As a hydroponic gardener, my main job is to make sure that I am providing my veggies and herbs with the best nutrients. Two years back, I was faced with this question: Do hydroponic nutrients expire? Speaking through experience, I am confident that I can absolutely answer this question now.
Generally, hydroponic nutrients—dry or liquid—do not easily expire. They can last for years. However, three factors can shorten their shelf-life: 1) heat, 2) moisture, and 3) air exposure. Storing in a cool cabinet, using air-tight containers, and providing ventilation are ways to make hydroponic nutrients last.
So, what is the best location? Do containers matter? How to control hot temperature during storage? These are just some of the questions that will be answered for you today! So let us dive in.
Hydroponic nutrients, generally, do not expire. However, if not properly stored their quality will degrade significantly leading to a lower harvest than a properly stored nutrient would have done.
Most hydroponic nutrients are composed of minerals and elements which are not prone to breaking down.
For instance, nitrogen, a major component of hydroponic nutrients, is a hard element to break down. Since it is made up of 2 atoms of nitrogen closely bonded together, it would require a high temperature to disintegrate.
Although hydroponic nutrients do not expire, there are factors that cause degradation to their quality, rendering them less effective.
With that, I think it is better for us to know the other factors that affect hydroponic nutrient shelf-life and quality.
Growing up near a farm, I have witnessed several fertilizer deliveries in our house. The first thing we always do before this bunch of fertilizer sacks comes is to prepare our garage or empty a room.
You might ask, why?
Well, the absence of direct sunlight exposure is the common factor between these two places. This initial step is essential because heat can degrade the quality of dry nutrients.
Furthermore, nutrients such as ammonium nitrate and potassium nitrate can explode under direct sunlight. So, if you are using these fertilizers in your hydroponic system, make sure to store them in cool places!
Dry hydroponic nutrients will absorb moisture. This can lead to nutrient loss, clumping, and/or degradation.
Moisture can be a real enemy in storing dry hydroponic nutrients. One of the major aftermaths of moisture absorption is caking.
In simple words, caking refers to when nutrient granules clump together, forming a huge chunk of fertilizer. Although they can still be used, nutrient loss may happen along the process.
Moreover, degradation happens when the dry hydroponic nutrients absorb water from the air.
When dry hydroponic nutrients are exposed to air, they can absorb humidity that will further result in degradation and caking. Meanwhile, liquid nutrients will evaporate once exposed to air for a long time.
As mentioned earlier, granular dry nutrients can absorb moisture from the air. When this happens, the moisture will cause liquidation of each granule. When these nutrient granules melt, they would clump with the granules around them—leading to caking.
In the case of liquid hydroponic nutrients, exposing them to air will lead to volatilization. This means that your desired nutrient might escape from your solution by transforming into its gas form.
A good example of this is any ammonium-based nutrient fertilizer. Studies have confirmed the volatilization of ammonia to its gas form due to exposure to air and high temperature.
So to avoid this, make sure that the lids of your hydroponic nutrients are always capped.
Hydroponic nutrients should be stored in a place where ideally heat, moisture, and air exposure should be under control. This means that one needs to take into account the 6 factors for proper hydroponic nutrient storage: 1) location, 2) container, 3) label, 4) ventilation, 5) temperature control, and 6) spill prevention.
When storing large quantities of hydroponic nutrients, the location must not have a direct entry of sunlight. For household hydroponic gardening, a cool, dark cabinet away from any sources of water will do.
Air-tight containers are the best option in storing dry hydroponic nutrients.
Since air exposure may lead to nutrient degradation for dry fertilizers, make sure that you are using sealed containers like this that you can buy on Amazon.
Most of the dry nutrients come in their own packaging. Thus, when you opt to buy air-tight containers, you still need to put the whole fertilizer package inside the container. Do not pour the nutrient granules into the container. This way, you can secure them properly from heat, moisture, and air.
Putting labels on hydroponic nutrient containers will ensure that one is using their desired fertilizer, in the desired amount.
Another aspect that we somehow neglect is placing labels.
This is vital, especially for those who grow plants on a large scale. In a storage room or cabinet, some nutrients may be misplaced. When this happens, there are chances that you might be providing the wrong fertilizer to your plants, in the wrong amounts!
In large fertilizer storage rooms, ventilation must always be a priority.
This is relevant for those storing bulk nutrients. There has been a case of the explosion of ammonium nitrate, specifically in Beirut, Lebanon. Exposure to air and high temperature were the considered reasons for the explosion.
Oxygen is needed for combustion to happen. Thus, it is possible that there has been fertilizer exposed to air.
Furthermore, ammonium nitrate degrades on its own when exposed to hot temperatures. During this reaction, nitrogen oxides and water vapor are released, thereby causing explosions.
A cool cabinet without direct heat and light exposure will suffice for household hydroponic gardening.
We have discussed a while back that the consequence of heat is degradation. Thus, you need to make sure that there are no direct sources of heat near your hydroponic nutrients storage area.
This means no furnaces, no steam pipes, and of course, no sunny windows!
Cleaning materials such as cloth and mop for liquid nutrients; and broom and dustpan for solid nutrients must always be present near the storage area.
This step is a precaution for damaged containers, spills during the transfer of nutrients, and accidental outpours during nutrient measurement and package opening.
Empty containers of nutrient fertilizers need to be discarded after usage, based on environmental protection authorities.
These containers may cause chemical leakage that can be harmful to the environment. Here are some steps in the proper disposal of fertilizer containers.
- Check if the product has a “DANGER-CORROSIVE” label. These products must not be poured down the drain.
- Dry the containers using newspaper or any absorbent material.
- Place the empty container in a double bag.
- Label it with “Danger – Not for Recycling”.
- Put it in the garbage bin.
If the container does not have a danger label, you can follow step 2 and recycle them along with other rigid plastic, glass, metal, and boxes.
How long should mixed hydroponic nutrients be used?
Hydroponic nutrients dissolved in water can sit for 7 to 10 days. However, it is advisable to use mixed nutrients immediately. If you let your hydroponic nutrient sit for a long time, it will cause degradation since it is exposed to heat and air.
Is it necessary to change hydroponic nutrients frequently?
In hydroponic gardening, the nutrient water must be changed often, usually every 1-3 weeks. This is necessary because your plants consume nutrients and water daily. Thus, the strength of your hydroponic nutrient solution decreases over time.
Which stores longer: dry or liquid hydroponic nutrients?
Dry hydroponic nutrients can last longer but should be stored in air-tight containers as they can absorb moisture from the air. Learn more about the difference in shelf-life of dry and liquid nutrients in our article on the 3 hydroponic nutrients you’ll need.
Hydroponic nutrients do not expire but it is important to control their exposure to 1) heat, 2) moisture, and 3) air, because these factors shorten shelf-life and decrease quality.
Heat, moisture, and air exposure can cause degradation, nutrient loss, and/or, caking. Hydroponic nutrients must be stored in a place with cool temperature, packed in air-tight containers, marked with labels, and prepared in case there will be spillage.
Empty fertilizer containers must be dried out, double bagged, labeled with “not for recycling”, and placed in the garbage if it is corrosive. It can be recycled, if it is not corrosive.
- “A Cheap Way to Chop Up Nitrogen” by Torrice, M. in Science
- “Factors Affecting Nitrogen Fertilizer Volatilization” by Jones, C. et al. in Montana State University Extension
- “Fertilizer Storage and Handling” by UMass Extension Greenhouse Crops & Floriculture Program in University of Massachusetts Amherst
- “Safe Handling and Disposal of Harmful Products” by New York City Government in NYC Government
- “What is Ammonium Nitrate, the Chemical That Exploded in Beirut?” by de Silva G. in Scientific American