How Often Should You Add Nutrients to Hydroponics?

Hydroponics has gained immense popularity in the horticulture world where plants are grown without the involvement of soil. Instead, water and other essential nutrient solution are used to grow the plants.

The importance of nutrient solution in hydroponics is that it helps to provide the roots of plants with water, oxygen, and other indispensable mineral elements that are available in soluble form.

But do you know how often should you add nutrients to hydroponics?

Though there isn’t any fixed routine, but you should add nutrient solution every 7 to 10 days to the plants that you are growing hydroponically.

How Often Should You Add Nutrients to Hydroponics
How Often Should You Add Nutrients to Hydroponics?

The main ingredient of this nutrient solution is inorganic ions that are present in soluble salts of the important elements needed by the plant. These nutrients are mainly segregated into macronutrients and micronutrients, equally important for the growth and development of the plant. 

How often should you add nutrients to hydroponics? (The Best Guide)

Most gardeners that grow hydroponics plants often face the question of how often they should add nutrients to the hydroponic plants. There are a lot of factors that count on this as it depends on the growing method you are applying, the type of nutrients you are feeding to the plants, and also the growth stage of the plants they are currently in.

However, if you are using a hydroponic reservoir, you can remix the nutrient solution every 7 to 10 days. You must drain it properly, clean it, and remix the nutrient solution. Then just top off the reservoir with plain water.

Make sure you flush a small amount of the nutrient solution so that it won’t give the plant any unnecessary stress. But keep a close check on the temperature and pH of the flush water.

How often should you add nutrients to hydroponics (detail guilde)
How often should you add nutrients to hydroponics?

It is not recommended to over-flush the nutrient solution. Let us look into details about different hydroponic crops and their nutritional needs:

Leafy Greens

Growing leafy greens like lettuce and spinach through a hydroponic system is completely different from growing it in soil and is a rewarding process. The nutrients it needs to grow properly are calcium, potassium, and magnesium. Calcium is required to prevent the leaves from wilting and burning.

Nitrogen and phosphorous are required to fix any critical issue. The recommended amount of nitrogen is 5 NPK, phosphorous is 18 NPK, potassium is 38 NPK, calcium is 100-150 PPM, and magnesium is a quarter teaspoon. You should add this nutrient solution every once a week or once every two weeks. 


Growing herbs through a hydroponic system is quite effective and is different from growing them in soil. Herbs need regular and frequent fertilization when grown hydroponically rather than those grown in garden soil or potting mix.

Hence you need to add nutrients to the herbs grown every two weeks or as specified in the hydroponic system only with hydroponic fertilizer that can be applied to the herbs and vegetables.


It is observed that hydroponically grown basil is highly susceptible to magnesium deficiency because the water doesn’t have enough magnesium in it. The herbs turn to chlorotic yellow because of micronutrient deficiency. So a magnesium supplement combined with calcium is always added to the herbs.

However, one needs to keep in mind that you should not over-fertilize your herbs as that would lead to excess nitrogen resulting in slow growth of the herbs. The herbs lose nutrient solution over time, hence it is required to change the solution every two to three weeks. 


Growing flowers through a hydroponic system is way better than growing them in garden soil because of its quick results. You have complete control over the nutrients as well as the pH balance.

The hydroponic nutrients for flowers come in liquid or powder base and need to be added after every two weeks for the flowers to bloom properly.

Fruits and Vegetables

The nutrients required for growing fruits and vegetables through hydroponic gardening are nitrogen, potassium, phosphorous, calcium, and magnesium.

You need to mix these essential nutrients into the water every two weeks to ensure the complete growth of the fruits and vegetables. The best NPK ratio for hydroponic vegetables and fruits is 7-9-5. Depending on the crop’s stage, the nutrient concentration is added. 

How do you maintain nutrients in hydroponics?

In hydroponic gardening, it is important to add nutrients through the Hydroponic Nutrient Reservoir. So it is essential to maintain nutrients in the reservoir. 

  • Temperature Control: The temperature of the nutrient solution is very critical and if it is too high, then the oxygen level from the aerators goes down. It is advised to keep the nutrient solution between 65-75 degrees. 
  • Change of water: Keeping the water in the nutrient reservoir for a long time is not advised. You should change it every week or two weeks at max and add fresh nutrient solution to ensure full growth of the hydroponic plant. 
  • Use of EC meter: If you want to check the nutrient solution, then the EC meter is the best. It measures the amount of fertilizer inside the water, so when you change the nutrient solution completely, with the help of an EC meter, you will check the nutrients. 
  • Proper Aeration: If the roots of the hydroponic plants don’t get enough oxygen, they would drown and eventually rot. So proper aeration in the nutrient reservoir is very important. 
  • Addition of Filter: A hydroponic system filter always helps prevent plant matter and debris from getting inside the nutrient reservoir. But it is also important to clean the filter to remove the pesky build-up. 
  • A regular check of pH: The most important point to maintain nutrients in hydroponics is to check the pH level regularly. The ideal pH should be maintained is in between 5.5-6.5. 

Tips for monitoring nutrient levels in Hydroponics

Certain steps need to be followed to monitor the nutrient levels in hydroponics. 

Tips for monitoring nutrient levels in Hydroponics
Tips for monitoring nutrient levels in Hydroponics
  • Regularly testing pH and EC levels: If you are into hydroponic gardening, maintaining the pH and EC levels is very important. The plant’s health depends a lot on these levels while adding nutrient solution. The ideal pH level is 5.5-6.5. The EC level depends on the variety of plants grown in the hydroponic garden, and you need to check it properly. 
  • Checking for signs of nutrient deficiencies or toxicity: When you are into hydroponics gardening, you need to have proper knowledge of the plants you are growing along with their deficiencies and how to identify them. Trust me, most of your issue is solved if you correctly understand the current issue of your plant. Then, based on the deficiency, you need to add a nutrient solution. 
  • Keeping detailed records of nutrient additions and plant growth: If you add nutrient solution to your hydroponic plants just to add it, then you are creating havoc for your plants. It is very important to keep a record of the added nutrient solution so that there should not be excess or deficiency of any particular nutrient. Further, it is also mandatory to keep track of the plant’s growth rate because the nutrient levels depend on the plant’s growth stage. 

How long do hydroponic nutrients last?

It is important to provide the best nutrients to your hydroponic plants for their best growth and development. The shelf life of hydroponic nutrients lasts quite a long in a liquid or dry state. However, if they are exposed to heat, moisture, and air exposure, then their shelf life is affected.

How long do hydroponic nutrients last
How long do hydroponic nutrients last?

So it is always advised to store them in a cool place inside air-tight containers and provide proper ventilation. This way you can ensure the quality of the nutrients you are using. 

Once these hydroponic nutrients are dissolved in water and added to the plants, they last for 7 to 10 days. At maximum, it remains for 3 weeks. So after this period, you need to drain the water, clean it, and add fresh nutrient solution to the plants to ensure maximum benefit from the nutrients. 

Frequently Asked Questions (FAQs)

Can you use Miracle Grow in a hydroponic setup?

Miracle Grow is one of the most renowned fertilizers used for gardening however they are not the ideal one for hydroponics. You can use it in your hydroponic setup however, it is not the best one to recommend.

Because some of the Miracle Grow fertilizers didn’t mix well enough or have all the necessary nutrients, it is not much recommended. Still, if you use it, you should never use the traditional types.

How often should hydroponic water be changed?

It is important to change the hydroponic water every 7 to 10 days. Because the nutrients added to it lose their strength slowly and if the water is kept stagnant in it for a long time, it will affect the plant’s growth. Hence, it is always advised to drain the water, clean it, and add fresh nutrient solution to the water in the hydroponic system.

Should I use nutrients every time I water?

No, you need not add nutrients every time you water the hydroponic plants. The nutrients should be added based on the stage of the plants every 7 to 10 days or a maximum of three weeks. However, you need to water the hydroponic plants 1-15 watering per day. 


Hydroponic gardening is a great setup to grow your plants without the involvement of soil in it. However, to maintain this, certain steps need to be followed to ensure the optimum growth of the hydroponic plants.

Further, it is also important to add nutrient solutions to the plants so that plants can have healthy growth and help them recover from any health issues.

So it is very important to know the symptoms of plant diseases and identify them and provide the necessary treatment to save the plant. Hope this article will help you know in detail about the nutrient solution that needs to be added to the hydroponic plants. 

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