Cannabis foxtailing is the effect seen when one calyx stacks on top of another forming a thin elongated “foxtail.” These are often just a calyx or two wide and an inch or two long. Some cannabis breeders have stabilized the foxtail trait for those that enjoy the unusual. But for most other strains, cannabis foxtails may represent lost yield potential. For many home growers, as well as commercial licensed growers, large, heavy-yielding blooms full of dense, THC-rich buds is the preferred goal. Learn why cannabis foxtails form and how to detect, prevent, and/or manage them.
What is foxtailing in cannabis plants?
Cannabis foxtailing causes your buds to take on an unusual, weird, and irregular growth pattern. Instead of the normal chunky buds you are used to, a cannabis foxtail is a long, thin structure caused by a small number of calyxes which grow in a stacked formation. Although the similarities with a real fox’s tail may be limited, the name has stuck.
What does foxtail weed look like?
As the pictures illustrate, foxtail weed may look unusual and intriguing. The buds will often be resinous and potent. And few can deny the attraction and interest in some of the more esoteric foxtail cannabis strains.
Foxtail weed is often seen in heirloom sativa strains. Many of the best cannabis seed companies hold archived genetics that produce this phenomenon.
But demand for seeds of foxtail strains has never been particularly high, mainly due to yield concerns. For that reason, there is limited interest in foxtail-prone strains. Indeed, many growers may feel somewhat alarmed if they see their cannabis buds start to foxtail and may wonder what the remedy is.
Is foxtailing in cannabis plants bad?
Many growers deliberately research their cannabis seeds, often favoring high THC strains with thick, heavy blooms and generous yields. It can feel like a disappointment if the promised branch-breaking harvests are replaced with gangly, slender foxtails.
Foxtailing cannabis may be a desired trait that you enjoy seeing, and your friends will often be impressed to see it. The “buds” may have normal potency levels and great flavor, but most growers prefer to see normal bud formation.
What causes cannabis buds to foxtail?
Cannabis foxtails is sometimes known as a second internode bloom. It may simply be the last “hurrah” from your plants as they approach harvest and squeeze out a few more buds. Yield concerns may be minimal, especially if the foxtails are forming on already generously proportioned blooms late in the flowering phase. In these circumstances there is little to worry about and you may just want to check that your grow room conditions are within the right limits and continue to allow your plants to reach harvest point.
But sometimes environmental conditions in the grow room itself may have strayed into sub-optimized territory. This can cause plant stress and with it comes the conditions which may cause your normally fat buds to start foxtailing. In these cases, swift action can limit the yield losses and return your plants to normal growth.
Genetics:
Normally your cannabis seed supplier will indicate if your preferred strain has been deliberately bred to foxtail. Very few commercial varieties are designed like this due to limited interest from growers. But you may see foxtailing especially on some sativa strains; this can happen with either feminized cannabis seeds or autoflower seeds.
Three of Dutch Passion’s sativa strains, Desfrán, Strawberry Cough, and Skywalker Haze may occasionally show foxtails, even in good grow conditions. This is simply a genetic trait, meaning there is nothing to worry about if you see the occasional foxtail.
Heat stress:
Heat stress is a known trigger for cannabis foxtailing. Cannabis grows well indoors when the “lights-on” temperatures are around 72–77°F (22–25°C). Exceed these temperatures and one of the effects you may see is increased numbers of cannabis foxtails. Those growing cannabis outdoors or in greenhouses may see the same effect.
Light stress:
If you have pushed your plants above the optical sweet spot in bloom you may also see cannabis foxtails appear. Often, light intensities above 1000 PPFD (without CO₂ supplementation) may be too much for some strains. The stress from light overload can induce cannabis foxtail formation.
Less experienced growers, or those who have recently invested in powerful LED grow lights, may be particularly at risk of this, as are growers who have lights too close to their crops. Yellowing leaves can also be a sign that they are suffering light stress. Combine light stress with cannabis genetics that may be predisposed to it and cannabis foxtailing may result.
Many serious growers use a light meter to map the light intensities in their grow room at different light hanging heights. Or they use data from the LED light supplier to determine the optical sweet spot for their plants.
How to fix foxtailing cannabis buds
Assuming that you haven’t deliberately grown a known stabilized foxtail strain, the main approach is to return grow room conditions to optimized conditions as soon as possible. Reduce heat, increase extraction, and reduce light intensity. Many LEDs have controllable intensity dials. If not, just raise the height of the light, increasing the distance to the canopy.
How to prevent foxtailing buds
You may want to avoid growing in the hottest seasons if you have seen cannabis crops foxtail previously in heat waves. Those that can afford it will add air conditioning to the grow room. This allows absolute temperature control in all conditions/seasons and will also allow yield and potency improvements as your plants bloom in optimized conditions.
Those that suspect light stress has contributed to previous cannabis foxtail problems may also want to check with their light manufacturer. Usually, the more competent suppliers will be able to offer accurate charts showing recommended coverage areas and PPFD levels at various hanging heights for different-sized grow rooms.
When to harvest foxtailing cannabis buds
Judge the harvest point as you normally would. Most look for the point when their trichomes are mostly cloudy and take the crop down at that point. Some growers enjoy early-harvested cannabis, with clear trichomes and a lively, energetic high. Others prefer a few red/amber trichomes, which may offer a heavier, “stonier” effect.
Dutch Passion’s foxtailing cannabis strains
None of the Dutch Passion strains have been stabilized deliberately to produce foxtail cannabis. Instead, all the strains should produce long, heavy blooms when grown well. But it’s also fair to add that just about any cannabis strain can express foxtail tendencies when the conditions are stressed, especially sativa strains or sativa-dominant phenotypes of a given strain.
Some pure sativa strains may express foxtailing in the buds—varieties like Desfrán, for example—no matter the circumstances. Skywalker Haze and Strawberry Cough are two other cannabis strains which may sometimes show foxtails, especially in hotter conditions.
Foxtails are equally likely whether you are growing from autoflowering cannabis seeds or photoperiod feminized seeds. Causes of cannabis foxtailing vary and may even include sub-surface root rot or damage. But more often, the primary cause of cannabis foxtails is heat stress and/or light stress. Avoid these and the chances are that foxtails won’t be a major headache in your next grow.