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Everything You Need To Know About Pistils On Cannabis

Published : Jan 23, 2019
Categories : Cannabis cultivation

If you have noticed several long, hair-like growths on your cannabis plant, then you are looking at pistils. A highly important part of cannabis anatomy, correctly identifying pistils is a must-have skill for any grower. If not, you could end up missing out on those all-important buds. Keep reading to find out more.

CANNABIS ANATOMY RECAP

To appreciate the importance of pistils, we first need to do a quick bit of cannabis growing 101. In recapping the core principles of marijuana growing, and the different parts of male and female plant anatomy, the purpose of pistils is easier to understand.

Cannabis plants can be three different sexes: male, female, and intersex (hermaphrodite). Most of the time, growers will want only female cannabis plants as these are the ones that produce smokable buds. If you are growing cannabis with the goal to produce seeds, however, then you will need both a female and male plant in order for the female to be pollinated. Moreover, from this anonymous sample of new seeds, there is no way to definitively determine the sex of each specimen until the plants reach the pre-flowering phase midway through veg.

WHAT IS A PISTIL?

Male plants don’t produce flowers; instead, they develop pollen sacks that, when mature, burst, spreading their pollen to female plants and fertilising them. For this to happen, the pollen has to come into contact with pistils. Also referred to as “stigmas”, they protrude from the calyx of a female plant.

The calyx has two functions depending on the circumstances. If a feminized plant is left to its own devices, the calyx will begin flowering and put its energy into developing buds. If, on the other hand, the pistil comes into contact with pollen, then the calyx becomes the ovary and will put its energy into producing seeds, not buds. The objective for most cultivators will be to produce seedless feminized cannabis plants, or “sensimilla”. These are the cannabis plants that provide us with large, resinous buds.

WHY ARE PISTILS IMPORTANT?

The importance of pistils is two-fold. First, they help us identify the sex of our cannabis plants, and second, they can be used to indicate when we should harvest during the flowering stage.

• Sexing Plants Via The Pistils

If we begin with the sexing of a cannabis plant, the technique is relatively simple. If pistils are present post-germination, then you have a female plant. If they are not, then the plant is male and should be removed immediately to prevent other plants being pollinated.

If we split cannabis plants into autoflowering and photoperiod categories, the former is the easiest to sex because flowering is rapid, and multiple pistils tend to appear at once. The latter can prove slightly more complex. Not because the pistils are necessarily tricky to spot, but because they can appear at different times depending on the genetics of the strain.

Typically, after 3–6 weeks into the vegetative cycle, the first few pistils should appear, at random, among nodes on the stem. However, in some strains, their appearance can be delayed, not showing until at least eight weeks. Keep a careful eye on plants during these weeks, and as soon as you spot those first initial pistils, you can breathe a sigh of relief—it’s a girl!

• Harvesting Plants Using The Pistil Method

We already have a comprehensive guide on how to use pistils to determine when to harvest cannabis; but in summary, the white pistils will begin to change colour during the flowering phase. Once the majority of pistils have started to turn orange, brown, and red, then you are ready to cut down those prized buds.

Given that the naked eye can see pistils, they are easier to observe than trichomes when it comes to harvesting. Having said that, using a pocket scope to monitor trichomes will give you a far more accurate timeframe for harvesting.

A SLIGHT COMPLICATION WITH PISTILS

A significant watch-out for growers is that plants can become intersex if subjected to intense stress during either the vegetative or flowering stages. This can happen regardless of the starting sex of a plant; so if you successfully identify female plants, that doesn’t mean you can throw caution to the wind.

An intersex plant will have both male and female reproductive organs. This means pistils will still exist, but the plant possesses the ability to self-pollinate. Be careful during veg and bloom to maintain optimal conditions. Especially during flowering, photoperiod plants are extremely vulnerable to any light leaks in the dark cycle. Whether it’s from grow lights or street lights, light leaks are known to cause plants to turn intersex. Removing or reducing any factors that might cause stress should prevent an intersex plant from developing.

WHEN ARE PISTILS NOT A GOOD SIGN?

So far, the presence of pistils can be used to identify a plant’s sex and to help with harvest timescales; that doesn’t, however, mean the presence of pistils is always a good sign.

Heat and lighting are two primary factors that can cause pistils to continue developing, even if a plant is late into the flowering stage. If pistils continue to build on parts of the bud closest to your light source, then you may have a problem. You should use the original buds, pistils, and trichomes as a sign your plants are ready to harvest, rather than relying on the new growth. They will look immature, regardless of whether your cannabis is at its peak, because of how late into the flowering cycle they began to develop.

To prevent this from happening, a consistent temperature is needed. If cannabis plants are getting warmer temperatures at the top of the canopy than the bottom, the stress can prompt new growth. The same principle applies to light, so ensure coverage is spread evenly to prevent buds from foxtailing. Buds that have developed because of stress can still be harvested and smoked in the same way as the rest of the plant. They are, however, a clear sign that your cannabis is experiencing abnormal conditions, and as a grower, you need to take some form of remedial action.

FINAL THOUGHTS

A final observation when it comes to pistils is that it is not uncommon for new sets of pistils to appear during the flowering stage, even if conditions are optimal. This is a genetic feature that some strains posses. Usually more prevalent in sativas, it can be counteracted by increasing dark time and tricking plants into thinking winter is coming. Reducing light exposure to 11/13 or 10/14 should speed up flowering and support a plant’s readiness to be harvested.

All in all, pistils are a fascinating part of the cannabis anatomy. Their use as a means of sexing plants, and deciphering the correct time to harvest, make them an invaluable tool in the cannabis grower’s arsenal.

Follow the link to identify pistils correctly, and find out why they are hugely important to a grower if you want to harvest mature buds successfully.

Why Some Buds Keep Making New Pistils

If you’re lucky, your cannabis plants buds will all be ready for harvest around the same time as their neighboring buds. However, some cannabis strains naturally finish their buds at the top of the plant first, while other cannabis strains do the opposite. When buds are at different stages of maturity depending on their location on the plant, it can be hard to know when to harvest!

It’s okay to harvest your cannabis plant in parts!

Most growers choose to harvest the entire plant at once, but some cannabis strains make that difficult. For example these buds are at very different stages of development even though they’re on the same plant at the same time!

When parts of the plant mature faster than others, it’s completely okay to harvest in parts starting with the most mature buds. Then you can harvest the rest of the buds as they appear ready.

Many growers accept that some buds are going to be at different stages of development and just try to harvest the plant when most buds look the most ready. That might even be a good thing since you get to try out the slightly different effects from harvesting buds at different stages!

But sometimes you’ll have a case where a marijuana plant keeps making more and more new pistils right when the plant seems just about ready to harvest. Often you can tell something is not quite right…

When is it not normal to keep getting new pistils?

It’s not normal when your plant is making new pistils only on the parts of the buds that are closest to the light. This can stress the buds by heat or because the light levels are too high.

Note: If your plant is also growing weird, round leaves, it’s possible your plant is revegging.

Never-ending pistils is most likely to be heat or light stress if the buds seem to be losing their round, pointy shape from the new growth.

Buds growing in strange shapes can be a sign of heat or light stress. This plant got new buds growing with white pistils right as the rest of the buds started looking done. Each new bud or “foxtail” is covered in lots of new sugar leaves because the plant is actually growing brand new buds like towers or mini colas emerging from the old ones.

Another very common sign of heat or light damage is when buds are becoming fist-shaped because of new growth, especially if it’s happening mostly on the parts of the buds closest to the light

In the following example, the cannabis bud has been damaged by both too much light and too much heat. Although the rest of the buds on the plant appear almost ready to harvest, this bud closest to the light keeps putting out more and more white pistils as new buds grow on top of the old one.

Sometimes you see long and thin foxtails on the sides closest to the light. Luckily, buds formed as part of foxtails or heat stress are just as good to smoke as any other buds, despite their unusual shape 🙂

If you see these symptoms, you should be looking at the older parts of the buds to decide when your plant is ready to harvest. Don’t pay attention to the newest growth because it will look immature even if the plant is ready!

What to Do If It’s Heat or Light Damage

  • Look at older growth to decide when to harvest, not the newest parts
  • Control the heat if you can! Getting the top canopy a few degrees cooler can make a huge difference in your efforts to stop foxtailing!
  • Even if the temperature is okay, move your grow lights further away if possible because sometimes bud damage is caused by light burn. Light stress without heat is most common with HPS and LED grow lights that are kept too close.
  • Any buds formed this way are still perfectly good to use for smoking, vaping, edibles, etc. For cosmetic purposes some people reshape buds during the trimming process, but it’s a matter of personal preference!
  • Consider giving your plant shorter days (longer nights) to “hurry” it to finish flowering. By giving plants a 11/13 or 10/14 light schedule (13-14 hours of complete darkness/day), you will encourage your plant to finish flowering sooner.

When is it Normal for Buds to Put Out New Pistils?

It’s important to remember that it is normal for some strains to put out new waves of pistils two or three times during the flowering stage, even without heat or light damage.

Sativa strains tend to do this the most, though it can happen to many different types of strains. Sometimes the new growth may even look like fox tails, but if it’s happening evenly all over the plant chances are it’s normal and caused by the strain 🙂

Fox tails and new white pistils are normal if they’re staying small and happening evenly all over the buds. This type of fox tail is caused by the strain, not heat or light stress. You see this most commonly on Haze and Sativa strains.

Speaking of Sativas, did you know that some Sativa and Haze strains will usually not make any amber trichomes? If you’re waiting for trichomes to turn amber before you harvest a Sativa strain, you may be waiting a long time. If your plant has been flowering for more than 3 months, sometimes it’s best to wait until the trichomes are mostly cloudy and go from there, without waiting for any amber trichomes.

If your Sativa keeps putting out more and more pistils in a healthy way, and you want to “hurry it along,” you can reduce the number of hours of light they get a day from 12/12 to 11/13 or even 10/14. Giving plants longer nights during the flowering stage causes them to mature faster, and it may be needed to get Sativa strains (some of which come from the equator) to “finish up” in a reasonable amount of time.

More Examples of Heat-Damaged Cannabis Buds

One of the things that many growers immediately notice about heat damaged buds is they keep growing tons of new sugar leaves. Since the plant is no longer in the vegetative stage it won’t make regular fan leaves anymore, but it still will desperately try to grow new leaves to power the growth of these new buds.

Some strains naturally grow more sugar leaves than others but when there’s tons of them and the sugar leaves themselves look odd like this (and the odd growth happens mostly to buds closest to the light) you know for sure it is not normal!

In the picture below, the grow space wasn’t even hot at all. The buds started foxtailing because the LED grow light was too close and the plant started getting light burn. Your plants can be burned by too powerful light even if it’s the right temperature.

This fist shaped bud keeps putting out new pistils on top as a result of heat damage. The rest of the plants already looks completely ready to harvest! In this case, ignore the top pistils and harvest the plant 🙂

Here’s another example of a fist-shaped bud with tons of new white pistils and sugar leaves on top as a result of stress. This case was caused by an LED grow light being kept too close even though the temperature was good.

These buds were also affected by LED grow lights being too close. Notice the odd-shaped buds near the top of the cola. In contrast, the lower buds were shaped normally.

When I first started growing I didn’t realize what was happening when I saw fox tails and strange bud shapes on my cannabis plants. I didn’t realize my plants were trying to tell me something! Now that you know what your plant is saying with its bud shapes, you know what to do!

Some cannabis strains mature faster on top, while others mature faster on bottom. But some plants keep putting out waves of brand new white pistils on top buds, and that can be a problem. ]]>