Nutrient Lockout: What It Is And How To Solve It
3 min

Nutrient Lockout: What It Is And How To Solve It

3 min
Growing Seedshop

Nutrient lockout is a common problem among growers but recognizing it and fixing it requires some basic knowledge. Less experienced growers may not recognize a nutrient lockout, making the problem worse by doing the opposite of what is needed to restore their plants’ health. Learn about nutrient lockout and how to fix it and how to avoid it!

A nutrient lockout is among the most common problems cannabis growers can experience during a grow. Unfortunately, less experienced growers will not always recognize a nutrient lockout as what it really is. Many times, the grower might even do the exact opposite of what would be needed to fix the problem. In this blog, you will learn what nutrient lockout is and most importantly, how to fix it and how you can avoid it in the future.


When your cannabis plants are experiencing a nutrient lockout, this means that they cannot take in the required nutrients to grow properly. The result of a nutrient lockout can be growing deficiencies such as discoloured leaves, poor yield and in the worst case scenario a lost grow altogether.

A nutrient lockout can be caused by a variety of things. Common reasons for your plants not being able to take in all the required nutrients could be wrong pH levels for your water, nutrient solution or soil (such as when the pH is too high or too low) or a chemical reaction between nutrients that can cause your plants to not uptake nutrients. Build-up of salt deposits in your soil from the use of mineral (non-organic) fertilizers and nutrients can also be a cause for a nutrient lockout.

What is important to know about a typical nutrient lockout scenario is that all the required nutrients are normally indeed present but the plants cannot take them in. Cannabis plants, for example, rely on a rather tight window of optimal pH levels where they are able to uptake nutrients optimally. If the pH is off, the plant cannot absorb certain nutrients even if they are present.


Many new growers see the symptoms of a nutrient lockout such as yellow leaves or overall poor growth and they think that the problem is not giving the plant sufficient nutrients. This thinking is of course not even that far off since the signs of a lockout can indeed look similar as if the plant would not get those nutrients in the first place, except for the underlying cause.

However, rather than fixing the actual problem, such as a wrong pH, salt build-up or whatever the reason for the nutrient lockout may be, growers may be tempted to give even more nutrients, thinking this would solve the problem, essentially making the problem even worse!


To fix a nutrient lockout and restore your plant’s ability to absorb nutrients you can perform a nutrient flush. This means you cleanse the growing medium by saturating it with clean water or with water and a special flushing agent. If you grow in soil, the common flushing procedure is to give as much clean and properly pH-ed water until half of the water comes out. Following the flush, it is recommended to give your plants the correct amount of nutrients. For hydroponically systems, the methods vary, but the underlying principle is the same: you cleanse your system to get rid of salt and mineral build-up, which is the actual reason for the lockout.

Seasoned growers are usually performing regular routine flushes to prevent problems before they can occur. It’s a good idea to flush your pots or hydroponic system in regular intervals, like when you move your plants to flower and then a second flush halfway through flower.

Also very common are nutrient lockout problems caused by an altogether incorrect pH level of your water or nutrient solution. Cannabis prefers pH levels that range from 5.5-6.5. If this is significantly off beyond this scale either way, a nutrient lockout and growing problems are likely. To solve this problem you need to always make sure about the correct pH levels of your water or nutrient solution. To start fixing your plants, perform the flush as described above with water that has the proper pH. Water with water that has the correct pH level and the problems from the lockout caused by improper pH should go away in a few days.


Sometimes, the requirement to feed your plants heavily can be the main reason for a nutrient lockout. You can reduce your plant’s nutrient requirements if you trim them heavily. Less plant mass means that your plant needs fewer nutrients to feed in order to grow properly.

The amount of light also plays a role in how much nutrients your plants need. This can be important when you switch your plants from the vegetative phase into flowering. Only change the amount of light and nutrients gradually and slowly to allow the plants to adapt to their new environment and to reduce stress.

Organic nutrients can help to avoid nutrient lockout. Non-organic nutrients and fertilizers contain minerals, including salt that will build up over time, changing your growing medium’s pH levels and therefore possibly leading to nutrient lockout. Organic fertilizers don’t contain those high amounts of salt which means they are far less likely to cause nutrient lockouts. However, even with organic fertilizers, routine flushes are always a good practice.

Nutrient lockout is one of the most common problems especially for less experienced cannabis growers. When you have learned how to recognize and to solve nutrient lockout, you have the best chances for a successful grow and an abundant harvest!



Written by: Georg
Based in Spain, Georg spends a lot of his time not only geeking out at his computer but in his garden as well. With a burning passion for growing cannabis and researching psychedelics, Georg is well versed in all things psychoactive.

      Find out about our writers  

Read more about
Growing Seedshop
Search in categories