Identify & Fix Cannabis Problems
Cannabis Plant Diagnosis Tool: find out in seconds what’s wrong with your plant – and how to fix it the right way.
How would you like to start?
Let our Cannabis Plant Diagnosis Tool guide you with a few questions — or browse the most common symptoms and causes yourself.
Let’s figure out together what’s wrong with your plant
Targeted questions about symptoms, growth stage and growing conditions — then you get a clear assessment and first steps to take right away.
We know about it and are already working on it — the Plant Diagnosis Tool should be back up in a few hours. You can try again anytime with the button above. Until then, you can often find your problem right in the topic overview:
Go to the topic overviewUpload a photo of your plant (optional)
Your photo helps us make the diagnosis tool more accurate. We review every image personally before it’s used.
What is your plant showing?
Yellow leaves
- even yellowing
- often starts on lower leaves
- leaf feels soft
- no visible pests
Drooping leaves
- leaves hang down
- soil is wet or too dry
- stem stays upright
- discoloration only in late stages
Spots on the leaves
- yellow or brown spots
- irregular patterns
- spots are spreading
- leaf stays green at first
White dots on leaves
- tiny white or silver dots
- fine webbing visible
- leaves lose color
- undersides infested
Stunted growth
- plant barely grows
- new leaves very small
- very short internodes
- no visible deficiencies
What could be wrong with your plant?
Nutrient deficiency
A lack of nutrients causes yellow leaves, spots and weak growth.
Overwatering
Watering too often damages the roots and leads to drooping leaves.
Light stress
Too much light or heat causes burnt leaves and stress reactions.
Pests
Tiny insects cause spots and white dots and weaken the plant.
Climate stress
The wrong temperature or humidity can slow growth dramatically.
pH problems
The wrong pH blocks nutrient uptake – even when you feed.
Root problems
Root rot and damage in the root zone slow growth from the bottom up.
Nutrient burn
Too many nutrients burn the roots and show up as brown leaf tips and edges.
Fungal Diseases & Mold
Bud rot (botrytis, gray mold), powdery mildew, fusarium and more — catch fungal diseases early and save your harvest.
Cannabis plant diagnosis — a step-by-step approach
A targeted cannabis plant diagnosis doesn’t start with the specific fungus or pest, but with the right category: most problems fall into four main groups — nutrient problems, pests, fungal diseases and environmental stress. If you sort out which of these four you’re dealing with first, instead of jumping straight to a single symptom, you’ll reach the right diagnosis much faster — it’s the same principle professional plant protection services use, such as Germany’s Julius Kühn Institute (JKI). You’ll find a detailed overview of all four categories in our plant disease guide.
A first look often tells you a lot: even yellowing or discoloration usually points to a nutrient deficiency or a pH problem. Visible insects, webbing or small holes suggest pests. A white or gray coating, dark spots with rings or a rotten smell point to a fungal disease. Burnt, curled or wilted leaves without visible pests usually point to climate or light stress.
Where and when a symptom appears matters just as much as the symptom itself. If the problem starts on old, lower leaves, it’s often a mobile nutrient deficiency. If it shows up first at the top on young shoots, light stress, pests or immobile nutrients are the more likely cause. If it appears suddenly after you did something — fed, transplanted, changed the light — you can often trace the cause right back.
For a quick first assessment, our Cannabis Plant Diagnosis Tool at the top of this page is often all you need — a few targeted questions are usually enough to narrow down the most likely cause. Want to dig deeper into one area? Our topic hubs cover everything in depth: Nutrients, Pests, Fungal Diseases & Mold and Climate.
For an even more precise assessment, you can optionally upload a photo of your plant in the Cannabis Plant Diagnosis Tool — it helps us classify unclear cases and keep improving our database. With acute, fast-spreading problems like a heavy fungal infection or a major pest infestation, the rule is: act right away instead of waiting — the sooner treatment starts, the better your chances of saving the harvest.
Still haven’t found your answer?
Every plant is different. If you’re not sure what your plant is showing, send us your question directly — we’ll help you find the cause.
Frequently asked questions about the Cannabis Plant Diagnosis Tool
How can I quickly find out what’s wrong with my cannabis plant?
Your best bet is to start with the Plant Diagnosis Tool at the top of this page — a few targeted questions about symptoms and growing conditions are usually enough for a clear first assessment. You can also search for your symptom directly in the topic overview.
How do I tell a nutrient deficiency from a disease?
Nutrient deficiencies usually show up as even discoloration without visible pests, while fungal diseases often cause spots, coatings or rotting areas, and pests are usually visible themselves (insects, webbing, feeding damage). When in doubt, take a close look at the leaf undersides and stems with a magnifying glass.
Can one problem have several causes at the same time?
Yes, that happens more often than you’d think. The wrong pH can lock out several nutrients at once, and stressed plants are more susceptible to pests and fungal infections. Still, always start with the most likely single cause and work through the rest systematically.
How fast do I need to act on pests or fungal infections?
Ideally right away. Under favorable conditions (warm, humid climate) both spread very fast and are much easier to stop at an early stage than once the infestation is heavy. Isolate affected plants if you can and start treatment immediately.
What do I do if the Plant Diagnosis Tool doesn’t help me?
In the results step you can optionally upload a photo of your plant — that helps us classify your case more precisely. You’ll also find more in-depth information on each area in the topic overview above or directly in our topic hubs (nutrients, pests, fungal diseases, climate).
Is the plant diagnosis on this page free?
Yes, the entire Plant Diagnosis Tool and all articles and hubs on PlantClue are free to use, no sign-up required.
Ready for the next step?
Understand your plant from the ground up – from the right growing medium to a successful harvest.
