Then again, the lack of flushing shouldn’t be an issue as no synthetic or external nutrients are added to this medium. Instead, plants rely on microorganisms to break down organic matter and deliver it to the roots.
Preventing nutrient lockout can be accomplished via routine flushing. By flushing your plants once before flowering begins and once halfway through flowering, you’ll minimise the chances of nutrient buildup.
Flushing the marijuana plants before harvest can make all the difference in the best bud, or horrible hash. This small task is simple and super easy to do. Just add water! Be very careful, as the timing of the flush can play a critical role in this process.
The act of flushing a plant is using plain water to actively remove any nutrients in the soil. A large amount of water is passed through the soil and drained away on a regular basis. Any minerals and nutrients present in the soil are washed away over time by the water, leaving the soil clean.
The what, how, and why of flushing cannabis plants.
Flood the soil with as much fresh water as it can hold. Leave this for a few minutes to allow all of the nutrients to be picked up, the flood the soil again to flush it all away from the plant. If you are indoors using pots, notice the colour of the water that is draining from the bottom of the pot. It will be stained and look dirty. This is where a TDS (total dissolved solids) meter will come in handy. If you were to collect and measure the TDS of the “drained off” water, it would be around the measurement of 1300ppm, which is pretty high. It is important to keep flushing the plant until this number drops to a level of 50ppm, or at least until it is close to matching the TDS of the fresh water that you are using to flush with. The colour of the draining water will lighten up and appear to be cleaner. You want to get as much of the dissolved minerals away from the plant as you can.
Nutrient lockout can be an inconvenience at best and devastating at worst. As the old saying goes, prevention is better than a cure. It’s best to take steps to avoid nutrient lockout as opposed to tackling it later down the line.
Flushing your cannabis plants is a straight forward process. Whenever you would normally feed, you flush instead. Untreated tap water is all you need to use for flushing, just be sure to make sure the pH is at a safe level for cannabis. Most well water contains a healthy pH level and will not need treatment, but if it is necessary for you to add treatment to adjust the pH of your flushing water, feel free to do so. The pH adjustments will be the only thing you will need to be concerned about.
Nutrient lockout can be caused by both salt buildup and incorrect pH levels. It can be solved by flushing affected plants with plain water. The fluids push nutrients out of the soil and wash away the buildup, allowing roots to once again freely uptake nutrients.
Flushing cannabis before harvest can makes the difference between a smooth or horrifically harsh smoke. Here is how to do it.
Different growing mediums require different flushing time frames before harvest:
Trevor is a freelance writer and photographer. He has spent years in California working in the cannabis industry.
Your final flush should occur before harvest. This will force the plant to use the nutrients stored within itself in the final week or so. If its nutrient reserves are not used by the plant or broken down, they will affect the quality of your harvest’s smoke and flavor.
Once you’ve properly flushed and harvested your garden, it’s important to dry and cure the cannabis correctly. It is through a quality flush and a long cure that your cannabis will be able to fully express itself.
Once again, flushing cannabis simply involves running pure water though the soil or medium. When trying to stop a nutrient lockout or when switching nutrients, perform a flush by excessively watering your plants with water that has a pH level between 5.5-6.5 (for hydroponics) or 6.0-6.8 (for soil). Fully saturate your pots, and repeat 15 minutes later. The flush should clear any blockage and make room for your new feeding schedule.
When looking to perform a flush before harvest, there are more factors to consider. Make sure your plants will be ready for harvest once the flush is complete. Flushing too early or too late will result in a lower-quality product.
By paying attention to the trichomes on your plants, you’ll be able to tell when your plants are ready for a flush. If flushing two weeks prior to harvest, you should begin when you start seeing the first trichomes turn milky.
To be certain a flush was successful, you can use a TDS (total dissolved solids) reader to determine how pure the water runoff is. You want the TDS reading of the water draining out of the pot to be close to the TDS reading of the pure water you are flushing with. This reading will ensure that the nutrients have been washed out of the soil.
Think of it as someone changing their diet. You can fill your fridge with new types of food, but you might find yourself running out of room if you never removed the old food. By removing the old food, you are clearing a path and starting anew.
Flushing is when you stop feeding your cannabis plants nutrients and give them water. The process is generally as easy at it sounds, but it's crucial to know precisely when and how often to flush.