by Nebula Haze
When I was first learning about how to grow cannabis, I learned about the importance of pH to prevent nutrient deficiencies. But sometimes your pH is in the recommended range and your marijuana plants leaves are still showing signs of nutrient deficiencies.
What else besides incorrect pH causes nutrient deficiencies in cannabis plants?
Basically, when it comes to cannabis plants, your plant starts experiencing nutrient deficiencies if the pH is too high or too low at the roots. This is because the chemical structure of nutrients actually changes at different pH levels, and some versions are easier for the plant to absorb than others.
By giving your plants good cannabis nutrients and managing the pH, you’ll be able to prevent most nutrient deficiencies, ensuring your plant grows as fast and healthy as possible.
But what do you do if you’re using good nutrients and the pH is right but you’re still getting nutrient deficiencies?
When it comes down to it, nutrient deficiencies usually start at the roots, whether it’s pH or something else. This looks like a nutrient deficiency, but it’s actually caused by overwatering.
One of the most common reasons to see deficiencies when the pH is correct is the plant is being over or under-watered, which can also be related to the drainage of the grow medium and the container your plant is in. When the plant isn’t getting the right ratio of water and air at the roots, it will tend to start showing deficiencies even if everything else is right. Other issues with roots are also common culprits.
Causes of Most Nutrient Deficiencies
- PH is too high or too low ← Most Important!!! But if you’re on this page you’ve probably already got this covered.
- Not enough nutrients overall (here are recommended cannabis nutrients)
- Over-watering
- Under-watering
- Pot is too big for the size of the plant
- Plants are rootbound (been in the same pot too long)
- Too hot (and rarely too cold)
- Bugs or pest infestation
Note: Basically anything that makes your plant droopy is likely to cause nutrient deficiencies, too.
Although pH and watering practices are probably the most important thing to pay attention to, there’s more than just pH as far as your plant roots are concerned. The “alkalinity” of your water is also important. Alkalinity is related to pH, but it is also its own thing. In a way, alkalinity measures how much “stuff” is in the water that causes the pH to go up. And this also affects nutrient absorption.
If you’re still having trouble after going through the steps above, and your pH is in the right range…
- If you have “hard” water, you should generally aim for a slightly lower pH (aim for around 6.5 pH for soil and 6.0 pH for coco or hydro).
- If you have “soft” water, you should generally aim for a slightly higher pH (aim closer to 7 pH for soil and 6.5 pH for coco or hydro).
I hope that helps some people dial in the correct pH based on their starting water.
Jump to…
Tips to Growing Top-Shelf Buds
7 Steps to Fix 99% of Growing Problems
