CFL bulbs (twisty/spiral bulbs as pictured to the right) are a great source of light for young marijuana seedlings. CFLs provide the right types of light for seedlings CFLs are extremely cheap to buy CFLs are easy on your electric bill CFLs can be found almost anywhere, at your local hardware store, supermart, grocery store, or online. Keep CFLs or fluorescent lights about 6 inches away from your seedlings. Place your hand where the leaves are to make sure it doesn’t feel too hot.
If it’s hot for your after 10 seconds, it’s too hot for your plants. Once your seedlings have developed their first two sets of leaves, then you can move these lights as close as 2 inches away as long as the lights aren’t too hot. Remember: If grow lights feels too hot to your hand after 10 seconds, they’re too hot for your marijuana seedlings. Make sure to keep a close eye on your seedlings to ensure they don’t grow too close to the grow lights and burn themselves. Seedlings can grow fast, and many growers have been surprised to find plants have actually grown into the light overnight. If new seedlings are showing signs of stress, try moving the lights further away and see if that helps. Once marijuana seedlings are about fourteen days old, they’re ready to start being treated as if they’re in the vegetative stage. Seedling Two round cotyledon leaves, then two “real” (serrated) single-finger cannabis leaves.
Next, the single-finger leaves expand, and the next set is usually 3-finger leaves. Next, the cannabis plant will start making 5-finger leaves. Finally, most cannabis plants stop at 7-finger leaves. If you look closely at the above plant, you can see that some of the newer leaves on this plant actually have 9 fingers. It is normal for there to be some variation between leaves – some plants will grow leaves with 11 or even 13 fingers. But the above guide will give you a general idea of what to expect. Once your cannabis seedling is about fourteen days old, it’s ready to start being treated as if in the vegetative stage. Make sure you learn about plant training techniques to make the most of your time in the vegetative stage! My seed is growing upside down with the roots up; what do I do? As long as the roots of a cannabis seedling are able to grow down, they will. Seedlings can sense the difference between up and down. So how come sometimes it looks like a cannabis plant is growing with its roots pointing up? When the seed end is still bent down, all you see is a U-shaped stem/root. Cannabis seeds can look a bit different when germinating. When in doubt, always wait a few days to see if leaves appear before you try to interfere. Sometimes the stem of a brand new cannabis seedling can look like the roots growing out the top. But if you wait and watch, you’ll see that it’s all part of the plan. Sometimes you’ll see what appears to be roots emerging from your cannabis seed, but this is actually the stem. The stem pushes the seed and leaves up, and the main taproot is currently burrowing down to support the seedling. As the seedling emerges you’ll be able to see the leaves (sometimes it will still have the seed stuck on the first leaves, like in the picture above). The cotyledons (first, round leaves) unfurl, and then the regular cannabis leaves between to grow. Here’s another view of that same seedling from above.
Even though it may have looked a bit weird at first, this seedling is completely normal and will grow just fine from now on.
When growing cannabis plants in a container, you have to choose the size of your pot.