A good base nutrient is the foundation of a balanced feeding program. But when a particular nutrient is in short supply, a targeted supplement may help correct the imbalance.
Growth Technology’s GT Liquid Range includes products supplying iron, nitrogen, trace elements, and a combination of calcium, magnesium and nitrogen.
These products serve different purposes. Choosing the right one starts with understanding what your plants need, rather than adding several supplements just in case.
Before You Choose a Supplement
Yellow leaves, weak growth and damaged leaf tips can suggest nutrient problems, but symptoms alone don’t confirm a deficiency.
Incorrect pH, unsuitable watering, unhealthy roots and nutrient imbalances can affect uptake even when nutrients are present. Before adding a supplement, check your growing conditions and review what your base fertiliser already supplies. For persistent problems, water, growing-media or plant-tissue testing can help narrow down the cause.
Rainwater and reverse-osmosis (RO) water contain fewer background minerals than many other water sources, but this does not automatically mean extra supplements are needed. Your base nutrient may already supply the required elements.
GT Liquid Range at a Glance
| Product | What it supplies | When to consider it |
|---|---|---|
| GT Liquid Iron | Iron | When an iron shortage has been identified |
| GT Liquid Nitrogen | Nitrogen | When nitrogen supply is inadequate for healthy growth |
| GT Liquid Trace Elements | Iron, manganese, zinc, boron, copper and molybdenum | When one or more trace elements are lacking |
| GT Liquid Cal Mag Nit | Calcium, magnesium and nitrogen | When additional supplies of these nutrients are needed |
GT Liquid Iron
Iron is essential for chlorophyll formation and several processes involved in plant growth.
Iron deficiency commonly appears as yellowing between the veins of young leaves, while the veins remain greener. However, similar symptoms can have other causes, so check growing conditions before treating them as proof of an iron shortage.
GT Liquid Iron provides a targeted iron supplement rather than a broader trace-element mix.
When to Consider It
When iron supply is inadequate, or when an iron-related problem has been identified after checking pH, root health and the existing nutrient program.
Application Guide
The manufacturer currently lists:
- Hydroponics and potting mix: 1–2 mL per litre of water.
- Foliar feeding: 1 mL per litre of water, sprayed in low-light conditions.
Follow the current bottle label for application frequency and any product-specific precautions. Do not increase the dose simply because leaves have not changed colour immediately.
GT Liquid Nitrogen
Nitrogen supports leafy growth, chlorophyll production and plant development.
A nitrogen shortage often causes older, lower leaves to become pale or yellow, alongside reduced growth and vigour. This pattern can help distinguish it from an iron-related problem, which commonly affects younger growth first.
GT Liquid Nitrogen is a targeted option when the existing feeding program does not provide enough nitrogen.
When to Consider It
When nitrogen supply is inadequate for the crop and its growth stage. Extra nitrogen is not always beneficial: excessive application can encourage leafy growth at the expense of timely fruiting.
Application Guide
The manufacturer currently lists:
- Hydroponics and potting mix: 1–2 mL per litre of water.
- Foliar feeding: 1 mL per litre of water, sprayed in low-light conditions.
Follow the current bottle label for frequency, and account for the nitrogen already supplied by your base nutrient and other additives.
GT Liquid Trace Elements
Plants require trace elements in small quantities, but these nutrients still play essential roles in healthy growth.
GT Liquid Trace Elements supplies iron, manganese, zinc, boron, copper and molybdenum. It offers a broader range of micronutrients than GT Liquid Iron.
When to Consider It
When a trace-element shortage has been identified, or when an assessment of your water and feeding program indicates that additional micronutrients are needed.
Low-mineral water may be one factor to consider, but using RO water or rainwater is not, by itself, a reason to add a trace-element supplement. Check whether your base fertiliser already supplies a complete micronutrient package.
Application Guide
The manufacturer currently lists:
- Hydroponics and potting mix: 1–2 mL per litre of water.
- Foliar feeding: 1 mL per litre of water, sprayed in low-light conditions.
Follow the current bottle label for frequency. Avoid combining multiple micronutrient supplements without accounting for overlapping ingredients.
GT Liquid Cal Mag Nit
GT Liquid Cal Mag Nit supplies three nutrients in one supplement:
- Calcium: 4% w/v.
- Magnesium: 2% w/v.
- Nitrogen: 5% w/v.
Calcium supports plant structure, magnesium is a component of chlorophyll, and nitrogen supports growth.
Unlike a calcium-only or magnesium-only product, Cal Mag Nit adds all three nutrients together. That makes it important to consider the whole feeding program before using it.
When to Consider It
When additional calcium, magnesium and nitrogen are appropriate for your crop, water source and base nutrient.
Soft water and RO water can make background calcium and magnesium supply worth checking, but supplementation should be based on what the complete nutrient program provides.
What About Blossom-End Rot?
Blossom-end rot in tomatoes and similar crops involves insufficient calcium reaching developing fruit. It does not necessarily mean the growing medium lacks calcium.
Uneven watering, root damage and other conditions can interfere with calcium uptake and movement. Adding a calcium-containing supplement may help where supply is inadequate, but it is not a guaranteed remedy. Review watering and root conditions as well as nutrition.
Application Guide
The manufacturer currently lists:
- Hydroponics and potting mix: 1–2 mL per litre of water.
- Foliar feeding: 1 mL per litre of water, sprayed in low-light conditions.
Follow the current bottle label for frequency and remember that this supplement also increases nitrogen supply.
A Note for Aquaponic Growers
Aquaponic systems need separate consideration because fish and biological filtration are part of the system.
Do not assume that the hydroponic or potting-mix rates above are appropriate for an aquaponic reservoir. Confirm product suitability and system-specific dosing with the manufacturer or a qualified aquaponics adviser before use.
Which GT Liquid Product Should You Choose?
Choose according to the nutrient shortage you are trying to address.
GT Liquid Iron provides targeted iron supplementation. GT Liquid Nitrogen adds nitrogen. GT Liquid Trace Elements supplies a broader micronutrient mix. GT Liquid Cal Mag Nit adds calcium, magnesium and nitrogen together.
You do not need to use the whole range. Start with a balanced base nutrient, identify the likely cause of the problem, and select a supplement only where it fills a genuine gap.
If you are unsure which option fits your setup, contact Hydroponic Solutions with details of your plants, growing medium, water source and current nutrient program.
Further Reading
Manufacturer Product Information
- Growth Technology Liquid Iron
- Growth Technology Liquid Nitrogen
- Growth Technology Liquid Trace Elements
- Growth Technology Liquid CalMagNit