Ultimate Marijuana Indoor Grow Calendar

Plan every step of your indoor, soil-based growing process with this ultimate marijuana indoor grow calendar! Avoid the guesswork and reference this week-by-week roadmap from the moment you plant your seed to harvest.

Our indoor grow calendar serves as an excellent foundation for beginners to establish a routine with their cannabis plants. Adapt the calendar to meet your exact specifications as you develop your growing techniques. If you follow our weekly schedule, you should have a successful harvest!

Marijuana Indoor Grow Calendar

Vegetative Stage

After your plants have been fully germinated or the clones have taken root, you can begin the vegetative stage. During this stage, your plants will be focused on growing their stems. Generally, the vegetative stage can take up to four weeks.

Optimal indoor garden conditions during the vegetative stage:

• Light:
  • 18-14 hours of light
  • 6500 K
  • CMH or LED bulb
• RH%: 60-70%
• Nutrients:
  • High Nitrogen
  • Minimal Phosphorus
  • Low Potassium
• CO2: 1250-1500 ppm
• Temperature:
  • Standard: 72º-77ºF (22º-25ºC)
  • w/CO2: 82º-84º
  • Root zone: 65º-70ºF (18º-21ºC)

Week 1

During the first week of the vegetative stage, you will be allowing the cannabis plants to get acclimated to the light. If using multiple lights, use only about half of them and place them about twice the recommended distance (about 40 inches above your plants).

When watering, allow the water to flow from the bottom, a tray can be used. Only water them when the water is completely gone. If necessary, you may spray your plants with water to keep the humidity up. Ideally, you will have started with pre-fertilized soil, so no additional fertilizer is necessary.

Week 2

During the second week of the vegetative stage, you can begin to turn on all of the lights you will be using. You can also bring the lights closer to the canopy (about 20 inches above the plants). Just make sure your plants will not get burned.

Begin to water your plants from below using a tray. Roots should be able to absorb the water from the bottom of the container. Add a fan into your grow room on the lowest setting to improve airflow and strengthen the stems.

Week 3 and 4

Vegetative stages can last between four to eight weeks. The longer you leave the plant in the vegetative stage, the more it will grow during the flowering stage.

During the final weeks of the vegetative stage, your plants will begin to get ready to enter the flowering stage. Male plants will develop pollen sacs between their nodes while female plants grow white pistils. Only female plants grow flower buds.

Before switching from your vegetative to your flowering stage, give your plants 24 to 36 hours of full darkness and then begin the 12-12 light cycle. Avoid any light leaks during this time. If any light enters during this period of darkness, it can prevent the triggering of the flowering.

Flowering Stage

The next stage is the flowering stage. During the flowering stage, cannabis plants can nearly double in size compared to their vegetative height. During this time, plants will focus their growth on flower buds and resin production.

While following an indoor grow calendar you will want to also have optimal indoor garden conditions during the flowering stage. These include:

• Light:
  • 12 hours of light
  • 2700 K
  • HPS or LED bulb
• RH%: 45% (+/-5%)
• Nutrients:
  • Low Nitrogen
  • High Phosphorus
  • Medium Potassium
• CO2: None
• Temperature: 75ºF (24ºC) +/- 2º

Week 1

For plants that are getting too tall, you can install a trellis netting to create an even canopy for better light distribution. Make sure to work the overgrown branches through the trellis net to maintain an even canopy.

You may need to start watering your plants more often due to their fast growth. Make sure to prune off any leaves and small branches on the bottom third of the plant to improve air circulation and focus the growth on the top buds that get the most light.

Week 2

As your flowering begins to ramp up, you will need to water your plants more frequently as they get taller and your roots become bigger. However, do not overwater, which can lead to nutrient disorders.

This will also be the last week you should prune your crop. Since pruning can stress out a plant, you want to prune before the flowering begins to avoid lowering your yield and quality of buds.

Week 3

By this point, your plant will have grown considerably compared to the growth that happened during the vegetative stage. Cannabis buds will begin to take shape. The plant will require the most amount of water. You can keep your soil damp but avoid overwatering.

Week 4

You will really see your flowers grow and the aroma develop. You can start thinking about flushing your plants to remove the excess nutrients and salts. You can do a 24-hour flushing process without nutrients. After 24 hours, you can continue the normal feeding schedule.

Week 5 and 6

From this point forward, you will simply need to keep regular feedings and a sanitized growing space. You will see your cannabis plants grow bigger and the buds grow fatter. During week five, the flowers will start to get bigger. Make sure to prune off any damaged leaves or new growths to focus on bud growth.

Week 7

During week seven, you can begin the flushing stage by feeding your plants only fresh water until harvest. As your plants mature, you want to remove as much of the nutrients from the crop to improve its aroma, flavor, and overall quality.

Because of the flush, you may notice your leaves begin to turn yellow and wither away while your flower buds get all the focus and get bigger. This is normal and is a symptom of nitrogen deficiency, a normal part of the flowering stage during the flushing process.

Week 8

During the last week of the flowering stage, you will be preparing for harvest. However, strain growth varies by genetics. Some strains may need longer to flower than others. Flowering can go up to 12 weeks or more, depending on genetics.

At this stage, you will be flushing the rest of the nutrients from your crop and preparing for the next crop. Generally, you will have about 1 to 2 weeks where you can choose to harvest your plants, depending on your preference. Check out our guide on the right time to harvest.

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Growing cannabis from the comfort of your home is easier than ever.  There are also smart grow apps that track nutrients, watering, and more if you're more tech-inclined.

Cannabis Training University provides a complete education on the basics of cannabis cultivation and advanced techniques.

Enroll today and learn how to start growing marijuana indoors!