You are hereUnder-watering
Problem: If your plant is drooping, then it's usually a sign of either over or under-watering.
If your soil or soilless medium look bone dry, or if you know that your roots have dried out, than skip right down the the solution section, as you definitely have a case of underwatering.
Not Sure? If you're not sure whether your plant needs more or less water, how do you figure out exactly why your plant is drooping?
1.) Determine: Is my plant over-watered?
A cannabis plant does not get over-watered because it's given too much water at once - overwatering is caused by the plant being watered too often, or if the plant does not have proper drainage (which means the growing medium is taking too long to dry out).
2.) If not over-watered, does my plant have root problems?
Growing hydroponically? When you see signs of wilting and overwatering in a plant that is growing hydroponically with the roots in water, usually that's a sign of a root problem like root rot.
In fact, all cannabis plants can sometimes display wilting/drooping symptoms that are actually the result of root problems.
3.) You may be seeing symptoms of under-watering
So if you read the short description in step 1 about what causes overwatering (and you're sure you haven't overwatered your cannabis plants), and you're certain you're not seeing signs of root problems, than your cannabis plant might be drooping or wilting because it needs more water.
If you've been underwatering your plant, its leaves will look limp and lifeless, like these plants.
Symptoms of underwatering look the same whether your cannabis plant is growing in soil or a soilless growing medium like coco coir or perlite.
Don't wait until leaves droop to water your potted cannabis plant! While it is generally a good idea to let your potted cannabis plant dry out a bit after watering (watering too often causes its own problems), you should always water your cannabis plants again before the leaves start drooping.
This is the case for cannabis plants grown in both soilless growing mediums and soil.
First-time growers tend to overwater their plants, but underwatering happens too.
So you're pretty sure your plant is under-watered. A thirsty cannabis plant will usually perk up quickly after the roots are given water.
Click here to see time-lapse of under-watered marijuana plant coming back to life
1 picture taken every 75 minutes. Strain is Island Sweet Skunk. Used with permission. By micks_trichs.
Watch another time-lapse - middle plant is very under-watered and perks up after getting water
6 plants, 1 photo per minute for 125 minutes. Used with permission. By micks_trichs.
Learn about ones of the best ways to properly water your potted cannabis plant every time...
How to water cannabis properly (for soil and most soilless mediums)
Wait until the top of the growing medium is dry about an inch deep (up to your first knuckle).
Add water until you see some at least 20% extra runoff water drain out the bottom of your pot. Go back to step 1. (If water does not come out quickly or pots take more than 5 days to dry out for step 1, you may have a drainage problem)
Another simple way to tell if a potted plant is ready to be watered is to pick it up and tell if it feels heavy or not.
As plants use up all the water in their pot, it will get lighter. If you need something for comparison, you can get an extra pot and fill it with your growing medium. Now you can use this extra container for comparison with your potted plants as it represents the 'dry weight' of your growing medium. If you pick up a potted plant and its feels just slightly heavier than your dry pot, then you know it's time to water your plant. After a while you get a feel for how heavy your plants need to be and you may not even need the extra pot anymore.
Need more help?
If your plant is experiencing "the claw" and not just normal drooping (the ends of leaves are curling like a claw or pointing down like talons), then you may actually have a nitrogen toxicity (too much nitrogen).
These Plants Are NOT Over or Underwaterd, These Leaves Show Signs of
("The Claw", tips bent down, curling / clawing, dark green leaves)