How To Prevent Stretchy Cannabis Seedlings

Are your cannabis seedlings growing tall, with long stems and few leaves? This is a common problem that, when not addressed quickly, can kill your seedlings. Luckily, it’s easy to deal with.

WHAT CAUSES STRETCHY CANNABIS SEEDLINGS?

Cannabis seedlings develop long, stretchy stems when they’re lacking light. In an attempt to get more light and keep growing, the seedlings put all their energy into developing a long stem rather than foliage. This is a natural survival mechanism that, in nature, helps the plant grow taller than others around it in order to soak up as much light as possible.

Stretchy seedlings are a really common problem among first-time growers. There’s a lot of information online encouraging growers to keep their seeds in the dark after germinating and planting them to encourage root growth. Unfortunately, this usually just starves the seedlings of light and immediately encourages them to stretch.

Another common cause of stretchy seedlings is using the wrong grow lights. Many growers pop their seedlings under their regular grow lights at a distance to compensate for the light’s high wattage. As a result, the seedlings end up lacking light and stretch.

HOW TO FIX STRETCHY SEEDLINGS

If you notice your seedlings growing long and stretchy, you’ll want to act quickly. When caught early, you can usually avoid causing your plants any serious harm. If you’re too late, however, your plants may die from the lack of light.

First, you’ll want to help your plants stand upright. To do so, tie them to a wooden skewer or, better yet, try replanting them in deeper soil, leaving only the top 3–4cm of stem sticking out of the soil.

Next, you’ll want to address your lighting situation. The best solution for growing healthy cannabis seedlings is to position 40W compact fluorescent lamps (CFLs) roughly 5–7cm from the tops of your seedlings. One lamp usually gives off enough light to support around 3–4 seedlings. Just keep an eye on your seedlings to ensure they don’t get too close to the light source. This is a recipe for light/heat stress.

After installing your lights, your seedlings should start developing thicker, bushier foliage. After a few weeks, they should develop some full-fingered leaves, at which point you can switch to stronger lights to support your plants during their vegetative growth phase.

EXTRA TIPS FOR HEALTHY SEEDLINGS

• Don’t overwater: Droopy, yellow leaves and limp stems are a sign you’re watering your seedlings too much. Remember, seedlings have very small roots that’ll drown in overwatered soil. Your soil should be damp, but never soaked.

• Too much heat/light: Seedlings are very sensitive, and too much light can be just as damaging as too little. Burnt, crinkled, or upward-folded leaves are classic signs that your seedlings are receiving too much light/heat. Follow the lighting instructions we mentioned above to ensure your little ladies don’t suffer from light stress.

• Avoid nutrient burn: Seedlings can easily die if given too many nutrients. If in doubt, avoid feeding your seedlings until they’ve entered the vegetative growth phase and developed a few full-fingered leaves.

SAY GOODBYE TO LONG, STRETCHY WEED SEEDLINGS

A lack of adequate light is the #1 cause of long, stretchy weed seedlings. Once you've germinated your seeds, make sure your seedlings get plenty of low-wattage light to support steady growth and healthy foliage. By following this tip, and the others mentioned in this article, you can achieve healthy seedlings of a desirable size—every time!