How Often Should You Add Nutrients To Hydroponics

by Lettuce Be | Last Updated:

When you’re getting started with hydroponics or want your plants to be healthy, you must take care of their water systems. Ensuring you have the proper nutrients, pH level, and clean water is a big part of that. For a hydroponic garden, how often do you change the water? It is generally recommended that hydroponic water be changed every two or three weeks. To maintain optimal pH and nutrient levels, you may often need to change it more or less, depending on your system.

Changing your hydroponic water frequently, as well as how, is essential. Water changes occur in a more complicated manner than just dumping and replenishing the water every week.

It All Depends on Your Hydroponic System

adding hydroponic nutrientsThe specifics of your setup will also impact how often you need to change your hydroponic water. Due to evaporation and plant use, your water reservoir will lose some water volume. With a lot of light and heat, you’ll notice a loss of water due to evaporation. In addition, your reservoir could explode if there is insufficient coverage on it or if it is situated in direct sunlight or near sources of heat. If your plants use lots of water or are densely packed, you will lose water more quickly. Adding water frequently is necessary for plants like irises, lettuce, and spinach.

Fresh water must be topped up more frequently in smaller water reservoirs than in larger ones. Water has to be added to your hydroponics between water changes in the majority of cases. Water loss is quite common, so plan on topping up the water multiple times per day. Plan on adding water every few days if you don’t notice much difference in the water level. You will need to replenish the water every two to three weeks. Once you become familiar with your hydroponic system, you will be able to establish a schedule for topping up gallons of water and performing partial water changes.

Changing Your Hydroponic Water

There are two ways to change your hydroponic water. To properly replace water, it’s essential to use both methods. Later on, we’ll talk more about the reasons for this, but for now, you need to know what the two methods are and how to implement them.

First, you need to top off your water reservoir. It is essential to top off the water when you notice it getting low. Use clean, pH-balanced water to achieve this. Adding water at least several times per week, if not daily, is necessary. Be sure that you measure the water that you add when you top off the reservoir. Your logs will be necessary later to determine how often to change the water.

Changing the water less frequently and replacing a larger volume of water is the second method. You’ll need to perform a more extensive water change once your logs show that you have added half your reservoir volume through top-ups.

Fill the tank with fresh water by draining or emptying 50% of the total volume. A more considerable water change may be necessary every two weeks for most hydroponic systems, while a smaller reservoir may need it every week to ten days.

Manage pH and nutrients

The importance of tap water changes lies partly in maintaining your pH level and making sure your plants receive enough nutrients. The pH of your water will change with time. If the pH of your irrigation water isn’t in an acceptable range for optimal plant health, the nutrient mix you add won’t be able to reach them. You can read our complete guide on how to check pH here if you are unsure.

The only option for your plants is to change the entire water. The first reason is that other compounds, such as ammonia or nitrites, can accumulate to levels that eventually kill your plants. A stagnant reservoir can become a breeding ground for bacteria and fungi without an infusion of fresh water. A combination of chemical damage to roots and that creates the perfect environment for root rot to thrive. We have come up with a guide to help you prevent and treat root rot if you are unsure how to do it.

To avoid overstressing your plants, it is more important to perform regular water changes instead of a single and infrequent water change to maintain pH. In addition to biweekly water changes, you can keep the pH level stable by regularly adding clean water. Changing water conditions suddenly and dramatically (such as when it’s completely replaced) can do more harm to plants than good.

Control Saturation Of Nutrients

Changing the water when adding plant nutrients is helpful, but they also help prevent oversaturation of minerals, which can damage plants. Hydroponic plants use nutrients, but some minerals and compounds are left behind. The volume of water used by plants exceeds the nutrient ratio consumed by plants, which results in more saturated nutrients than when they began. Plant roots can be burned or damaged as a result of too many trace minerals. Test your nutrient levels if you’re not sure whether they’re helping or harming.

Determining Water Changes

The frequency of water changes may be different than you would usually expect under certain circumstances. Water change routines are typically changed in response to undesirable environmental conditions. By performing regular testing, you can identify problems in your reservoir before they cause severe damage.

Different types of testing

To ensure your hydroponic water is maintained correctly, you need to be familiar with two main types of water testing. You can test the water for other things more in-depth, but pH and EC are sufficient for most hydroponic gardeners.

pH testing

pH tests are used to measure the pH level, or potential hydrogen content, of your nutrient water. A pH level of 5.5 to 6.5 is ideal for most plants. There is a slight fluctuation between water cycles, but it should not change drastically. Unless your plants show signs of wilting, illness, damage or discoloration, you should test your pH every three or four days. There are two types of pH test kits available: paper strips and liquid solutions. Due to their convenience and accuracy, digital pH testing pens are now being used more frequently.

EC testing

Electrical conductivity testing, also known as EC testing, allows you to monitor and maintain the strength of your hydroponic nutrient solution. Plants typically flourish at EC levels between 1.2 and 2.0, depending on the crop that you’re growing. In case your water EC is lower than that, you should add more nutrients. Similarly, if your EC level is too high, you need to dilute it with clean water. If the water level is at an extreme, it may be necessary to remove some of it and replace it with fresh water over several days. Some people use a digital pen to test for both EC and pH levels. Until they’re comfortable with their water, they test daily. At least three times a week (once you test your pH) and whenever you add a hydroponic solution is needed. If you aren’t sure how to test the EC in water, we have a detailed guide.

Related Questions

How frequently should I clean my water reservoir?

It may vary depending on how your setup is configured. The smaller the gallon reservoir, the more frequently you must clean it. As a rule of thumb, you must clean out your tank once the water you are replacing or topping up with equals your total tank capacity.

Does my hydroponics system require additional aeration?

Hydroponic setup does not always require the use of an air pump or stone. If your plants’ roots are entirely submerged, oxygenating the plain water is a good idea. Additionally, this prevents plants from “drowning” without oxygen and helps limit fungi, algae, and bacterial growth.