Growing cannabis in Flood and Drain system

Growing cannabis in Flood and Drain system

The flood and drain system is simpler than you can imagine. Cannabis plant is put into a bucket or on a table, its roots are periodically flooded by nutrient solution from the nearby reservoir. When the pump stops, the solution drains back into the reservoir. There is a timer that regulates the frequency of the flood and drain cycles.

Marijuana takes all the needed nutrients from the solution. Usually the flood frequency is increased when cannabis plant grows bigger. Every environment for growing plants is different in terms of humidity, temperature and airflow, so experienced growers often adjust the amount of nutrient solution, the number of floods per day and the length of each flood to get the maximum yield of cannabis.

What are the advantages of growing cannabis in Flood and Drain system?

  • The efficiency of flood and drain is higher than hand-watering pots. Plants won’t receive enough water and nutrients from hand-watering unlike in the case of flood and drain. Besides that, small portions of water and nutrients during the day are always better than one large feed once a day.
  • The factor of fresh oxygen. Cannabis plant receives fresh oxygen after each flood and drain cycle. Thus, such marijuana plant grows faster, it is healthier and produces a better yield.
  • You have the ability to adjust an amount of each nutrient in the solution, frequency of the flood and drain cycles. You can set the optimum feeding schedule suitable to the particular cannabis strain.
  • Useless and excessive nutrients will simply return to the reservoir and will not remain at the bottom of the pot. For example, nutrient salts that built up in the pot can cause harm to the cannabis plant.


There are 2 existing types of flood and drain systems that have their own advantages: the table system and the modular system.

Flood and Drain Table System

In case of the flood and drain table system, marijuana plants are located on a table’s surface, above the reservoir with the nutrient solution. The table has two fittings - for inflow and overflow (water out). The first fitting is located at the level of the table’s surface, another one – several inches above the surface - the overflow drain.

When the pump is working, the nutrient solution flows to the table’s surface through the inlet fitting. When the solution level reaches the overflow drain, it gets back into the reservoir. The whole system is similar to your bathtub where the overflow drain prevents it from overflowing. Other part of the solution that remains below the outflow drain, returns to the reservoir through the inlet fitting when the pump is turned off. The frequency of flood and drain is regulated by a programmed timer.

There are many growing mediums that can be used in the process like rockwool, clay pebbles, soil, cocos, expanded clay, fine gravel etc. Cannabis plants can be put into pots or you can use the whole tray so the roots are able to spread freely. According to the results and opinions, this is the most effective method to get the fastest growth and the biggest yield of marijuana. Flood and Drain table system is quite leak-proof that is good for home conditions when you grow plants in your room or an attic.

Modular or Bucket Flood and Drain System

The main difference of the bucket flood and drain system compared to the table one is that an individual pot is used for each cannabis plant.

The reservoir is connected with the main bucket through a tube and then each plant pot has a tube that leads to the main bucket as well. Flood and drain procedure is used for the main control bucket only. The system uses gravity to send nutrient solution to the pots. The main advantage of this system is that you can move any single cannabis plant with a pot and place it at the best location, for example under lights, so the plant can grow better. Additionally, the bucket system is easy to change by adding or removing pots, and you can grow many plants in different pots using one single reservoir.

Who might be interested in Flood and Drain system?

  • People who want to save their time and efforts while growing a big number of cannabis plants that can be maintained from one tank.
  • Growers who have individual environment for their plants and want to adjust the system according to it to get the maximum yield of marijuana.
  • No need to water each plant individually.
  • Avoiding nutrient salts build up in the root zone of the plant as well as allowing better oxygen circulation for the best efficiency of growing and producing a big yield of marijuana.
  • Flood and Drain system can be upgraded in size by removing or adding pots.

Three secrets to keep the system working:

  1. Write down the number of floods each day and also the amount of nutrient solution that you need to spend. The faster your cannabis plants grow, the more nutrent solution they need. So try to adjust the frequency of flood and drain and duration of each cycle taking into consideration the stage of growth and growing environment.

  2. The contents of the reservoir depends on growing medium and the power of the light. If you grow cannabis plants  under powerful grow lights, your plants will definitely need more water, that is why you should use dilute nutrient solution otherwise you run the risk of overfeeding. In case of cocos or soil which represent an absorbent medium, use a full-strength nutrient solution.

  3. Increase the number of floods gradually, do not jump from 3 floods per day to 6 floods per day. When plants grow bigger and increase in size, you have to increase the number of floods. Small and young plants require approximately 2 flood periods per day that last 15 minutes. You can add additional periods to a maximum of one fifteen-minute feed per hour when a plant becomes bigger. Usually, soil or other absorbent medium will make you change nutrient solution every 2 weeks, or if your particular cannabis strain requires more feeding - even more often.


  Growing marijuana

Grow With Us!

Subscribe today to get the latest and greatest growing methods sent right to your inbox!


Thank You For Subscribing!



Write a comment

Note: HTML is not translated!