PPM is another important factor when it comes to water quality. Ppm, or parts per million, is a method of measuring the amount of minerals that have dissolved into the water source being used. So, a reading of 90ppm will indicate that there are 90 milligrams per litre of minerals present within the water source.
Cannabis plants consist of approximately 90% water, and the substance is required during various vital physiological process such as photosynthesis and transpiration. When using a poor quality water source to supply cannabis plants, these processes may be less efficient than they can be, or in worst case scenarios, disruptive.
However, there are telltale signs that will display it’s time to once again water your plants. Checking the top inch of soil is a promising way to identify this. Wait for this section of the soil to be dry before watering again in order to avoid overwatering. Once you have done so multiple times, you should start to figure out how long it takes in between each watering, and then you can go by that length of time instead.
There are many contributing factors involved when it comes to a successful and bountiful cannabis grow. Lighting, nutrients, airflow, and humidity all play important roles in optimal growth and vibrancy of a crop. Water, however, is one of the most important aspects of keeping cannabis plants healthy and strong.
TDS meters, devices that measure total dissolved solids, can be used to measure the ppm of a water source.
Reverse osmosis filters are capable of removing between 95-99% of dissolved salts within a water sample and is therefore a standard method of cleaning water on an industrial scale.
1. Underwatered cannabis plants will look very weak, lifeless, and will show signs of wilting. Its no wonder they begin to look this way considering the vital role of water in plant physiology. The wilting of underwatered cannabis is different from the plump curling of overwatering – even if only subtly. Leaves will be fragile, brittle and even papery. They will look lifeless and drab. Another sign of an under watered cannabis plant an extremely dry growing medium, such as crispy soil.
To produce healthy plants, you need to keep a close eye on the amount of nutrients your plants are receiving. To do this, use trays to catch the runoff when you water your plants, and analyse both its pH and PPM (parts per million).
Being aware of the PPM within water allows growers to avoid giving their plants too many or too little minerals. A lack of minerals may lead to deficiencies, whereas too many may cause burning to occur. Cannabis plants prefer a ppm of around 500 when in the vegetative phase, and favour a ppm of around 1000 during the flowering stage of the grow cycle.
We explore how to recognise and fix cannabis over and underwatering, as well as the importance of good quality water.
How to Water Cannabis Properly
Sometimes plants will be droopy no matter what you do, and the true cause is the plant is rootbound and needs a bigger container!
Overwatering does not always mean you’ve been giving the plant too much water. It can also mean that you’ve been giving the plant water too often, or growing plants in a growing medium that holds onto water without enough air, or doesn’t have good drainage out the bottom.
Cannabis plants use their roots to get oxygen, almost like they’re breathing. Oxygen is dissolved in water, and there’s also air pockets in their grow medium to provide a source of oxygen. When you water your plants too often, the roots end up sitting in stagnant water. The reason your plants droop is because basically their roots are starving for oxygen.
Add water until you see some at least 20% extra runoff water drain out the bottom of your pot. Go back to step 1.
Overwatered cannabis plants are droopy with leaves that curl down. As a result of overwatering, leaves often turn yellow or show other signs of nutrient deficiencies (especially when it comes to younger plants and seedlings!)
This cannabis plant has green healthy leaves, but as a result of overwatering it’s stunted and small even though its more than a month old.
You should see water coming out the bottom within a minute or two after watering. Then don’t water your plants again until the soil is dry up to your first knuckle.
The drooping cannabis plant below did not have drainage holes (water could not drain out the bottom of the pot). After watering the plant which appeared healthy the night before, the grower came back to this drooping plant the next day – this case of overwatering was caused by too much water being held near the roots due to lack of drainage:
Overwatering and underwatering cannabis plants are easy to do and can cause multiple symptoms including slow growth. Learn to recognize and fix these issues.