What you Need to Know about Growing Weed Indoors

Growing Marijuana Tip: Light Schedule for Seedlings

It is frustrating for a novice in marijuana growing to start seeds indoors and the seedlings are weak and spindly. Growing indoors have to mean that the natural light source is very limited and having your grow box hanging on your windowsill is not a very good idea. It is imperative to determine the right light schedule for seedlings to have a more productive yield.

The seedling stage starts when the shoots begin to develop in the first couple of real leaves. Unlike other types of plants which have oval-shaped leaves, the marijuana seedling already looks similar to an actual marijuana leaf sporting the serrated edge but at this point, it has only one finger. Then the succeeding leaves that will appear have 3 fingers and as the seedling develop,s it will look more like the adult plant until it finally has a set of 5 to 7 finger leaves.

End of the Seedling Stage


Expert growers observed that as the numbers of finger leaf are nearly the same as an adult plant signifies that the seedling stage is about to end, and the plant is ready to the next stage which is the vegetative phase. Other growers check the thickness of the stem once it reaches a certain thickness indicating that the seedling stage is done or if the plant has 3 to 4 leaf nodes also means that the seedling stage is over.

Points to Remember

The span of time spent on the seedling stage varies on the growing location, whether it is indoors or outdoors. For indoor growing, it would take about 2 to 3 weeks for cannabis plants to experience the seedling stage, while outdoor growing, it may extend up to 6 weeks for the seedling period.

While you are patiently waiting for your plant to mature while it is in the seedling phase, the plant is taking its time and energy to develop a root system, getting ready to feed on the nutrients needed to fully grow into a healthy and mature marijuana plant. Learning the light schedule for seedlings will help you provide the best care for your cannabis plants.

Tips on Handling Your Marijuana Seedlings

You can put a small fan with a weak but consistent air blowing over where your seedlings are. The airflow can help in preventing the development of mold and this will also give the seedlings additional energy to grow stronger and have a better structure.


Seedlings are very delicate and may have a hard time adapting if they are transplanted too early. The ideal time to transplant seedlings is when you can see that they have fully developed root systems. You’ll notice roots coming out. In transplanting the seedlings, avoid causing damage to the still small and fragile plant.

Light Schedule for Seedlings

Seedlings do not need too much light at this point in order to grow. If the seedlings are exposed to a very intense light, this could do more damage than help the seedlings in this early stage.

Many growers use fluorescent light tubes. This are relatively have weak lights and are optimally perfect just for the purpose of growing seedlings. The weak fluorescent light is suggested to be placed just 5 cm above the marijuana seedlings.

Importance of Light in Marijuana Growing

If other types of grow light were used for the marijuana seedlings, like the HID lights, be reminded that this kind of lights produces a great amount of heat. Then additional care should be practiced and the distance from the seedlings should be about 80 cm above the seedlings.

Slowly get the seedling accustomed to HID light and also lower the light few cm each day until the distance is just around 40 to 60 cm dependent wattage. A simple heat test can be done by holding your hands under the light and If you feel too hot for on your hands surely this will be the same for the seedlings.

For optimum growth of the seedling, you can start with a “cold” spectrum this will also be helpful in the early vegetative growth. These lamps have bluer spectrum than the lamps used in flowering lamps, which have more of the red spectrum.

The best and perfect light cycles for seedlings is the most commonly used is the 18/6 light schedule. This means 18 hours of light per day and 6 hour darkness period but some uses the 20/4 or even 24/0 light schedule. As a cannabis grower, you can experiment which would best for your plants to give you the highest results.

Nutrition for the Seedlings

For a very young seedling which just sprouted, it really don’t need much nutrients. Beginners should do their homework to avoid overfeeding their cannabis plants. Supplying seedlings too much nutrients can do more harm than good at this stage. Let the seedlings look for the nutrients themselves and time to grow its root system

Guide in Giving Nutrients of Marijuana Seedlings

Use only clean or preferably distilled water with a pH level of 6.5-7 no nutrients added yet After 1 or 2 weeks, then you can already begin introducing nutrients. just do not overfeed them they are still highly sensitive. At this stage only use half of the recommended amount of nutrients, if not you might end up killing your seedlings. For seedlings, less is better.

Many commercialized potting have nutrients mixed in them. So this is not recommended, you can use light potting mixes or rock wool or even better you can make your own mixes with perlite.

Final Thoughts

In growing marijuana seedlings to be strong and healthy, it is really vital to expose them in a proper lighting right from the get go. Light is an important factor of getting a seedling healthy as well as giving them a good head start. Taking care of seedlings serves as your training ground and it makes everything easier in the next stages to come.

It is far more difficult to handle and manage small and delicate seedlings than matured plants. It will test your patience and how you treat this fragile seedlings will define your treatment to them once they have been fully matured to flower. The process does not start with your plant in the vegetative stage, it starts from germination to harvest so your responsibility would start from seed selection until the buds are smoked. Now, you have just learned the importance of knowing the right light schedule for seedlings.

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