures that it won’t make the soil more acidic.

Top Dressing: Use seaweed compost as a top dressing around alkaline-loving plants to slowly release nutrients over time.

Mulching: Similar to acid-loving plants, a layer of seaweed compost as mulch can benefit alkaline plants by maintaining soil moisture and adding nutrients.


General Tips for Using Seaweed Compost

Balancing with Other Amendments: If you have very acidic or very alkaline soil, consider balancing seaweed compost with other organic matter that suits the specific pH needs of your plants. For example, peat moss for acid-loving plants or lime for alkaline-loving plants.

Regular Monitoring: Regularly test your soil pH to ensure it remains within the optimal range for your plants. Adjust your composting and soil amendment practices accordingly.

Avoid Overuse: While seaweed compost is beneficial, using too much can lead to nutrient imbalances. Apply it in moderation and in combination with other organic materials.


Seaweed compost is a versatile and nutrient-rich amendment that supports the growth of both acid-loving and alkaline-loving plants. By following best practices in application and monitoring soil conditions, gardeners can optimise the benefits of seaweed compost, ensuring healthy and productive plants across various soil types.


Buy our organic peat-free seaweed-enriched compost in 100% compostable packaging today (includes free delivery to UK mainland postcodes).

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