As cannabis users, what we really care about is bud, but in terms of cannabis growing, healthy roots and stems are crucial to the overall health of the plants.  Indoor growing gives growers the maximum possible degree of control over growing conditions, but even outdoor growers can take action to resolve grow problems, provided that they stay alert.

Signs of root problems

As a human, if you lack food and water, you start to feel yourself becoming drained.  The same holds true of your marijuana plants.  You take in the nutrients you need through your mouth, your marijuana plants take in the nutrients they need through their roots and leaves.  So if your plants look miserable and there’s nothing obviously wrong with the leaves, then the problem is probably with the roots.  Another way to pick up root issues is to check the runoff water, if it’s smelly or has anything else wrong with it, then that’s also a pointer to problems with the roots.  The last key way to check for root problems is to look at the roots themselves.  Obviously this may be a bit of a challenge depending on what you’re growing and how, but it is an option and may be worth investigating.

Causes of root problems (and how to fix them)

Cannabis plant with watering system

Working out the cause of a root problem generally gives a pretty good pointer as to how to fix it.  When it comes to cannabis growing, particularly indoor growing, getting over enthusiastic about watering is possibly the number one cause of grow problems, especially root problems.  In simple terms, wait until your plant actually needs water before you give it any.  To check this, stick one of your fingers a couple of centimetres (an inch) into the soil (basically up to your first knuckle) and see if the soil feels dry.

If it does, your plant needs watering.  If you’re using normal soil and liquid nutrients fill a watering can to about a quarter of the volume of the pot you are using (so if your pot is one litre then use a quarter of a litre of water) and then water until you see the runoff come through the drainage holes at the bottom.  If you finish your watering without seeing runoff, then you probably have an issue with drainage.  If you are using super soil or something of that nature then fill your watering can to about a fifth of the volume of the pot and use all of it.  The reason you want to see runoff with liquid nutrients but avoid it with super soil is that in the former case it cleans away build up whereas in the latter it can wash away nutrients.

Root Rot image

After over watering, under watering is probably the next biggest problem, if your plants leaves feel dry, like it’s autumn already, then you probably need to step up the water you are giving it - and quickly.  If you continue to have problems then you may have to look at the soil.  Even though problems with the soil tend to come about as a result of other actions such as over watering or overfeeding (assuming you’ve chosen a quality soil), if the soil becomes too damaged you may need to fix it (e.g. by enriching it or improving drainage) or change it.  Pot size also matters.  Small plants are overwhelmed in big pots and big plants are stifled in small pots.  Just as you move a baby from a cot to a full-sized bed in gentle stages, so you want to keep your marijuana plants in pots which are right for their growth stage and move them as necessary.  The final common cause of root problems is temperature.  Humans dislike being too hot or too cold and so do marijuana plants.

Common stem problems and how to fix them

Long, stretchy stems

As with many grow problems in the cannabis world, avoiding the problem is generally easier than curing it.  Long, stretchy stems tend to be a sign that your plant is trying to grow up to the light source, hence you want to keep the light as low as you can without risking burning your plant.  If it does happen to you, you need to re-pot your plant, very gently and carefully so that the stem is under soil (the sooner you do this, the easier you are likely to find it).  This will cause the stem to grow new roots and continue growing as normal.

Rotting stems

rotting stems on a marijuana plant

The culprits for this one are likely to be over watering, poor drainage or overfeeding, in pretty much that order.  Be vigilant to any sign of stem rot and if you do notice it, check the aforementioned list very quickly.

Stem is changing colour

Issues with watering (over and under, but generally over), poor drainage and incorrect feeding (again over or under but typically over) can all be a factor here, as can heat, both too much and too little.

If you have any problems with your cannabis growing, then the points to check are water (including drainage), food, soil and pot size, temperature and the presence of pests.  If you’re still at a loss as to how to fix your grow problem, then remember that cannabis growing is popular around the world and hence there are a lot of helpful and knowledgeable people online to give you some advice, regardless of whether you’re indoor growing or outdoor growing.  As with all grow problems, regardless of whether they relate to cannabis or any other plant, the more vigilant you are and the quicker you take action, the more likely you are to save your plant.