Understanding Hydroponic Nutrients
Nutrients are often the part of hydroponics that makes people pause. Bottles, measurements, pH, nutrient strength — it can sound like a lot at first. But once you understand the basic rhythm, feeding your tower becomes much more manageable.
In a traditional garden, plants draw nutrients from the soil. In a hydroponic system, those nutrients are delivered through the water instead.
That is what FlowGrow nutrients are doing. They provide the essential minerals your plants need to grow, while the tower keeps water moving through the system so roots can access water, nutrients, and oxygen.
Hydroponic nutrients provide the minerals plants would usually draw from soil.
The nutrient water moves through the tower, helping roots access what they need as they grow.
The short version: hydroponic nutrients are plant food mixed into water. You do not need to memorise every mineral to grow successfully at home.
What do hydroponic nutrients actually do?
Plants need nutrients to support root growth, leaf growth, stem strength, flowering, and fruiting. In soil, these nutrients come from the ground. In hydroponics, they come from a carefully balanced nutrient solution.
FlowGrow nutrients are designed to be straightforward and repeatable for home growers. The aim is not to turn growing into a science project. It is to give your plants a steady, balanced feed that supports healthy growth in real home conditions.
Helpful to know
You do not need to understand every ingredient to get started. What matters most is mixing correctly, using equal parts A and B, keeping water topped up, and refreshing your reservoir when needed.
Why are there two bottles, A and B?
FlowGrow uses a two-part nutrient system. This means the nutrients come in two bottles: Part A and Part B.
This is not to make things harder. Some nutrients need to be kept separate in concentrated form so they stay stable and available for your plants. If everything was combined into one strong concentrate, some elements could bind together and become less useful.
Add to water first
Add Part A to your reservoir water, then mix gently before adding Part B.
Add separately
Add Part B after Part A has been diluted into the water. Never mix concentrates together directly.
Important: always add nutrients to water. Never mix concentrated Part A and Part B together before adding them to your reservoir.
How much nutrient do you actually use?
For FlowGrow, feeding guidance is based on the recommended 15-litre working reservoir.
Most home growers do not need a complicated crop-by-crop feeding chart. The main thing is knowing when to use the normal tower mix, when to start gently, and when Bloom nutrients become useful for flowering or fruiting plants.
| Use | Part A | Part B | Helpful to know |
|---|---|---|---|
| For very young plants | 40 ml | 40 ml | A gentle starting mix while young plants settle in and begin growing. |
| Everyday tower growing | 75 ml | 75 ml | For most purchased seedlings, leafy greens, herbs, young established plants, and everyday tower growing. |
| Bloom heavier fruiting option | 105 ml | 105 ml | For mature flowering or fruiting plants that are growing strongly and receiving good light. |
The everyday tower mix is the main mix most growers will use. The 40 ml mix is there for very young plants while they settle in, not as a long-term rule for every plant.
For a step-by-step dosing guide, read the FlowGrow Feeding Guide.
Grow nutrients vs Bloom nutrients
Different plants need different support as they grow. Leafy greens and herbs mainly focus on leaves, stems, and roots. Fruiting plants eventually shift energy into flowers, buds, and fruit.
For leafy growth
Grow nutrients are used for purchased seedlings, leafy greens, herbs, young plants, and early plant growth. They support root development, stems, and fresh leaf growth.
View Grow Nutrients
For flowering and fruiting
Bloom nutrients are used when plants begin to flower, form buds, or fruit. This can include strawberries, compact tomatoes, and chillies.
View Bloom NutrientsMany home growers start with leafy greens and herbs first, then experiment with fruiting plants as their confidence grows.
How to use Grow nutrients
Grow is the nutrient most home growers will use for everyday tower growing, especially when starting with garden centre seedlings, lettuce, herbs, and leafy greens.
For most Grow use
Mix 75 ml Grow A + 75 ml Grow B into 15 L of water.
For very young plants, start with 40 ml Grow A + 40 ml Grow B in 15 L first. Once plants look settled and growth strengthens, move to the normal tower mix.
How to use Bloom nutrients
Bloom is used once plants begin forming buds, flowers, or fruit. It is not needed for leafy greens and herbs that are being grown mainly for leaves.
For standard Bloom feeding
Mix 75 ml Bloom A + 75 ml Bloom B into 15 L of water.
For mature fruiting plants that are growing strongly and receiving good light, you can increase to 105 ml Bloom A + 105 ml Bloom B in 15 L. This is best treated as an optional heavier fruiting mix, not a starting point for young plants.
What happens as water levels drop?
As your plants grow, they use water and absorb nutrients. But they do not always use both at exactly the same rate.
This means that as the water level drops, the nutrient strength in the reservoir can slowly change. In warm weather or during faster growth, water may also disappear more quickly.
This is normal in a recirculating system. The easiest habit is to check your water level regularly, top up when needed, and refresh the reservoir every few weeks depending on plant size, water use, and growing conditions.
Helpful rhythm: top up water regularly, check how your plants look, and refresh your reservoir when the system needs a clean reset.
What is EC?
EC stands for electrical conductivity. In plain terms, EC is a way of measuring how strong your nutrient water is.
A lower EC means a gentler nutrient mix. A higher EC means the water contains more dissolved nutrient.
The FlowGrow dosing system has been designed around real home use and practical EC testing. The normal Grow mix of 75 ml Part A + 75 ml Part B in 15 L has measured around EC 1.0 to 1.1 in FlowGrow testing, although your own reading can vary depending on water quality, temperature, meter type, and growing conditions.
You do not need to chase EC numbers to get started. For most FlowGrow growers, following the ml guide is enough. An EC meter can simply help you learn what is happening in the reservoir as your confidence grows.
If you want to understand EC more clearly, read our guide to pH and EC for home hydroponic growing.
Stability matters more than perfection
You do not need to measure constantly or chase exact numbers every day. For most home growers, steady conditions are more helpful than constant adjusting.
Good light, regular water top-ups, balanced nutrients, and observation will tell you far more than trying to perfect every reading.
When an EC meter can help
You do not need an EC meter to get started with FlowGrow. But as your plants grow, or if you want a clearer picture of what is happening in your reservoir, an EC meter can be useful.
- It can help you check nutrient strength.
- It can show changes as water levels drop.
- It can support small, confident adjustments over time.
It is best seen as a helpful learning tool, not something that needs to make growing feel complicated.
You can explore testing options in our Helpful Growing Extras.
What about pH?
pH is about how easily your plants can access nutrients in the water.
Most home hydroponic vegetables and herbs grow well when the nutrient water sits somewhere around pH 5.5 to 6.5.
If pH moves too far outside this range, nutrients may still be in the water, but your plants may struggle to absorb them properly.
How to keep pH manageable
Use pH strips or a digital meter to check occasionally. If you need to adjust, make small gradual changes rather than trying to force a perfect number.
A small note on light
Nutrients are only one part of growing well. Light still matters.
Leafy greens and herbs are usually more forgiving, especially in bright indoor spaces or sheltered outdoor positions. Fruiting plants such as strawberries, chillies, and compact tomatoes generally need stronger light to flower and fruit well.
If a plant is in weak light, adding stronger nutrient will not automatically make it grow faster. Good light, steady water, and balanced feeding work together.
A small note on water temperature
Water temperature can make a difference over time, especially during warmer months.
Plants generally do best when the reservoir water stays cool to slightly room temperature. If water becomes too warm, it can hold less oxygen, which may make it harder for roots to stay healthy.
You do not need to manage this closely. Keeping your reservoir out of harsh direct heat and placing your tower in a suitable growing position is enough.
Reading your plants
Your plants will usually give you clues about how things are going.
- Pale leaves can sometimes mean plants need more nutrients, better light, or a reservoir refresh.
- Brown leaf tips can sometimes mean the nutrient mix is a bit strong.
- Slow growth can be linked to light, temperature, young roots, transplant adjustment, or nutrient balance.
You do not need to react instantly to every small change. Observe first, then make adjustments one step at a time.
Keeping nutrients manageable
You do not need to understand every nutrient detail to grow successfully at home.
You just need to:
- use equal parts A and B
- add nutrients to water, not directly together
- use the normal tower mix for most everyday growing
- start gently for very young plants
- switch to Bloom when plants begin flowering or fruiting
- keep water topped up
- refresh the reservoir when needed
- check in on your plants regularly
Over time, this becomes part of the rhythm of growing. Instead of wondering if you are doing it right, you begin to understand what your plants need.
Frequently asked questions
Do I need to change nutrients every week?
No. You do not need to fully change nutrients every week. Top up water as needed and refresh the reservoir every few weeks depending on plant size, water use, and growing conditions.
What is the normal FlowGrow tower mix?
For most everyday tower growing, use 75 ml Part A and 75 ml Part B in a 15 L reservoir.
When should I use the gentle mix?
Use 40 ml Part A and 40 ml Part B in 15 L for very young plants while they settle in and begin growing.
What happens if I add too much nutrient?
Plants may show stress such as brown leaf tips, curling leaves, or slower growth. If you think the mix is too strong, refresh the reservoir with clean water and restart with a gentler dose.
Do I need an EC meter to grow successfully?
No. You can get started without an EC meter by following the FlowGrow feeding guide. An EC meter can be helpful as your confidence grows because it shows how strong your nutrient water is.
What is the difference between Grow and Bloom nutrients?
Grow nutrients support leafy greens, herbs, young plants, and early growth. Bloom nutrients support flowering and fruiting plants such as strawberries, compact tomatoes, and chillies.
How much Bloom nutrient should I use?
Use 75 ml Bloom A and 75 ml Bloom B in a 15 L reservoir as the standard Bloom mix. For mature fruiting plants growing strongly in good light, you can increase to 105 ml Bloom A and 105 ml Bloom B.
Why are my leaves turning yellow?
Yellowing leaves can happen for several reasons, including low light, nutrient imbalance, pH sitting outside the helpful range, the plant adjusting after planting, or the reservoir needing a refresh. Start with the simple checks first.
Helpful next steps
Once nutrients start to make sense, home hydroponic growing feels much more manageable. These guides and products can help you keep learning at your own pace.
Read the Feeding Guide
Learn the updated FlowGrow feeding rhythm: very young plants, everyday tower growing, and Bloom support for fruiting plants.
Understand pH and EC
Learn what pH and EC mean, why they matter, and how to keep home growing steady.
What can you grow?
Explore the herbs, leafy greens, and fruiting plants that suit home hydroponic towers.
Ready to keep growing?
FlowGrow nutrients are designed to make feeding your tower straightforward, balanced, and manageable at home.
