Hydroponic Care: Why Flushing is Necessary for Your System

If you’re an amateur grower looking to start your own hydroponic system, the concept of flushing might not be very familiar to you. This is the process of removing old nutrient solution and replacing it with plain water or a new batch of hydroponic plant enhancer. 

Doing so is necessary for hydroponic systems because without a growing medium like soil to break down excess material, the buildup of these can negatively impact your plants’ health. Aside from that, flushing does carry with it some benefits for your hydroponic plants. 

To emphasise its importance, here are three benefits of flushing your hydroponic system regularly:

1. System Cleanliness 

Flushing your system is about the only way to keep your hydroponics system clean. If you don’t flush your system in regular intervals, bacteria, algae, or any pathogen can grow and quickly ruin your crops as soon as they set in.

Getting rid of dead plant matter and spoiled water, as well as the cleaning of intake filters, are essential to prevent bacterial growth. Once these potentially harmful sources are cleaned up, you should replace the discarded solution with a new batch of plant nutrient enhancer to keep your beloved plants growing healthy.

2. Getting Rid of Excess Mineral Buildup

Hydroponic growers need to flush their systems to get rid of salts and other minerals from the system. If left untended, the resulting buildup can hamper osmosis—the process used by plants to absorb water through their roots. 

Direct contact with salt can also damage a plant and disrupt the careful balance of nutrients in a system. An excessive buildup of salt is common with systems using growing media with porous surfaces, such as Rockwool and an ebb-and-flow system. 

The earliest sign of salt buildup is white crusting on the growing media, the conduits, and eventually, the plant base. 

3. Better Yield 

If you’re flushing for a better yield, you should pay close attention to the particular frequency that you do so in your hydroponic plant system. As mentioned above, the buildup of salt and other minerals are not beneficial to plants, especially if you are close to the harvesting season. 

Flushing before the harvest season ensures that your plants use the nutrients already in their systems and are not wasting energy trying to absorb the nutrients fed through your medium. Aside from possibly ending up with an unhealthy plant, unflushed minerals can end up affecting the chemical makeup of the yield, interfering with its overall taste and aromatic properties. 

When should I flush my hydroponic system? 

As with other kinds of agriculture endeavours, the key is to get your water’s pH levels at a slightly acidic state, which amounts to pH5.8-6.0. 

But the timing matters as well, as flushing nutrients from a growing plant can also lead to malnutrition or death—so watch out for that! The best time to flush is one week before harvest when plant growth has stabilised, and fruit production has taken priority. 

To flush your system, remove the old solution from the reservoir, and replace ith with slightly acidic plain water. The plants should sit in this water for a minimum of seven days until harvest. 


Hydroponic plants are advantageous if you’re aiming for faster production since it allows you to yield more crops in a smaller surface area within a shorter time span.  However, this approach also necessitates very particular routine agricultural maintenance procedures, such as flushing. Through regular monitoring of pH levels and salt levels, and consistent flushing when the need arises, your setup should yield bigger and healthier crops. 

Are you looking for the best plant enhancers in the UK for your hydroponic garden? Moonshine Global aims to provide better plant nutrition for hydroponic plant growers in the UK. We sell everything, from root enhancer to Moonshine foliar sprays, to keep your hydroponic garden healthy. Browse our shop today and find the products best suited for you.