Vertical Garden Fertilisers: Reviews of the Top 7 in Australia

Discovering the Right Fertiliser for Your Vertical Garden

Vertical gardening is a fantastic way to maximise space and add a splash of natural beauty to your home. But, growing your favourite plants in such conditions presents some unique challenges, especially when it comes to nutrition.

Two specific issues arise due to the nature of vertical gardens:

1. There’s typically less soil or other growth mediums available for each plant.
2. Water drains more quickly from vertical setups compared to traditional garden beds.

Both factors can lead to faster nutrient depletion, and your plants may struggle if they aren’t receiving enough nourishment to support their growth. But worry not! With the right fertiliser, you can ensure your vertically grown plants are healthy and thriving.

We’ve done the research to help you discover the best vertical garden fertilisers on the market. We’ve reviewed all purpose fertilisers suitable for soil-based vertical gardens in this article. Our top seven picks, based on criteria such as efficacy, value for money, availability, ease of use, and environmental impact, are sure to help your vertical garden flourish.

And if you are looking for more information about fertilisers, (like how to read the confusing fertiliser labels!) and how to choose the right vertical garden fertiliser for your garden we have this covered later in this article.

To learn more about using vertical garden fertilisers, we’ve created a full article on it as we know this is an important area to understand for success for your vertical garden. Let’s dive in and find the perfect feed for your plants!

Criteria for Vertical Garden Fertiliser Evaluation

Before jumping straight in and sharing our recommendations, there were several factors we considered when evaluating different fertilisers:

1. Efficacy: How well does the fertiliser promote plant growth and yield? We assess its performance by considering user reviews and, where possible, conducting our own trials.
2. Value for Money: Is the fertiliser reasonably priced for the value it offers? A cheap fertiliser might seem attractive initially, but if it doesn’t provide the desired results or requires frequent reapplication, it might not be cost-effective in the long run.
3. Availability: How easily can the product be obtained by Australian gardeners? We prioritise products that can be conveniently sourced either through local gardening stores or reliable online platforms.
4. Ease of Use: How user-friendly is the product? Clear instructions for correct application are vital to ensure the best results and avoid potential damage to plants.
5. Environmental Impact: What is the product’s environmental footprint? Does it contribute to nutrient runoff affecting the broader ecosystem, or is its packaging minimal and recyclable? As gardeners, it’s essential to consider the broader environmental implications of the products we use.
6. Health Impact: Are there any potential health implications associated with the product? Some fertilisers can leave residues that accumulate in the food chain, posing potential health risks. We consider the safety of the product based on its ingredient list and any reported health-related concerns.

With these criteria in mind, we’ll now move on to our top fertiliser recommendations for vertical gardens in Australia. We’ve considered the products based on the factors mentioned above to help you make an informed choice. And if you don’t know what the N-P-K ratio which we refer to in our reviews, check out our description on fertiliser labels.

Best Vertical Garden Fertilisers for 2023 – Reviewed

1. Best Quick-Acting Inorganic Fertiliser: Miracle-Gro Water Soluble All Purpose Plant Food

Miracle-Gro’s All Purpose Plant Food is a popular, water-soluble fertiliser that’s effective on a wide range of indoor and outdoor plants. This synthetic fertiliser is designed to be mixed with water and applied using a watering can or sprayer to the base of the plant.

The product has an N-P-K ratio of 24-8-16, and it also includes several micronutrients like Magnesium, Copper, Iron, Manganese, Zinc, and Molybdenum. This broad spectrum of nutrients makes it suitable for a wide range of plants. Its high level of phosphorus makes it unsuitable to use on Australian natives. Its water-soluble nature ensures rapid nutrient absorption, promoting quick and robust plant growth. However, because of its fast action, it requires frequent application (every 1 to 2 weeks), increasing its long-term cost.

User reviews highlight the significant plant growth and health improvement after use. Some customers note its easy use and the convenience of the water-soluble form. However, some have expressed concerns over the synthetic composition, which might leave residues. Overuse can lead to nutrient runoff, affecting water quality in the surrounding environment so make sure you don’t have pets or children that will drink or play in any drips or pools of water coming from your vertical garden. Always follow the application instructions to minimise these risks. Its packaging is recyclable.

2. Best Slow-Release Inorganic Fertiliser: Scotts Osmocote Plus Trace Elements

Scotts Osmocote Plus is a slow-release inorganic fertiliser that is known for its long-lasting nutrient delivery. It comes in a granule form sprinkled on soil and only requires application once per year making it a low-maintenance fertiliser.

Its N-P-K ratio of 21-0.5-6, along with a blend of 11 essential nutrients, provides balanced nutrition. Nutrients include Calcium, Magnesium, Sulphur, Boron, Copper, Iron, Manganese, Molybdenum, and Zinc.
The product releases the nutrient in line with a plant’s natural growth cycle. This helps to reduce the risk of over or under-fertilisation and makes feeding your plants less labour-intensive, as applications are required less frequently (once per year).

Customer reviews note its ease of use and effectiveness, observing noticeable improvements in plant health. Its slow-release formulation requires less frequent application, proving cost-effective over time. However, like all inorganic fertilisers, it doesn’t contribute to soil health in the long term.

Environmentally, over-application can contribute to nutrient runoff. However, its slow-release nature reduces this risk. The packaging is recyclable, reducing waste. While the fertiliser is synthetically produced, following the manufacturer’s usage instructions will minimise potential health risks and environmental impact.

3. Best Marine-Based Organic Fertiliser: Neptune’s Harvest Organic Fish & Seaweed Fertiliser

Neptune’s Harvest is a fully organic, liquid fertiliser that combines the benefits of fish and seaweed. It provides a balanced array of nutrients and natural growth promoters that help to improve plant health, stimulate robust growth, and increase yield.

Its N-P-K ratio is 2-3-1, and it’s packed with trace minerals, amino acids, and vitamins that help stimulate plant growth and improve resilience (including Calcium, Magnesium, Sulphur, Boron, Copper, Iron, Manganese, Zinc, and Molybdenum).

Customers find it effective and easy to use, with many noting significant improvements in their plants’ health and growth and quality of produce. However, some users find the smell of this fertiliser off-putting, a common issue with organic, fish-based products. This smell usually disappears after application.

As an organic product, it poses little to no risk to human health. Also, its organic nature makes it a sustainable choice with a lower environmental impact as it doesn’t contribute to nutrient runoff or contamination of water.

4. Best Organic Granular Fertiliser for Soil Health: Jobe’s Organics Purpose Granular Fertilizer

Jobe’s Organics 09524 Purpose Granular Fertiliser is an organic fertiliser that has won the hearts of many gardeners due to its well-balanced nutrient profile and favourable impact on soil health. This product provides an even and sustained nutrient release, aligning well with the life cycle of most plants and preventing problems related to over or under-fertilisation.

In terms of nutritional content, Jobe’s Organics 09524 features an N-P-K ratio of 4-4-4, indicating a balanced supply of Nitrogen, Phosphorus, and Potassium. It also offers a good range of secondary nutrients and trace elements, including Calcium, Magnesium, and Sulfur, which are necessary for plant health.

Feedback from customers notes the product’s effectiveness in improving both plant growth and the condition of the soil. Users frequently observe noticeable improvements in plant vigour and yield after applying this fertiliser. Many gardeners appreciate the added bonus of its positive long-term effects on soil structure and microbiology due to its organic composition.

As with all organic fertilisers, it may not deliver nutrients as rapidly as inorganic options, potentially leading to slower initial growth. However, its enduring benefits for soil health and sustainability often outweigh this minor limitation, making this fertiliser a top choice for gardeners focused on organic and sustainable practices.

5. Best Hybrid Organic-Inorganic Fertiliser: Yates Thrive Natural Fish & Seaweed+ Hose On

Yates Thrive All Purpose Natural Fish & Seaweed+ Hose On is a dual-action liquid fertiliser formulated for use on all garden plants throughout the year. This features a blend of over 50% natural organic ingredients, including sustainably sourced fish and seaweed from the southern oceans of Australia.

The fertiliser has an N-P-K ratio of 2-0.5-1 and incorporates trace elements and natural growth stimulants that promote overall plant health, vigorous growth, and resilience to stress. The fertiliser feeds plants both through the leaves and roots, resulting in fast, visible results. The low level of phosphorus means it can be used on Australian natives.

Customer reviews frequently highlight substantial improvements in plant growth and overall health following the product’s application. The fertiliser’s ease of use, owing to its liquid form and rapid absorption by plants, is often appreciated. Users note that the scent, characteristic of fish emulsion fertilisers, can be quite potent, although this is a common trait of such products.

Yates Thrive Natural is safe for use around pets and children due to its largely organic composition. It also contributes to the enrichment of the soil, fostering a healthier garden ecosystem. This fertiliser is a popular choice for a variety of plant types, from vegetables and flowers to shrubs, particularly in Australia where the Yates brand is well-recognised and widely accessible.

6. Best All Round Organic Fertiliser: Organic Xtra Premium

Organic Xtra Premium Pellets is an Australian-made organic fertiliser that stands out for its comprehensive blend of composted poultry manure, blood & bone, fish meal, seaweed, and natural minerals. With an NPK ratio of 4:1.5:3, it’s designed to deliver optimum levels of essential nutrients to your plants.

The fertiliser has a slow-release formulation, which aligns with your plants’ natural growth cycles, reducing the risk of over-fertilisation and ensuring that your plants are nourished over an extended period. Moreover, it’s gentle on plants, meaning it won’t cause burn, even if not watered in immediately.

It comes in a pelleted form that’s easy to apply and is compatible with fertiliser spreaders. Its uniform size and sieved nature minimise dust and make it suitable for every plant in your garden.

Organic Xtra users often notice increased worm activity and improved water retention in their soil, indicative of healthy soil biology. The product is certified by Biological Farmers of Australia, so you can trust its organic integrity.

While its nutrient release may be slower than some inorganic options, its benefits to long-term soil health and the broader environment make Organic Xtra a solid choice for organic gardeners.

7. Best Long-Lasting Organic Fertiliser: Aptus BaseBoost

Aptus BaseBoost is a time-release organic fertiliser that stands out for its simplicity, longevity, and comprehensive nutrient profile. It is often used in hydroponic gardens but performs equally as well in soil. This highly concentrated fertiliser is designed to serve even the most demanding plants for up to three months, while less demanding species can benefit for over six months.

The product has a N-P-K ratio of 6-3-13 and includes L-amino acids, which are known to stimulate cellular immunity in plant development and sets BaseBoost apart from many other fertilisers. It also incorporates secondary macro-nutrients such as Calcium, Magnesium, and Sulphur, along with organically chelated micro-nutrients like Boron, Iron, Manganese, and Zinc.

The product performs well across a range of various growing conditions and regions, making it a good choice for areas with challenging soil conditions. BaseBoost poses minimal risk of burning or overdosing, which users value for peace of mind.

Customer reviews frequently highlight the visible improvement in plant health and growth following the application of BaseBoost. Many appreciate its easy application, long-lasting effects, and organic formulation. Plus, with its long shelf life when stored properly, and concentrated form, BaseBoost offers excellent value for money. It’s worth noting that this product can take a week or two to kick in fully.

Please note that the exact nutrient composition can vary between batches and that not all trace nutrients might be listed on the product label. Always refer to the product’s most recent label and consult with a local extension service or gardening expert if you’re unsure.

What You Need to Know About Vertical Garden Fertilisers Before Making Your Choice

What are the Different Types of Nutrients in Fertilisers?

Fertilisers are substances added to the soil or applied to plants directly to provide essential nutrients that they need to grow and thrive. Just like humans need a balanced diet to stay healthy, plants also require certain nutrients to maintain their growth, vitality, and ability to withstand diseases.

Primary Macronutrients

The three most vital nutrients that plants require are nitrogen (N), phosphorus (P), and potassium (K), often represented as the N-P-K ratio on fertiliser labels.

• Nitrogen (N) is crucial for the growth of leaves and stems. It’s part of every protein in the plant, so it plays a role in key growth processes. Without sufficient nitrogen, plants become stunted, with yellowing leaves and slow growth.
• Phosphorus (P) is required for energy transfer and storage in the plant. It’s also necessary for cell division and plant growth. Plants deficient in phosphorus may exhibit stunted growth and a darker than normal colour.
• Potassium (K) is essential for overall plant health as it plays a role in regulating water and nutrient movement in plant cells. It also aids in disease resistance, protein production, and fruit quality. A deficiency might cause weak stems and slow growth.

In addition to these primary macronutrients, there are secondary macronutrients and micronutrients (also called trace elements) which, although needed in smaller quantities, are still essential for plant health.

Secondary Macronutrients

Secondary macronutrients include calcium (Ca), magnesium (Mg), and sulphur (S). These nutrients are generally available in the soil but might need to be added if the soil is deficient.

• Calcium (Ca) aids in cell growth and division, affecting the plant’s overall growth. A deficiency can cause stunted growth and browning at the growing tips.
• Magnesium (Mg) is a part of chlorophyll, the compound that plants use to convert sunlight into sugars for food during the process of photosynthesis. Without sufficient magnesium, plants may begin to show signs of yellowing between the leaf veins.
• Sulphur (S) is necessary for the production of certain amino acids and proteins. A deficiency in sulphur could lead to stunted growth and yellowing of leaves.

Trace Elements

Micronutrients or trace elements include boron, copper, iron, chloride, molybdenum, manganese, and zinc. They play various roles, from assisting in photosynthesis to aiding in the formation of certain enzymes. While deficiencies in these nutrients can harm plant growth, they are usually present in sufficient quantities in most soils or can be added via specific trace element supplements if needed.

Importance of Achieving a Balance of Nutrients in Vertical Gardens

In a vertical garden, maintaining a balance of these nutrients is vital due to the limited soil volume and rapid drainage. Some nutrients might leach out with water, and because the plant’s root space is restricted, they may exhaust their nutrient supply more quickly than plants in traditional garden setups. This makes choosing the right fertiliser and understanding your plants’ specific nutrient needs critical to the success of your vertical garden.

When growing food in your vertical garden, nutrient deficiencies can not only affect the quantity of the produce but also its quality, including taste and nutritional content. For example, a potassium deficiency might lead to less tasty fruits, while a lack of iron might decrease the nutritional content of your leafy greens. This makes using the right fertiliser and nutrients even more critical for vertical gardens intended for food production.

Types of Fertilisers

Fertilisers come in different forms, each with benefits and potential downsides. The type that’s best for your vertical garden depends on your specific circumstances, including your plants’ needs, your gardening goals, and your personal preferences.

1. Organic Fertilisers:

Derived from plant, animal, or mineral sources, organic fertilisers provide nutrients in a form that’s gentle on plants and beneficial to the soil’s health. They release their nutrients slowly, providing a sustained supply over a longer period. This slow release can support the health of the soil and its microbiome, contributing to overall plant health. They’re also less likely to cause nutrient runoff that can harm the environment. However, the nutrient ratios in organic fertilisers can be inconsistent, and they may not provide nutrients as rapidly as inorganic options, which could potentially lead to slower growth rates.

2. Inorganic Fertilisers:

These are commercially produced fertilisers made from mineral salts. They contain concentrated amounts of specific nutrients and can deliver them to plants quickly. This makes them useful in a vertical garden, where space is limited and nutrients can be depleted rapidly. But this potency comes with risks: Overuse of inorganic fertilisers can lead to nutrient runoff that can harm the environment, and the buildup of salts in the soil could potentially damage plants over time. Always follow the manufacturer’s instructions to avoid these problems.

3. Liquid Fertilisers:

These fertilisers, which can be either organic or inorganic, are often favoured by vertical gardeners. The liquid form allows for easy application and quick absorption by plants, providing an immediate nutrient boost when needed. However, because the nutrients are available immediately, they’re used up more quickly and need to be reapplied more frequently.

Understanding Fertiliser Terms

You’ll encounter several common terms when choosing a fertiliser for your vertical garden. Understanding these terms can help you make the best choice for your plants:

• Slow-Release: This term refers to fertilisers that release their nutrients slowly over time, usually over a period of weeks or months. Slow-release fertilisers, often in granular form, are coated in a material that breaks down slowly, gradually releasing the nutrients. These fertilisers can be particularly useful for long-term nutrient supply, reducing the need for frequent reapplication.
• Water-Soluble: These fertilisers dissolve in water and are quickly available to plants. They can be applied to the soil or used as a foliar spray (sprayed over a plant’s leaves instead of adding it to the soil). They provide an immediate nutrient boost, making them useful for correcting deficiencies or supporting fast growth. However, they typically need to be applied more often than slow-release fertilisers.
• Controlled-Release: Similar to slow-release fertilisers, controlled-release fertilisers are coated in a semi-permeable shell that allows water to enter, dissolve the nutrients, and then slowly release them into the soil. The release rate is determined by factors like soil moisture and temperature.
• Granular: Granular fertilisers are solid particles that are spread onto the soil and then watered in. They can be slow-release or quick-release, depending on their formulation.
• Complete: A complete fertiliser contains all three primary nutrients—nitrogen, phosphorus, and potassium. However, the term doesn’t guarantee that the fertiliser contains any of the secondary or micronutrients that plants also need.
  In the next section, we’ll explore how to read fertiliser labels to better understand the nutrient content of these products.

Understanding Fertiliser Labels

When we got started with gardening and tried to buy fertiliser, we had no idea what we were looking for – and the labels on the range of packets didn’t do much except confuse me more! Deciphering the information on a fertiliser package is crucial for selecting the right product for your vertical garden’s needs. Here are the key details:

1. N-P-K Ratio:

Fertiliser labels usually show three numbers separated by dashes (e.g. 10-10-10). These numbers repressent the ratio of the primary nutrients—Nitrogen (N), Phosphorus (P), and Potassium (K), respectively.This ratio is always in the same order and indicates the percentage by weight of each nutrient. For example, a 10-10-10 fertiliser contains 10% Nitrogen, 10% Phosphorus, and 10% Potassium. The remaining 70% comprises secondary nutrients, micronutrients, and filler material.

 Each of these nutrients has an important role in plants:

• Nitrogen: Nitrogen is primarily responsible for leaf and stem growth, and it’s also crucial for the overall size and vigour of the plant.
• Phosphorus: Phosphorus helps plants to grow strong roots and gives them the energy to bloom brightly and produce lots of fruit and seeds. It’s vital for their overall health and growth.
• Potassium: Potassium strengthens plants’ overall resilience. It improves drought tolerance and disease resistance.

2. Secondary Nutrients and Micronutrients:

While not always listed, some fertilisers will indicate the presence of secondary nutrients (calcium, magnesium, and sulphur) and micronutrients (iron, manganese, zinc, copper, molybdenum, boron, and chlorine). These nutrients are essential for plant health, though in smaller quantities than the primary nutrients.

3. Organic or Inorganic:

The label will also usually indicate whether the fertiliser is organic or inorganic. Organic fertilisers come from natural sources and release nutrients slowly, while inorganic fertilisers are synthetically produced and provide quick, concentrated doses of nutrients.

You may see some of the other terms on the label like slow-release and we covered what these mean in the above section.

How to Choose the Right Fertiliser for Your Vertical Garden

The choice of the right fertiliser for your vertical garden involves more than just picking up any bag off the shelf. There are several key factors to consider:

Consideration of the Plant Types in Your Garden:

The nutrient requirements of plants vary based on their species and life stages. Leafy vegetables, for instance, have a high demand for nitrogen, essential for foliage growth. In contrast, fruiting plants like tomatoes require higher concentrations of phosphorus and potassium during their flowering and fruiting stages.

Some plants, such as many Australian natives, are also sensitive to certain nutrients like phosphorus. Research each plant type in your vertical garden to understand their specific nutritional needs and sensitivities. The fertilisers we have reviewed in this article are all purpose fertilisers but you can also purchase one’s more specialised for what you are growing (such as tomatoes).

The Role of Soil Testing in Fertiliser Choice:

Soil testing is an underutilised but highly valuable tool for gardeners. It reveals the pH of your soil and the levels of primary nutrients, namely nitrogen, phosphorus, and potassium. More comprehensive tests can also determine secondary and trace nutrient levels. This information is essential as even with adequate nutrients, if your soil pH is off, plants might not be able to take up those nutrients effectively. Accordingly, you can choose a fertiliser that supplements missing nutrients or balances excessive ones.

Organic versus Inorganic Fertilisers:

Depending on your gardening style and plant preferences, you might opt for organic or inorganic fertilisers. Organic options including seaweed and blood and bone options, compost or manure offer a broad range of nutrients and improve soil health over time. On the other hand, inorganic fertilisers often provide immediate nutrient availability and specific nutrient ratios, but do not contribute to the long-term soil health. Our preference is for organic fertilisers based on the long term benefits they deliver without using synthetic compounds. Organic fertiliser are better for the environment and better for our health.

Practical Factors:

Your budget, the availability of the fertiliser in your region, and your convenience and gardening style matter too. For instance, would you prefer a slow-release granular fertiliser that requires fewer applications, or are you more inclined towards frequent applications of a quick-acting liquid fertiliser?

Choosing the right fertiliser requires a balance of all these factors. Remember, there’s no one-size-fits-all fertiliser. Matching the right kind of fertiliser to the right plant will help ensure your plants get the nutrients they need to thrive, especially in a vertical garden where soil volume and nutrient reserves may be limited.

Applying Fertilisers in Vertical Gardens

a) How to correctly apply fertilisers in a vertical garden

The correct application of fertilisers in a vertical garden can make the difference between plant success and failure. Always follow the manufacturer’s instructions regarding the rate of application. For granular fertilisers, you might need to gently work the granules into the top soil layer, being careful not to damage plant roots. Liquid fertilisers, on the other hand, are typically diluted with water and applied to the soil or even foliage. Always water in your fertiliser unless the label instructs otherwise. This helps the nutrients to start dissolving and become available to plant roots.

b) Consider the soil pH

Don’t neglect soil pH. Nutrient availability is greatly influenced by soil pH. Even with adequate nutrients, if your soil pH is off, plants might not be able to take up those nutrients effectively.

You can measure pH with a soil pH kit from a nursery or online and adjust the soil’s pH level based on the reading and the plants you are growing. For example, if your soil is too acidic, you can add lime (calcium carbonate) to raise the pH. If it’s too alkaline, you can lower the pH by adding substances like sulphur or organic matter such as compost or manure.

c) Common mistakes with fertilising

Avoid the common mistake of over-fertilising. More isn’t better; excessive nutrients can harm plants and lead to environmental runoff. Under-fertilising, especially in a nutrient-demanding environment like a vertical garden, can also be detrimental.

Conclusion: Nurturing Your Vertical Garden

Choosing and using the right fertiliser for your vertical garden is a significant determinant of your gardening success. By considering the specific needs of your plants, the current state of your soil, and practical factors like cost and convenience, you can select a product that will support healthy, vigorous plant growth. Proper application is just as critical. Remember, the goal is to supplement the soil with what it lacks, not to overload it with excess.

Ultimately, the best fertiliser for your vertical garden will depend on your specific needs, including your plants’ nutrient requirements, your commitment to organic or inorganic gardening, and your preference for slow-release versus fast-acting fertilisers. As always, it’s crucial to consider all these factors when deciding on the best fertiliser for your situation.

Gardening is as much a science as it is an art. While there’s much to consider when choosing and applying fertilisers, remember that every garden and gardener is unique. Use the principles shared here as a starting point, but don’t be afraid to experiment, learn from experience, and adapt these recommendations to your situation.

FAQs for Fertilisers for Vertical Gardening