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light hours for growing weed

Light hours for growing weed

After 2-3 weeks of the 12-12 light schedule, most cannabis plants will show the first signs of their gender (they either are a female plant which starts growing buds, YAY! or they are a male plant which start growing balls/pollen sacs, NO!).

However, when growing weed indoors, a marijuana gardener will have to fool their plants into "thinking" winter is coming to induce flowering and kickstart the creation of buds.

So all strains of cannabis that respond to light in this way (where the light period effects what stage they're in) are called "Photoperiod dependent" strains.

If you're growing a cannabis plant grown from a random seed ("bagseed"), unless you somehow have an auto-flowering seed, you will need to understand about cannabis life stages and how they are affected by light periods.

Photoperiod dependent strains vs. auto-flowering strains

Light hours for growing weed

The key to growing indoor cannabis is mimicking what happens in nature. When grown outdoors, cannabis starts to produce flowers (buds) when the days begin to become shorter and they receive at least 12 hours of total darkness. All that’s needed to do this is to switch your light schedule from 18-24 hours of “sunlight” each day to 12 hours of light and 12 hours of darkness.

It’s important to keep in mind however that it’s not just your light schedule during veg that will ensure a bigger yield come harvest. Some strains, such as Jack Herer and Northern Lights , simply produce more weed. And if you’re growing inside and don’t have high ceilings and a well-maintained grow room, your plants aren’t likely to get as big as you’d like them to be. Big plants with big yields need plenty of space to grow.

Being able to manipulate a plant’s light schedule makes it possible to achieve higher yields when it comes time to harvest. When plants are in the vegetative stage, the more light they receive the larger they will grow.

Many growers will start their grow indoors under lights before moving their plants outside to grow naturally under the sun. Starting seeds or cutting clones in March or April and keeping them under 18-24 hours of light until they’re moved outside in early May or June is common.

Light Cycle for Indoor Flowering Period

Even when growing outdoors, many growers will start their plants inside to ensure they can grow as large as possible. When in veg, plants should be kept under grow lights for a minimum of 18 hours (commonly known as 18/6). Some growers will keep plants under 24 hours of light during this time (known as 24/0) to allow their plants to grow as big as possible.

If you’re growing outdoors, keep them inside on an 18/6 or 24/0 light schedule until all danger of frost and freezing temperatures are over and you can safely take them outside. Once they’re outside all you need to do is let nature do its thing as the sun rises and sets each day on its own.

Marijuana plants don’t begin to flower until they begin to receive 12 hours of uninterrupted darkness. Until then, they’ll continue to stay in the vegetative stage. You can essentially keep your plants in veg forever as long as they’re receiving 13 hours or more of light each day.

Indoor Vegetative Light Period for Maximum Yields

There are two major cycles of growing marijuana. These are the vegetative stage (when plants are growing) and the flowering stage (when plants produce flowers or buds).

Typically, the goal of growing weed is to have a large yield when it comes time to harvest. Whether you’re growing indoor or outdoor herb, light is one of the essential aspects of your grow. The light your plants get throughout their entire life cycle will have a tremendous impact on how much they weed they produce.