How much light to give cannabis seedlings?

Light is an important part of plant growth. Insufficient lighting will seriously hinder the growth ability of plants, and most importantly, maximize the yield of flower buds. However, too much light can cause significant burns (color changes), which can damage the plant and worsen its overall health (and therefore produce buds).

How much light you should give your plant and how it should be distributed usually depends on many factors. And the light intensity required by different growth stages of marijuana is also different. When choosing plant grow lights, you should carefully consider the size of the crown area, the Watts required per square foot, and how to optimize the light.

Suitable conditions are needed for seed germination. Need the right amount of light, the right temperature and the right amount of moisture. If you provide the conditions they want, the change of successful germination will soar. If you don’t provide the ideal conditions, your chances of success will plummet.

When the seed germinates, the seam of the seed will crack, and the white tendril will pierce it within a few hours after the crack. The tendril grows rapidly and moves downward until it is deep enough to support the rest of the plant (i.e. stem and seed shell). Hemp seeds do not need light to germinate. In fact, they need darkness, and once they germinate, they will need a lot of light – 18 hours a day to be exact.

So how much light does marijuana seedlings need?

You can put the seedlings under HPS or MH lights, but it is more cost-effective to use LED or fluorescent lights. Metal halide lamps are more suitable for seedlings than HPS lamps because they need colder light, and blue light is more than red light.

When using HID lighting (usually metal halide lamps), the seedlings should be kept at least 50 cm away from the bulb.

Compact fluorescent lamps (usually more than 100W) shall be used, and the distance between the top of seedlings and the bulb shall be about 15cm.

If ordinary fluorescent tubes (18-36w) are used, the seedlings can be kept within a few centimeters from the light source.

Hemp seedlings grown under light should always get a breeze from the swinging fan (the lowest set of small household fans is good), because continuous gentle exercise will significantly enhance their stems.

Generally, Plants at seedling stage need 200-300 umol / s.

Plants in the vegetation stage should receive light between 306 and 617 umol / s when exposed to 18 hours of light.

Flowering plants received 12 hours of light and received light between 460 and 925 umol / s.