How Long Does Weed Take to Grow: 4 Affecting Factors

Growing weed is a bit like waiting for a big surprise—you know it’ll be worth it, but the timing can keep you guessing. From cannabis seed to harvest-ready buds, the timeline depends on factors like strain, growing conditions, and care. Knowing what affects each stage of growth helps you plan, avoid surprises, and get the best results.

Key Takeaways

• Cannabis growth time varies by strain, environment, and cultivation method.
• Indoor setups allow greater control over light, climate, and yield.
• Key factors include genetics, nutrients, watering, and ventilation.
• Growth stages range from germination to harvest, each with specific needs.
• Training techniques can optimize space and bud production.

How Long Does It Take for Weed to Grow?

Knowing how long it takes to grow weed can be tricky, because the time from seed to harvest can vary from as little as 8 weeks to as long as 8 months.

Factors like your cannabis strain, whether you grow weed indoors or outdoors, and how you manage each stage of cannabis growth will determine the exact timeline. Indoor grows often finish faster, while a marijuana plant grown outdoors may take longer but can yield more.

If you’ve ever wondered why there’s such a big gap in how long it takes to grow marijuana, the answer is that cannabis cultivation is more than just planting a seed and waiting. From seed germination to the flowering stage and finally being ready for harvest, the time it takes to grow cannabis depends on your grow space, light cycles, and how you care for your plants.

Let’s break down the main factors that affect the time to harvest:

Cannabis Strain

The strain you choose has one of the biggest impacts on how long it will take your plant to grow. Autoflowering cannabis strains are quick finishers, often going from seed to harvest in just 2–3 months from seed. They skip the need for strict light control and move through the vegetative stage into flowering on their own, making them great if you want your plant to finish quickly.

Photoperiod strains, however, require you to control when a plant flowers—usually with 12 hours of light per day—and may take 4–8 months from seed to harvest. These traditional cannabis varieties typically grow larger and produce more buds, rewarding patient growers with higher yields.

Growing Environment

Your growing environment can speed up or slow down plant growth. Growing cannabis indoors gives you control over temperature, humidity, and hours of light, so you can manage vegetative growth and the flowering stage precisely.

This often shortens the time needed to grow weed indoors compared to growing outdoors, where plants will start and finish based on the seasons. Outdoor cannabis may still take longer, but the extra time can mean bigger weed plants and more buds at harvest.

Light Cycles

Light is crucial in determining how long it takes for a marijuana plant to flower. Photoperiod cannabis strains need 18 hours of light during vegetative growth, then 12 hours of light to trigger flowering. Properly timing this change is key to improving plant growth and controlling your plant from seed to harvest.

Autoflowers, on the other hand, will continue to grow and flower on their own schedule, meaning you can provide more light hours to encourage faster growth and bigger yields.

Care and Cultivation Techniques

The time it takes to grow a cannabis plant also depends on how well you care for it. Feeding schedules, pruning, training, and even recording a grow journal can all impact growth speed and quality. Techniques like low-stress training, topping, and defoliation help light reach all parts of the plant so buds grow evenly.

Healthy plants with good airflow, proper watering, and the right nutrients will typically grow faster and produce more resin-rich flowers when plants are ready for harvest.

Expert Tips for Growing Cannabis

Growing cannabis can be as simple or as advanced as you make it, but a few smart techniques can make a huge difference in your harvest. Here are some expert tips to help you get the most out of your grow.

• Choose the right strain for your goals – Autoflowers are great for quick harvests, while photoperiod strains offer more control over plant size and yield. Pick a strain that matches your grow space, timeline, and desired effects.
• Control your environment – Keep temperature, humidity, and airflow within ideal ranges for each growth stage. Small fluctuations are fine, but big swings can stress your plants and slow growth.
• Dial in your light setup – Use high-quality grow lights and adjust their height as your plants grow. Too close can cause light burn, while too far reduces growth and bud development.
• Feed wisely – Follow a balanced nutrient schedule, but don’t overdo it. Overfeeding can cause nutrient burn, while underfeeding slows plant growth and lowers yields.
• Train your plants – Techniques like low-stress training (LST), topping, or scrogging help maximize light exposure and encourage even bud development across the plant.
• Watch your water – Overwatering is one of the most common mistakes. Let the top layer of soil dry out between waterings, and make sure your pots have good drainage.
• Be patient and observe – Every cannabis plant grows a little differently. Watch for signs of stress or nutrient issues, and adjust your care accordingly rather than rushing the process.

Final Thoughts

Growing cannabis takes patience, attention, and a willingness to adapt along the way. While the time from seed to harvest can vary widely, knowing what influences each stage—and applying the right techniques—can make all the difference in your results.

If you’re ready to take the next step, you might enjoy learning our step-by-step cannabis growing guide to help you get started with confidence.

Frequently Asked Questions

Can I grow cannabis year-round?

Yes, but it depends on your setup. Indoor cannabis grows can run year-round since you control the light, temperature, and humidity. Outdoor cannabis grows are tied to the seasons, which means you’ll usually get one main harvest per year unless you live in a warm, sunny climate that allows multiple planting cycles.

How many times can I harvest from one cannabis plant?

Cannabis plants naturally complete one life cycle and then die, so you typically get one harvest per plant. However, some advanced growers use a method called “re-vegging,” where they keep part of the plant alive after harvest to encourage new growth for a second yield. This requires careful handling and is best for experienced growers.

What’s the best soil for growing cannabis?

Cannabis thrives in well-aerated, nutrient-rich soil with good drainage. Many growers use a mix of organic compost, perlite, and coco coir to create the ideal balance of water retention and airflow. The right soil can help prevent root rot and encourage healthy plant growth.

How much space do I need to grow cannabis indoors?

The space you need depends on how many plants you want to grow and their expected size. A single cannabis plant can fit in a small grow tent (about 2x2 feet), while multiple plants or larger strains may need a tent or grow room that’s 4x4 feet or more. Remember to factor in room for lights, fans, and ventilation.

Is it better to grow cannabis from seeds or clones?

Both have pros and cons. Growing from cannabis seeds allows you to choose from a wide variety of strains and ensures a fresh start with no pests or diseases. Clones, which are cuttings from a mature plant, give you a genetic copy of a known strain and can skip the germination stage, speeding up the process. Your choice depends on your priorities for time, variety, and certainty.