Nutrient, Water, and Light Considerations When Transplanting Marijuana Seedlings
If you’re planting in coco coir, a soilless medium, or hydroponics, only add cannabis nutrients at seedling strength, or 1/4 the regular strength, until your plants have grown a few sets of leaves. Then you can slowly start working your way up to full strength nutrient levels. With young marijuana seedlings, less is more.
In general, if you are growing in soil, your water pH (acidity level) should not be an issue. If growing hydroponically, water pH is very important and needs to be checked regularly. Some growers get lucky and happen to have water with the right pH, but if you’re noticing deficiencies and problems with your seedlings, definitely take the time to understand about the pH of you water and how it affects the plant’s overall health. Read more about pH and water here.
If you plan on growing indoors under high intensity grow lights (such as HPS or MH grow lights), you may want to start them out with less intense fluorescent grow lights or compact florescent bulbs (CFLs). Or just keep your high intensity grow lights several feet away at first, and slowly move lights closer as your seedlings gets older.
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 flourescent 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 hand 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.
Make sure to keep a close eye on your seedlings to ensure they don’t grow too close to the 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 (pale color, wilting or browning leaves or generally weak), try moving the lights further away and see if that helps.
Next: What to Look for in Healthy Marijuana Seedlings