Whether growing cannabis for commercial or personal use, timing is essential to ensure you get a high-quality and potent harvest. Having planted cannabis for some time, one of the most important things I have had to learn is how to tell when cannabis is ready for harvest.
Understanding the best time to harvest cannabis gives your plants enough time to mature and have compact and heavy buds. It also helps develop flavor, aroma, and potency.
With so many strains available to grow, they all have different development periods, and there is no universal timeline for when the buds are ready for harvest. The cannabis harvesting time can also vary depending on your planting method, growing conditions, plus the yield quality and quantity you want.
However, understanding the growing cycle and the plant’s changes has helped me know when to harvest marijuana plants over the years.
Cannabis Growth Stages
Whether you are growing your cannabis plants indoors or outdoors, understanding their growth stage helps you understand what they need for a better harvest.
It is essential to note that outdoor cannabis plants will take longer because they depend more on the natural growing season. However, with indoor plants, you can change the light spectrum and add nutrients to speed up growth.
The following are the four stages to look out for.
Seed germination stage
This stage happens between 7 and 14 days after planting your seeds when the seeds start sprouting and you can see some growth above the soil. The germination stage depends on the type of soil plus the growing conditions.
This is when the seeds begin opening, and the plant starts producing its first leaves. The leaves start as small and round, mostly called cotyledons, then progress to serrated leaflets.
They then develop into the digitated leaves we all know as cannabis leaves. This stage could last between two and three weeks.
During this stage, cannabis plants start establishing and growing stronger roots and storing energy to prepare for the flowering stage. This stage lasts between three and six weeks, but it can be shorter for indoor plants because you can adjust your grow lights to trigger early flowering.
You can do that by changing the color spectrum or changing to a 12/12 light cycle with 12 hours of light and 12 hours of darkness unless you have auto-flowering plants.
This is the last and most crucial stage to monitor because it tells a lot about when to harvest weed. It lasts 6-16 weeks, depending on the strain you plant. During the first five weeks, the plants usually start producing buds and flowers and use the rest of the time to ripen.
Cannabis indica and ruderalis have the shortest flowering stage and are usually ready in about six to eight weeks, with the longest being ready after around 12 weeks.
Some fast-maturing varieties include Maple leaf Indica, Northern Lights, Early Girl White Ryder, Lowryder, Hobbit, Red Dwarf, Speed Queen, Bruce Banner #3, and Superglue.
Sativa strains, which are tall and skinny, can take between 12 and 16 weeks to flower and fully mature for harvest. Some varieties with the longest flowering period include Durban Poison, Neville’s Haze, Chocolate Thai, Colombian Gold, and Malawi Gold.
Hybrid strains are a combination of tall, thin, and long-growing sativas and short, stout, and fast-growing indicas. They usually take around six to 12 weeks to fully mature.
To increase your plant’s bud production, you can prune the bottom leaves during the flowering stage to help the plant concentrate more energy producing buds.
How To Know When To Harvest Cannabis
There are several signs that I look at to determine the best cannabis harvesting time. While you can take time to observe the whole plant, the leaves, trichomes, and buds are the best indicators of a weed plant ready for harvest.
Trichomes are small resin glands on the buds that give them a dewy look and where the terpenes and cannabinoids are produced, giving different strains unique characteristics.
When the cannabis plants are in the flowering stage, the trichomes are usually clear and crystal-like, meaning the plant is still not mature and has not attained enough potency.
You will know it is the best time to harvest cannabis when the trichomes are cloudy white or amber. Cloudy white trichomes indicate that cannabinoid production is at its highest, while amber trichomes mean the THC/THCA in the plants has begun reducing, indicating more CBN in the flower.
The cloudy white trichomes mean the plant will give an uplifting and energizing effect, while amber trichomes mean it will give a sedative effect.
Therefore, many people love mixing the trichome colors, and the ratio depends on the effect you want your harvest to have. For the highest THC levels, the best cannabis harvesting time is when 70-80% of the trichomes are cloudy white. To determine the trichome color, you must have a magnifying glass.
Healthy cannabis plants usually have fan and vibrant green leaves. The best cannabis harvesting time is when the leaves start turning yellow or brown and curling or falling off.
Different cannabis strain buds have different shapes and densities, so when is cannabis ready to harvest when considering the buds? Buds ready to harvest are usually thicker and have darker pistils.
You will also notice that the buds stop becoming bigger, and the branches of the plant start hanging more because of the buds’ weight.
Pistils are small hair-like structures that are the female plant reproductive organs. During the flowering stage, the pistils are usually white, but they darken to a brown, red, or orange color when fully mature. The more the pistils that have changed color, the heavier and more potent the buds will be.
When 40% of the pistils are dark, the buds are ready to harvest because they have enough THC to give a high but have not reached the peak.
The best buds ready to harvest have darkened 50-60% of the pistils because they have the highest THC levels. However, if you wait for 80-90% of the pistils to darken, the THC has started turning to CBN.
How To Harvest Cannabis
Once you decide when to harvest marijuana, you can chop all your plants at once, especially if you have auto-flowering plants, or do it gradually. The best time to harvest is in the morning or before you turn your grow lights on.
Over the years I have planted cannabis, I usually harvest mine gradually. One main reason is that the buds on the upper branches ripen faster. In this case, I usually cut the main stalk halfway or cut off the upper branches individually.
This makes it easier for light to get through to the lower branches over the next week I leave them.
Harvesting in sections also helps manage the effort, time, and space I need to harvest and dry the produce.
After harvesting the buds on the lower branches, I usually cut the stalk to ground level or below, making it easier for a ‘no till’ or recycled organic matter planting season.
Is Flushing Necessary?
Growers who use organic growing methods don’t necessarily have to flush the cannabis plants. However, since I use chemical fertilizers, I usually flush mine to ensure no chemicals build up in the buds. The buds will have an unpleasant taste or harsh burn if not flushed.
Flushing is where you flush the plants and the growing medium with water for nearly two weeks. This way, they can release or use any chemicals and salts in the vascular system.
Drying And Curing
These are the last two processes after harvesting, but they also play a massive role in your weed’s taste, aroma, and potency.
After clipping and manicuring the weed, you should look for a conducive place to hang or spread it. I prefer hanging mine because it promotes airflow around the buds and prevents moisture accumulation on the buds’ bottom side, which happens when they are spread.
The drying process can take anywhere between a few days to weeks, depending on the plants’ initial moisture level and the drying area’s conditions. The harvest usually tastes better when dried slowly in a dark room with proper ventilation and regular to low humidity.
To know if my clippings have adequately dried, I usually try to break a small branch, and if it snaps, it is fully dry.
The next step is putting them into a jar, 80% full, closing the jars, and setting them in a dark room. Ensure to shake the buds daily and open the jars to let the buds ‘burp.’
Determining when to harvest cannabis plays a massive role in the amount of harvest you will get, plus its quality, potency, aroma, and taste. The time depends on the strains you grow, whether you grow them indoors or outdoors, plus the growing conditions.
You should look at the leaves, trichomes, and buds, but ensure you consult a pro-marijuana grower or experts from where you get your seeds. They will help you know how to get the best yields and offer additional tips on how to know when to harvest cannabis.