white hairs on weed

When to harvest cannabis plants?

There are many reasons why growing weed for personal use may seem like a good plan but is harder than you think. The apparently simplest things are often the most difficult when growing weed. Most mistakes are made with things like watering or feeding. Besides, too many weed plants are still harvested way too early by impatient growers. Anyway, how exactly to determine when to harvest cannabis plants and why is it so important to choose the right moment?

Harvesting cannabis plants at the right time not only affects the overall quality but also the yields. Harvest too soon and your weed will be too weak; harvest too late and it will send you to sleep. But how exactly can you tell when the right time arrives? This article will explain everything you need to know about when to harvest your cannabis crop.

When is my weed ready for harvest?

There are basically two methods you can use to determine whether your cannabis plants are ripe for harvest or not. The first method is a visual method and involves simple observations of the hairs on the pistils, the technical name for the female reproductive part of the cannabis flower. The second method – the trichome method – is a bit more technical. Let us tell you how to know when to harvest your weed plants, explore what both methods involve after which then you can decide which one is right for you or use a mixture of both.

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1. The Pistil Method

If you prefer to operate in a more down-to-earth way and feel in tune with your growing plants, the observing pistils (hairs) method could work for you. Besides you don’t need to buy any equipment as long as your eyesight is working well so this method is ideal for those on a budget.

You need to know the signs that indicate your plants are ripe enough to be harvested. Look out for long white threads (the flowering hairs) that come out of the flowers.

The flowers of a female weed plant have long, white, thick hair during the flowering period. These hairs are most often a whitish color during flowering. When about 80% of these white hairs have turned brown, it is time to harvest, although there are exceptions to the rule, depending on what you want from your cannabis plant and on the strain.

Wait until no new white hairs appear in your buds. You will notice that the buds will have started to smell very strongly by this point in the cycle, the entire nursery or grow room will probably smell strongly of weed. The buds also look thick, bulgy and properly padded – mature and ripe, in other words.

40% of the white hairs are brown and dried up

Wait until at least 40% of the white hairs on the tips are brown and dried up. When this is the case, you are at the start of the harvestable period. If you harvest your weed at this moment it will give you a more energetic effect when it is smoked and the weed is not yet at its peak in terms of potential.

40% – 50% of the white hairs are brown and dried up

When 50% to 70% of the hairs are brown and dried up, your weed is at its peak in terms of potential. Your weed now contains the most THC. So if you are looking for potency, now is the time to harvest your weed.

80% – 90% of the white hairs are brown and dried up

When 80 to 90% of the hairs on the tips are brown and dried up, your weed has passed the peak of THC. The weed that you now harvest will give a more relaxing effect that makes it harder to get up from your couch. This is because part of the THC in the weed has been converted into the more relaxing CBN. People who are looking for weed with good painkilling properties would be well advised to harvest their weed at this point.


However, the harvesting time also depends on the species. Some types of weed need to flower longer than others. With some, the flowering process starts later and with some earlier. Yet, the above information provides a pretty solid answer to the question: when to harvest cannabis.

The aforementioned advice is a good guideline but you should be aware that with some strains, it can be much more tricky to work out if the plant is ripe to be harvested. Different strains of marijuana can present in different ways when they are ready for harvest. Some varieties, for example, manage to retain most of their hairs white even when they’re more than ready to be picked.

If you suspect this might be the case for your cannabis plants, the best thing to do is to find out as much as you can from someone who has successfully grown your variety before. This might be the breeder or a grower. It’s also sensible to look for online images of the appearance of your strain when it is ready to be harvested.

Other signs that indicate it’s time to harvest:
  • The plant looks less healthy, leaves start to droop, and the number of yellow leaves increases at the bottom.
  • The weed plants will stop being so thirsty and use much less water than before.

Warning: Do not grab the buds or manhandle them too much during the flowering period, this will damage the flowering hairs and cause them to die and dry out. Buds that are grabbed very often sometimes even look ready for harvest because all the delicate flowering hairs are damaged by grasping and turn brown as a consequence. You need to be gentle!

2. The Trichrome Method

This method is a bit more technical and does require a bit of scientific knowledge, but if you want to grow cannabis for its THC levels, this method will give you a much higher level of accuracy. Never fear, this article will give you all the info you need to become a cannabis trichome expert and harvest your crop when it is at its pinnacle in terms of THC and other goodies.

What exactly are trichomes?

Trichomes are very important as they are responsible for the THC of the weed plant, the very substance that makes you high. If you look closely at a weed plant in bloom, you will notice very small stems with bulbs on them. These are trichomes but they are pretty hard to see with the naked eye.

With this in mind, you may benefit from using the following magnifying tools to make inspecting of the trichomes easier and more accurate. Using one is not completely necessary but will help you get the timing of your harvest perfectly right.

Jeweller’s Loupe – A jeweller’s loupe is a compact round magnifying glass that is inexpensive and yet more than capable of getting the job done. A cheap one should give you a 40x magnification. You simply hold it over the blooming cannabis plant and peer through the glass.

Digital Microscope – This has to be one of the best gadgets to calculate the right harvesting period. Digital microscopes are available to suit all budgets, but a good-quality digital microscope can now be purchased for under £50 and will allow you to view images of the trichomes on your laptop or any connected device. They are ideal if you want to share images of your trichomes and canvas second opinions.

Now comes the technical part; what to look for when looking through your microscope or jewellers loupe:

The trichomes you are attempting to observe look a bit like tiny mushrooms. You may also notice minute, transparent hair-like trichomes minus the mushroom head. These are unimportant as they won’t have any impact upon the final strength – you need to pay close attention to the trichomes with the little ball on top. It’s this tiny head that holds the power as this is the location where most of the THC and other key chemical properties of cannabis, such as CBD and CBN are concentrated. As these trichomes are the most responsible factor regarding bud potency, knowing how to tell when they’ve achieved their highest THC levels will help you determine exactly the right time to begin your marijuana harvest.

Look for the following signs which indicate when it is time to harvest:

  • Clear trichomes If all the trichomes on the plant are still clear or transparent, it is too early to harvest. The plant is not yet fully ripe and should be left to flower for a while longer. However, for inexperienced growers, it can be difficult to judge whether a trichome is clear and glass-like or cloudily opaque. This is where the advantage of a digital microscope that can capture images and allow you to compare online later really becomes crystal clear.
  • Clear and milky trichomes If most trichomes begin to turn whitish, you could potentially harvest now – the results will give an energetic vibe and a nice euphoric feeling after smoking.
  • Yellow trichomes If you are going to harvest now, you will get a narcotic high which is good for insomniacs.
  • Mostly yellow with some whitish trichomes If you were to harvest your plants now, the resulting weed would generate a nice buzzy stoned feeling in your head and body.
  • Only brown trichomes Oh dear, you’ve left it too late, the plant has passed its best time. If you harvest now you will have little or no effect from the THC. Better luck next time!

Summary: General tips and tricks

Growing and harvesting marijuana takes a moderate amount of gardening skill and there are always new hints that can provide additional insight. Here is some additional advice about harvesting cannabis based on the colour of the hairs and the state of the trichomes. Follow our rules and you’ll stand a good chance of harvesting perfect weed every time!

  1. You can tell that your plant is too immature for harvest if it still has white “hairs”, the majority of which still stick straight out; especially if its trichomes are all still clear. Harvesting now will result in low yield and non-potent harvests. Wait until your plant has ceased growing new white pistils and lots of the white hairs have turned into an amber brown and curled inwards.
  2. THC is at its strongest when most of the trichomes look milky white when observed under a microscope. Approximately 50-70 % of pistils have been browned and harvesting now will lead to a more trippy weed. However, some strains, such as Sativa and Haze have trichomes that never really turn amber. If they’ve turned white for a while and haven’t changed for a few weeks, you may need to get harvesting.
  3. If you want weed that will get you properly stoned, you need to aim to harvest at the end of the season, when most of the trichomes have turned into a dark amber or gold shade. Experts say that amber trichomes derived from Indica varieties produce the best body highs. A good proportion of the THC will have converted into CBN which is far less psychoactive and is known for its calming and anti-anxiety effects.
  4. Colour disparities – Don’t be alarmed if you notice red or even purple trichomes – this is normal for some strains. As a rule of thumb, harvest when the majority of pistils are nice and dark.
  5. Don’t leave things too late If you spot trichomes looking grey or shriveled, you have missed the harvest window. Harvesting now and the end product will make you drowsy without any other pleasant effects. This is not a common problem though, as most growers are far too eager to get harvesting and you the harvest period open for about four to five weeks.
  6. Cure your buds properly. Curing them for about a month will increase their anti-anxiety and calming properties.
  7. Do things in stages If you are feeling excited about harvesting your marijuana plant, pull buds off the plant that look the most mature, dry them and check the potency for yourself. You can do this over a few weeks. Harvesting the buds in stages (starting off slowly with small batches) is a good way of abating the excitement. It will also help you work out where your preferences lie. There is nothing wrong with cutting off a few pieces in a go.
  8. Follow your gut instinct Cannabis harvesting can seem daunting but always listen to your instincts. We think that using a combination of both methods is the best way of helping you choose the optimal time to harvest, but knowing how you want the end product is a very personal thing. This means that even the best methods are just general guidelines. But hopefully, you’re now closer to getting your weed the way you want it.
Final hints before your harvest

1. Be prepared Before starting your harvest, it is handy to arrange everything in advance, ensure a clean environment, good clean scissors, possibly plastic gloves, and make sure your drying loft is ready to be used. You don’t have to go to the extremes of Walter White in ‘Breaking Bad’, but it’s good to get organised. Start by cutting away all the large leaves, leaving a plant with many small leaves and no large leaves. Cut away half a centimetre of leaves around your buds, the protruding weed leaves will dry and shrink. You could possibly leave THC on it.

2. How to physically harvest the cannabis plant – There are several methods, it really is a matter of trial and error and personal preference.

Leave the plant in the pot or soil and cut off the large leaves. Then cut away the small leaves around the tops so that you end up with a bare plant with only the flowers. You cut a branch every time and cut the leaves off again. So you can cut the twigs per piece, this is a bit more convenient because you don’t have to turn your plant every time.

You can also cut your weed plant in its entirety and lay it down to cut off branches.

Related article: how to harvest weed?

What can you do with leaves or cutting waste?

After harvesting, you have a whole mountain with leaves and clippings. However, many of these residues can still be used for processing in recipes or tea. You can also compost any unwanted vegetation.

You can do a lot of fun and useful things with the waste, but it is important that you know which leaves you should throw away and which leaves can be used.

Cannabis, weed, pot, herb – the list of names for the wonderful plant is endless, but, as you can see, the knowledge of when to harvest, while not completely straightforward, is, nevertheless, less complex than it might first appear.

Our advice is: follow our tips, read as much around the subject as you can – our blog posts are a good starting point – and talk to as many experts as possible. You’ll be an experienced cannabis cultivator before you know it!

Wondering when to harvest weed plants? Cannabis harvest time is determined by 2 methods. Check this blog and learn when your weed is ready to havest!