How To Tell When To Harvest Cannabis Growing In A Greenhouse

If you don’t know how to tell when to harvest cannabis growing in a greenhouse, look for visual signs. Much like any plant in the greenhouse, timing is crucial in harvesting cannabis. Otherwise, the effort you’ve exerted during growing indoors will go to waste. 

Why do growers have to know when to harvest cannabis correctly? A common mistake of new cultivators is doing this too early. The drawbacks you’ll get are that the THC in your plants will not be as potent, but besides reduced potency, the yield will also be underwhelming. 

How To Tell When To Harvest Cannabis Growing In A Greenhouse

On the other hand, harvesting too late will degrade the THC in the plants. Overall, harvesting cannabis at the right time will ensure quality yield. This part of the greenhouse cultivation is probably the most rewarding, so why do it without careful planning? 

Guide On How To Tell When To Harvest Cannabis Growing In A Greenhouse

If you want to know the exact date to harvest cannabis in the greenhouse, it will depend on the strains. Indica will flower for eight weeks, while sativa takes ten weeks of flowering. Both strains will be ready after these periods, while auto-flowering strains are ready ten weeks after seedling. 

However, the emphasis is necessary on the fact that these dates are guidelines only. These numbers will help you estimate and assume when you can harvest cannabis in the greenhouse. The best way to tell that you can reap is by looking at visual signs. 


Visual signs that cannabis is ready for harvest



Cannabis is ready for harvest when the trichomes turn milky white. A good sign that you’re harvesting too early is when they are clear instead of white. If you don’t know what trichomes are, they are the glands on the flowers and leaves. 

Therefore, you will need a magnifying device to check for this part of the plant. As cannabis matures, you can inspect how the trichomes change. For example, they look like crystals when your plant is just starting to flower. 

As time goes on, trichomes will look cloudy. However, do note that flowers are still not ready when trichomes are only half cloudy. When trichomes are mostly opaque, this signifies a high THC level, which is ideal for harvest. 

Remember that cloudy color will produce psychoactive effects, while trichomes that are amber will produce a narcotic high. 



A part of the cannabis plant that wouldn’t need a magnifying object is its leaves. When the fan leaves turn yellow, this can mean that you can start harvesting. Note that the fan leaves are the large and broad leaves on the plant. 

Don’t be confused and think that you can harvest during the vegetative phase. In some cases, the plant can show yellow leaves at this time because of nutritional deficiencies. However, harvest time is getting close when the plant has many flowers, and the fan leaves turn yellow. 



The hair-like parts on the flowers are the pistils of your cannabis plant. When they run red, it indicates that you can start snipping the flowers. You’ll also notice a change in their color as the plant matures.

For example, pistils start as white and turn red, brown, or orange until they are ready for harvest. Do not harvest when most pistils are still white. You want to collect when around 50% of them are red, which indicates the THC levels are also higher. 

Therefore, the more pistils have changed colors, and the THC levels will also be at maximum and cause more physical high. 


How To Harvest Cannabis In The Greenhouse



It’s best to cut one plant at a time from the base. You have the option to harvest them as whole plants or per branches. Please start with the largest leaves so that it’ll be more comfortable to trim the buds. 



You can trim cannabis either by dry or wet trimming. The former is best if you have full control over the humidity level, and you want to preserve the smell and taste, while wet trimming is best if the humidity level in the drying room is very high. Wet trimming also improves air circulation, which prevents the risk of fungal diseases.



For drying, tie the leaves at the base of the main stem in an upside-down direction. It will take around 15 days for the buds to be dry. To help with the process, maintain the room dark, and monitor the temperature at 64.4 to 73.4°F.

Afterward, you can improve the quality of the flowers by curing in an airtight glass jar. You will let them breathe for 10 minutes for the first three weeks. Maintain the storage room at 68°F and 50 to 55% humidity. 

Ventilation stops at the 6th month, and the flavor and aroma will get milder in the 8th month. 



More than marking your calendars for the expected harvest date, growers must know a more reliable way to indicate harvest. How to tell when to harvest cannabis growing in a greenhouse? Use both your naked eye and a magnifying tool. 

The trichomes, leaves, and pistils are essential parts of the plant that can give you telltale signs that it’s time to harvest cannabis. Growing cannabis in the greenhouse already helps in ensuring quality and high yield. But harvesting at the right time will also affect your output. 


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