by Nebula Haze & Sirius Fourside
Question: Why do my marijuana seedlings get tall and die? They grow all stretchy with long stems, and don’t make new sets of leaves. ~Many Growers
Answer: Tall seedlings need LIGHT.
Get bushier plants with a great grow light, like this SF-2000 LED.
Wide, bushy cannabis plants produce more weed!
When marijuana seedlings are growing tall and thin, it means they need more light. Typically from a weak grow light.
Example: This cannabis seedling grew tall and thin (almost falling down) because it is starving for light.
Plants without enough light keep getting tall without growing many leaves. It is “reaching” up towards the light.
More “leggy” cannabis seedlings. These seedlings each need their own pot and a lot more light!
When young marijuana seedlings are starving for light, they often show signs of lots of other problems, but if they’re getting really tall without making any leaves, it’s a sure sign it needs a brighter environment.
To increase the amount of light, you either need to get stronger grow lights (what grow lights work for growing cannabis?), or move your current grow light closer to your plants.
Some growers bury the extra stem to make seedlings short again, which works, but as long as you start giving your seedling light it will do a “push up” and rise back up, strengthening its stem in the process! Here’s what to do right away…
Get a Small LED Grow light
A small cheap LED grow light like the SF-1000 can support as many cannabis seedlings as you can fit in a 2’x2′ grow space. Seedlings under this grow light won’t stretch as long as you keep it the recommended distance away.
The SF-1000 is powerful enough to grow a single plant to harvest, so it can be a great starter light for a grower just “dipping a toe” into the cannabis grow world. Learn more.
After adding light for your too-tall cannabis seedlings, the plant should start growing leaves closer together. However, the original stems will not get new leaves.
Should you bury the stems? No need.
Some growers bury taller plants to “shorten” the stem. However, that can cause the stem to rot under the soil.
Usually once you give light and let the plant grow out naturally, the stems don’t seem nearly as long. No need to bury the stems!
A seedling might be tall…
…but give it light and you soon can’t tell.
Learn about other common cannabis seedling problems!
What Do Healthy Seedlings Look Like?
1.) Overwatering
2.) Underwatering
- Symptoms: Drooping leaves and/or wilting
4.) Too Much Heat
- Symptoms: Leaves fold in the middle so they look like canoes/tacos, leaves turn up at the edges, wilting, strange spotting, symptoms usually appear after temperature starts climbing
- Symptoms (too much light): burned or crinkled leaves
- Symptoms (not enough light): seedlings are too tall with too much space between nodes. Looks stretched/leggy and tends fall over
Frequently Asked Questions About Seedlings
Jump to…
- Complete Beginner’s Guide to Growing
- How to Grow Weed in 10 Steps
- Cannabis Nutrients
- Which Grow Lights?
- Soil or Hydro?
- Where to Get Seeds (even in the U.S.)
- Germination Help
Plant Problems & Symptoms
- Cannabis Problems Guide
- Diagnose Your Sick Plant
- Bugs, Mold & Other Cannabis Pests
- Stop Nutrient Deficiencies!
- 7-Step Remedy That Fixes 99% of Grow Problems
Gain total harvest mastery by the end of today!
