Healthy plants need more than sunlight and water—they also need the right balance of nutrients to thrive. In traditional gardening, soil provides most of these nutrients, but in hydroponics, we deliver them directly to the plants through fertiliser. Choosing and using the right fertiliser is key to making sure your hydroponic garden stays green, productive, outdoor hydroponic system and full of life.
What is Plant Fertiliser?
Fertiliser is essentially food for your plants. It contains the essential elements they need for growth, development, and fruiting. While different plants have slightly different needs, there are three main nutrients—known as macronutrients—that are most important:
- Nitrogen (N) – Promotes leafy growth and strong stems.
- Phosphorus (P) – Helps with root development and flowering.
- Potassium (K) – Supports overall plant health, fruiting, and disease resistance.
These three nutrients are often written as the “NPK ratio” on fertiliser packaging. A balanced fertiliser will provide all three in the right proportions.
Alongside macronutrients, plants also need smaller amounts of micronutrients such as calcium, magnesium, and iron. Even though they’re required in smaller quantities, these trace elements are just as important for healthy, vigorous plants.
Why Fertiliser Matters in Hydroponics
In a soil garden, plants can draw nutrients naturally from the ground. In hydroponics, however, the plants rely entirely on the fertiliser you provide through the water system. This makes it both simpler and more precise:
- Consistent nutrition – Every plant gets the same amount of nutrients, reducing uneven growth.
- Faster growth – Because nutrients are delivered directly to the roots, plants can absorb them more efficiently.
- Bigger yields – Healthy plants with the right balance of nutrients produce more leaves, fruit, or flowers.
Choosing the Right Fertiliser for Your Tower
For Kiwi growers using a MyGreens hydroponic tower outdoors, the fertiliser you choose should be water-soluble and designed for hydroponic use. Regular garden fertiliser isn’t suitable because it’s not formulated to dissolve cleanly into water, and it can clog your system.
Instead, look for a hydroponic fertiliser that includes:
- A good balance of NPK
- Essential micronutrients
- Easy mixing instructions for use with water
This ensures your plants get everything they need without any extra fuss.
Tips for Using Fertiliser in Your Hydroponic Garden
- Follow the instructions – More fertiliser doesn’t mean better growth. Too much can actually harm plants.
- Check your water – In some parts of New Zealand, tap water is softer or harder than others. If you notice issues, you may need to adjust slightly.
- Observe your plants – Yellowing leaves, slow growth, or pale colouring can be signs your plants need more nutrients. Lush, vibrant growth usually means the balance is just right.
Keeping it Local
At MyGreens, we design our hydroponic towers for outdoor growing in New Zealand conditions. We don’t use grow tents or grow lights, and we only supply within New Zealand. Our systems work with natural sunlight, and with the right fertiliser, they provide a simple and sustainable way to grow fresh produce at home.
Final Thoughts
Plant fertiliser is the backbone of a successful hydroponic garden. By providing your plants with the right nutrients in the right amounts, you’ll enjoy faster growth, stronger plants, and tastier harvests. With a MyGreens hydroponic tower and a good fertiliser, growing your own food has never been more rewarding for Kiwi households.