What is flushing?

Flushing involves giving your cannabis plants straight pHed water instead of a nutrient solution. Flushing can and should be done at many times throughout your grow. With our feed schedule, we recommend growers flush with pHed water every third feeding. Additionally, you may need to flush your plant if any nutrient lockout occurs due to an excess build up of nutrients in your growing medium.


For soil and coco growers, flushing means watering your plants with only water and no nutrients. For hydroponic growers, flushing means switching out your nutrient solution with straight water. 


hydroponic roots


Flushing for hydroponic growers will involve fully draining your reservoir, cleaning it if necessary, and refilling it with plain pHed water. This water should be pumped through the system, discarded, and the reservoir filled again with straight water. Let this run through for 24 hours before refilling with your nutrient solution. You will have to do this every 1-2 weeks.


Why is flushing important?

Flushing removes nutrients, salts, and minerals from your growing medium so your plant cannot continue to absorb them. This forces your plant to use up the remaining nutrients it has stored inside itself. This results in a cleaner end product.


Perhaps one of the most important flushes will be your final flushing stage. When your plants are ready to be harvested it is recommended to do a flush. This flush can last anywhere from a couple days to a couple weeks depending on what growing medium you are using. 


Growers often flush their plants with straight pHed water a few days or a couple weeks before harvest. Growers who fertilize their plants with nutrients will want to flush them clean of any remaining nutrients. It is believed this will increase the quality and taste of your end product!


cannabis joint


Benefits of Flushing

  • Smoother smoke
  • Better taste
  • Enhanced smell

You should flush your cannabis plants when they are almost within the harvest window. Your plants should be almost ready to harvest but can still stay on the plant for a bit longer. This will result in the highest quality bud. 


You’ll know your buds are ready to be harvested when you inspect the trichomes. Buds are ready to harvest when the "hairs" (pistils) have turned dark and curled in. You should be able to see a solid bud. ⁣



Your plant should have clear trichomes with a few that have turned milky. This signals it is ready to be flushed. When growing in soil, you’ll generally want to flush 1-2 weeks before harvest. 


Pay attention to the trichomes!⁣

Trichomes are the crystals or frost that show up on your buds and leaves. They make cannabis sticky. They can be hard to see with the naked eye so we recommend using some sort of magnification. ⁣
  • Clear trichomes mean the buds are not ready yet. ⁣
  • Once they turn milky they will be at peak THC levels and ready for harvest. 
  • Clear trichomes should look somewhat like glass. It can be hard to tell the difference between clear trichomes and milky trichomes if it is your first time seeing them. ⁣
  • If you wait to harvest until the trichomes turn amber in color, it will result in a bud with a lower level of THC but will produce a more relaxing body high.⁣




flushing stage


If you flush your plants too early, it could result in buds that aren't fully developed!


Some growers find the flushing stage to have no effect on the final product. With so many strains and growing methods out there, it is very plausible that flushing or not will make little difference on some plants. Still, we maintain that flushing is important to a high quality end product. Our testing has shown it creates a cleaner end product with a smoother smoke and a better taste.


Some growers use less nutrients in their feeding schedule which may result in less nutrients leftover in the buds without a flushing stage. While using Future Harvest nutrients we believe a flushing stage will leave you with better tasting and smelling buds. 


future harvest plant flush


Future Harvest offers our Plant Flush product. Plant Flush will lock out the roots of your plant so no more nutrients can be absorbed. This forces your plant to use up the nutrients it has stored in itself. It is an efficient way to ensure a cleaner end product than simply flushing with pHed water or not flushing at all. 


  • Your growing medium can retain high levels of residual salts. The plant can absorb these near the end of flowering which can result in a poorly burning end product. ⁣
  • To prevent this, a flushing stage is essential to achieve a high quality end product. ⁣⁣
  • Straight water may be used, or add Plant Flush for a more effective flushing stage! ⁣⁣



watering can flushing stage



When To Flush


You will need to flush at the end of your grow when your plants are almost ready to be harvested. But there are other times you will need to flush as well!

  • When you are experiencing a nutrient lockout it is often caused by an excess build up of nutrients in your growing medium. A water flush will flush out the nutrients and give you a blank slate to start from. You may have to flush repeatedly to ensure your plant is clear of all nutrients before introducing new nutrients into your growing medium. 
  • Flushing should be done every third feeding. We recommend a straight water flush every third feeding for best results. Always make sure you are pHing your water before flushing or feeding.
  • Some growers flush when switching from veg to bloom.
  • Some growers flush when switching their nutrient line. 


hose flushing stage


If you’re flushing cannabis plants you’ll want to ensure you are doing it at the right time. Flush too early and you could stunt the growth of your plants and have a smaller yield. Do it too late and it can result in a harsh smoke even after drying and curing. 


Drying and Curing

After your flush and harvest, it is crucial to dry and cure your buds. 


drying and curing cannabis in jars 

Why is drying and curing your buds important?⁣

  • Improves taste and smell⁣
  • Improves smoothness and reduces harshness of smoking⁣
  • Reduces chance of mold⁣
  • Increases potency ⁣
Drying and curing removes the chlorophyll from your bud which results in a better taste and smell from your end product!

Curing is the process of drying your buds, normally in a glass jar. Only fill your jar 2/3rds of the way to allow for air inside. You should store them in a cool, dark place and check on them 1-2 times a day. ⁣


Make sure your cannabis is dry before curing or mold can occur. You will know when your buds are dry when you can easily snap the stems.


Be careful not to dry your buds too fast. ⁣


When curing, allow for humidity to enter the jars to prevent them from getting too dry. If your buds get too wet they can mold, if they are too dry then they can get crumbly. You want a happy medium. Keeping the humidity levels between 58-65% will help to keep them just right.⁣

The slower you cure your cannabis, the more terpenes you will preserve! If your cannabis is properly cured, you can store it for up to 2 years without losing potency.⁣


drying and curing cannabis in jars


Drying and Curing Steps 

  1. Harvest your plant⁣
  2. Trim off leaves⁣
  3. Hang your buds to dry ⁣
  4. Once your buds are dry (4-10 days), carefully manicure your buds with scissors and put them into sealed glass jars (filling them 2/3rds full to allow room for air)⁣
  5. Open the jars for a few minutes every day for 1-3 weeks⁣

temperature and humidity


Drying Temperature & Humidity: ⁣

  • 70°F (21°C)⁣
  • 45-55%⁣

Jar Temperature & Humidity: 

  • 70°F (21°C)⁣
  • 58-65% humidity⁣


The flushing stage can make or break your grow. 


Imagine harvesting your beautiful buds, caked up with frosty trichomes, drying and curing them to perfection, and then coughing a lung up after smoking all your hard work!


If you don’t flush before harvest, all your dedicated work could be ruined! If a flush is not performed at the end of your grow it can produce a harsher smoke in your end product. This harsh smoke comes from the leftover minerals and nutrients in your buds that stick around if they are not flushed out.


Do you flush your plants before harvest? How long do you like to flush for? Share your routine in the comments!



Any questions? Email us at marketing@futureharvest.com or send us a message on Instagram @futureharvestdevelopment and we will help you as best we can!