Growing your own bud takes a lot of time, effort, and patience. From germinating the seeds to finally harvesting the finished product, all of it takes a generous amount of work throughout quite a painstaking process.

If you are lucky, your buds will grow out how they should be: picture-perfect, in a conical shape, ready to be dried and consumed. But there are times when foxtails occur, which may add more work to the cultivation process and alter the aesthetic of your buds.

cannabis buds foxtailing due to heat or light stress


The cannabis plant features calyces, which are a potential spot for seeds to develop. Particularly for female plants, calyces grow in groups during the period of maturation when they soak up light. This presents an opportunity for foxtails to show up. Foxtails are essentially a bunch of calyces stacked on top of each other to comprise an oddly-shaped bud formation.

Buds that foxtail are not exactly detrimental, but they are not exactly beneficial either. The most glaring setback is that it breaks up the structure of the herb. Instead of growing into a rounder shape, it tends to sprout out in a more elongated way, ultimately leaving less of the plant for you to use. In addition, this process is a common indication that your plants are not properly ripening.

“Bad” foxtailing involves the occurrence of foxtails due to heat and/or light stress. This often manifests in calyces that form spires and make the bud look quite odd.

However, foxtailing is not always an abnormality. There are certain cannabis varieties that feature naturally-occurring foxtails, like in some Purple strains, or the Cole Train strain. This process is more common among sativa plants, specifically buds that were grown in tropical regions such as Colombia or Thailand.

cannabis foxtailing calyces


The first type of foxtailing deals with genetics. Some buds are genetically predisposed to this process. The foxtail on these kinds of herbs is more uniform and predominant throughout the plant.

This is considered “good foxtailing” since it is already in the bud’s nature. The process will inevitably take place, no matter what growing techniques are used. It is also worth noting that buds that undergo genetic foxtailing tend to have a higher THC content.

Another type of foxtailing is caused by heat or light stress. This process usually happens to those that grow their buds indoors. Plants that are placed too close to an LED or high-powered HPS light are at the highest risk.

Unlike genetic foxtailing, which is considered “good,” this kind is the opposite. In this circumstance, the foxtailing reaction indicates that the grower must move lights further away from plants or reduce daily light exposure. Foxtails forming from light overexposure do not display much damage, but in reality, chances of the herb losing potency after repeat light stress are high.

led, HID and non-cooler lights cannabis cultivation


As stated above, the cause of “bad” foxtailing is the bud’s prolonged exposure to heat and light. Common sense would, of course, dictate avoiding these occurrences, but there are other supporting methods as well.

One of them is to keep the grow room’s standard temperature at 23 degrees Celsius (74 degrees Fahrenheit) when the lights are on, then lower it 5-7 degrees cooler when the lights are off. You can do this by installing an air conditioner or venting capacity, or by going for cooled lights instead of HPS.

For the plant’s proximity to light, you can keep it at a safe distance of 24 inches under HID lights, and 30 inches under non-cooled lights. If you are using LED lights, you can go as close as 15 inches.

Another problem could be that sativa strains are more naturally suited to growing outdoors. But if you have no other choice but to cultivate indoors, be sure to limit light exposure to 11.5 hours in the span of an entire day. You can also feed it some B-52 vitamin to lower its stress levels. Allow as much space above and around the plant as possible.

With these simple steps, you could quite possibly save your yield and its potency from a stress overdose.

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