I’m about to start marijuana seed forecasting outdoors. I was hoping to use a sop-watt halogen lamp to grow them under. Is it okay to use these lights? I’m on a tight budget.
For the most part, the best indoor lamps for germination marijuana seeds are going to be metal halide (MH) and high pressure sodium (HPS) lights. Their light spectrums are good for vegetative growth, and they are also good for conserving energy. Their light intensity tends to promote sturdy stems and quick growth.
In the event that MH lights are outside of your budgetary range, you can use fluorescent tubes. Having an input of around 40 watts per square foot would assure optimal growth. To achieve that, you’ll need about four tubes in a one-foot width. The tube’s spectrum is also of great importance. A cool-white or natural-white tube with a Kelvin of between 4,000 and 5,000 is a decent selection. It might be more convenient for a startup garden to use inexpensive screw-in compact fluorescent lamps rather than actual tubes.
Fluorescent tubes that are designed for reptile tanks have around 7% UV light which desensitizes your plants to sunlight. You can use these tubes instead of standard fluorescents during the entire germination process to facilitate the plants’ eventual move outdoors.
Instead of giving the marijuana seedlings a continuous light source, they need to be on a light cycle of 17 to 18 hours of brightness and 6 to 7 hours of darkness for each day. With the use of a light cycle, you effectively prevent the plants from being “shocked” when they’re transplanted and start to experience periods of darkness. Indeed, if grown under permanent light, they could start flowering when placed outdoors.
Prior to transplanting the cannabis plants in full view of the sunlight, they need to adapt to the outdoor environment. Ultraviolet light, which is the major source of sunburns in humans, can also cause burns to plant leaves that have yet to acclimate. To avoid this, place the plants in the shade at first and then gradually work your way up to full sun over about 7 days. Many of the indoor leaves might still die, but the new growth will be healthy.