Your plant can’t talk, but its leaves tell you a lot. Droopy, yellow, curled, spotted or stretched: each symptom points to a short list of causes. This page is the starting point. Match what you see, then follow the link to the full guide for that problem.
Check these 5 things first
- Water. Push a finger an inch into the soil. Wet means wait. Dry means water slowly until a little runs out of the bottom. More plants get sick from too much water than too little. See our cannabis watering guide.
- Light. Outdoors or in a window, the plant wants at least 4 hours of direct sun, and 6 or more is better. See how much sun a weed plant needs.
- Temperature. Cannabis likes about 65 to 80°F. Hot afternoons and cold nights both cause stress. See the best temperatures for cannabis.
- Food. Too much fertilizer burns a plant faster than too little starves it. If you grow in super soil, the food is already in it, so don’t add more. See what super soil is and the best soil for cannabis.
- Pests. Turn a few leaves over and look underneath. Tiny dots, webbing or bugs mean pests, not a feeding problem.
Symptom checker: what your plant is telling you
| What you see | Most likely cause | What to do | Full guide |
|---|---|---|---|
| Leaves droop, soil is wet | Too much water, or a pot that doesn’t drain | Stop watering until the top inch is dry. Make sure water can run out of the pot. | Why cannabis leaves droop |
| Leaves droop and feel limp, soil is dry, pot feels light | Not enough water | Water slowly until a little runs out the bottom. Leaves should perk up within hours. | Cannabis watering |
| Leaf edges curl up like a taco, tips look crispy | Heat stress, or a light that’s too close | Cool the room, add air flow, raise the light, or move the pot out of harsh afternoon sun. | Best temperatures |
| Stems or leaves turn purple, growth slows in cold weather | Cold nights (some strains also turn purple naturally) | Bring the plant in or away from cold glass at night. Purple alone on a healthy, growing plant is fine. | Best temperatures |
| Tiny white or yellow speckles, fine webbing under the leaves | Spider mites | Act fast: isolate the plant and treat the undersides of the leaves. | Spider mites on weed plants |
| Holes, sticky spots or visible bugs | Other pests | Start with the gentlest fix. Don’t spray buds once they’ve formed. | Cannabis pesticides |
| Lower leaves turn yellow from the bottom up | In the last weeks of flower: normal, the plant is using up its stored food. Earlier on: overwatering or a hungry plant | Late in flower, leave it. Earlier, check the water first, then the soil. | Best soil for cannabis |
| Brown, burnt leaf tips | Too much fertilizer (nutrient burn) | Stop feeding. In super soil, the plant doesn’t need extra nutrients. | Super soil |
| Tall, thin, floppy seedling | Not enough light, so it stretches to find more | Move it to brighter light, or bring the light closer. | How much sun cannabis needs |
| Chewed leaves, knocked-over pot | Pets | Move the plant out of reach. Cannabis isn’t safe for dogs and cats to eat. | Growing around pets |
| Not sure which part of the plant you’re looking at | – | Learn the names first: fan leaves, sugar leaves, nodes and pistils. | Weed leaf names |
Prevent problems before they start
- Start with good soil. Soil with the nutrients already mixed in takes feeding mistakes off the list. Our grow kits come with super soil, so you add your seed, water and harvest.
- Give it air. Thin out crowded growth so air moves through the plant. That cuts down on mold and pests. See pruning cannabis for bigger yields.
- Plant a few neighbors. Some herbs and flowers help keep pests away outdoors. See companion plants for cannabis.
- Avoid the classic beginner slips. Overwatering, overfeeding and too little light cause most of the problems on this page. See common mistakes when growing weed.
Cannabis plant problems FAQ
Why are my cannabis leaves turning yellow?
If it’s the lower leaves in the last weeks of flower, that’s normal. Earlier in the grow, the most common causes are overwatering and a plant that has run out of food. Check the soil moisture first.
Why are my weed plant’s leaves curling up?
Leaves that curl up at the edges usually mean heat stress or a light that’s too close. Cool the plant down and give it more air flow.
Can a droopy cannabis plant recover?
Yes. A plant that droops from too much or too little water usually recovers within a day or two once the watering is fixed.
Should I use pesticides on cannabis?
Use them only when you need to, start with the gentlest option, and never spray the buds. Whatever you spray ends up in what you smoke. See our guide to cannabis pesticides.
Only for adults 21+ in states where home growing is legal. See our state-by-state guide.
