Harvesting, Drying and Curing Marijuana
OK. You’ve grown your big buds from a tiny seedling to a mature cannabis plant. The hard work of growing is done, and your plants are top heavy with crystal covered buds. The choices you make at this stage will determine the quality and potency of your final product.
There are three key steps to producing amazing resinous buds at this stage:
1. Timing your Harvest
2. Proper Drying of Buds
3. Proper Curing of Buds
We’ll walk you through each step and show you how to maximize THC, CBD and terpene content. Follow this guide and you’ll enjoy the dankest, most flavorful buds you’ve ever smoked, and you’ll get higher than you ever thought possible from home-grown weed.
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Timing Your Harvest
Why it Matters:
Knowing when to harvest your buds is essential to maximizing the cannabinoid content. If you harvest too early you’ll miss out on THC, CBD and other good stuff, but if you wait too long these same molecules will start to degrade.
Maximizing THC in the Bud
Let’s take THC as an example. While it is present throughout the plant, this delightfully psychoactive molecule is most highly concentrated in the resin on the buds. The THC crystals, or trichomes, begin developing partway through flowering, but they really start to coat the buds in the last week or two. Waiting until the trichomes are fully developed will maximize the THC content and thus the potency of the bud.
If you wait too long to harvest the resin glands will start to degrade. THC and THCV in the buds will also break down into CBN. This cannabinoid produces heavy sedative effects and a somewhat unpleasant drugged sensation. Proper harvest and drying will limit the amount of CBN in your final buds.
We know now that THC isn’t the only important molecule in marijuana. CBD, CBG, CBN and other cannabinoids moderate the effects of THC. Some, like THCV, have psychoactive effects of their own.
CBD is the most popular cannabinoid after THC thanks to its medicinal effects. It is not psychoactive, but it does interact with THC and can affect the quality of the high. Plus it has pain killing, anti-nausea and other important medicinal effects.
CBD does not degrade over time like THC. However, CBN has been shown to increase the calming and analgesic effects of CBD. This means that if you wait to harvest until some of the THC in your buds has degraded into CBN you can get a greater benefit from CBD.
You can see why timing your harvest just right is important. You didn’t work hard all these months growing big, beautiful, resinous buds just to lose half your THC to CBN or miss out on potency by getting excited and harvesting early.
How to Tell When it’s Time to Harvest
Most seedbanks give you a rough estimate of how long each strain needs to flower before harvest. This is never exact though; there are too many variations in different growing conditions to be able to put an exact length of time on it. Add to that the variation in phenotypes inherent in most cannabis strains, and the varying preferences of individual marijuana users, and you have quite a wide window of opportunity.
There are lots of signs that your plant is approaching maturity and you are ready to harvest, dry and cure your marijuana. As the flowers grow they will merge together into heavy kolas. You will notice each ovary swell and tiny crystals will be visible around the flowers. The flowers will become sticky to the touch and the aroma may become pungent. As the flowers swell the white pistils begin to darken, going from white to a reddish brown.
During this time some of the larger fan leaves may begin to yellow and wilt. This is a perfectly natural part of the grow stage. It is OK to remove these leaves and allow more light to the lower parts of the plant.
Most growers use the color of the trichomes to help them decide exactly when to harvest. The trichomes are the tiny structures on the flower (and trim leaves) of your plant that produce the resin where all that THC goodness is. Do not confuse them with the pistils which are the long hairs protruding from the flower.
To get a proper look at the trichomes you will need some sort of magnifier. Simple 20X jeweller’s magnifying glasses, bought on ebay or loupes are easily and cheaply available. Not only do they allow you to inspect the trichomes properly, they also open up an amazing world of imagery and an aspect of your plant that can be fascinating to look at.
So what exactly is it that you are looking for?
As your plant matures the trichomes will go though three observable changes;
- Trichomes swell and heads flatten or ‘mushroom’
- Trichomes change from clear to milky or clouded
- Trichomes begin to turn amber or brown
The image below shows fully formed trichomes going from clear, to milky, to amber.
There are actually three (possibly more) different types of trichomes on cannabis buds, secreting many different cannabinoids and other substances. More trichomes don’t necessarily mean more THC… each strain and each bud will produce its own unique mixture of cannabinoids, all of which interact with one another and your body to create the many different “high” experiences.
However the changes in trichome color can provide a decent guide to the relative levels of THC and CBD in each bud.
CBD develops later on than THC in flowering. In fact, THC and the flavor imparting molecules called terpenes peak at roughly the same time, when the trichomes are turning milky or cloudy.
CBD production doesn’t peak until later, when the terpenes are reddish or amber in color. At this point much of the THC has already degraded into CBN, adding to the sedative effects of CBD.
If you observe the trichomes carefully you can choose the moment of harvest to meet your own particular preferences.
Do you prefer a heavy physical stone, or a lighter head stone?
As a general rule, the longer you leave you plant, the heavier the stone.
For most growers harvesting when the trichomes are all clear is too early. Marijuana with clear trichomes will still get you high, but the effects may be light.
Some growers like to take their plants when the trichomes are all milky. This will give you a good hit, but without being too heavy.
Most growers like to harvest when a given percentage of trichomes have turned amber; anywhere from just a couple of individual amber trichomes to around 80% amber. The stone that you can expect just gets heavier and more physical the further you go along this scale.
Of course, as always, the strain that you choose can have some influence on this. As a general rule you could say that:
- Indica dominant strains have a heavier stone by their nature. For indicas there may be no need to wait for amber as partially cloudy trichomes may still give you a body stone.
- Sativa dominant strains are by their nature more cerebral and less physical. To get a good bake from a long flowering sativa you may need to wait until at least 25% or more of the trichomes have turned amber.
You will need to learn from your own experience of the results you get from your set up. The rule of thumb remains true though – the longer you leave it, the more narcotic the effects.
How to Harvest Marijuana
Now you know why timing your harvest is important and how to go about doing it.
Before you actually cut your plants down, we need to take a step back and consider flushing your marijuana plants.
Whether they are grown in soil or a hydroponic medium, cannabis plants can suffer from a build-up of salts or nutrient residues. Many growers flush their plants using plain water every 10 days throughout the grow to help clear out this build-up.
When you feed your plants they do not use all of the nutrients that you give them immediately. Some are stored and used later on. But if you continue feeding and your plant never has to use up those reserves, they accumulate and stay in the leaves, stems and buds. If the nutrient mix you are using is not perfectly balanced for your plants’ needs, they can suffer a condition called “nutrient lockout”. The different molecules in nutrients work together. If there is too much of one and not enough of another the plant may become unable to use any of the nutrients or minerals.
When nutrient lockout occurs the plants may show deficiency symptoms that do not go away with extra nutrients.
To prevent or fix nutrient lockout you need to run clean water through the system to clear out all the built up nutrients and then start feeding again.
So you may need to flush your plants when:
- You switch nutrients (for example at the start of flowering)
- When your plants show symptoms of nutrient lockout
- Every 10-14 days to prevent nutrient lockout
Flushing throughout the grow prevents nutrient assimilation problems. Flushing before harvest improves the quality of your buds. There is a lot of debate on the usefulness of flushing before harvest. Some growers believe it is useless and has no beneficial effects. Others say that flushing reduces the THC content of the buds by depriving the plants of needed nutrients. Others claim THC content is boosted because the plant is starving and ramps up its growth to try to finish flowering before the perceived threat of “winter”.
Yet most growers do flush their plants for 3-7 days before harvesting. The idea is that nutrient residues in the buds can create a chemical or acrid flavor and a harsh, burning smoke.
If you do choose to flush your plants before harvest, follow these basic methods:
Flushing Marijuana in Soil
To flush marijuana grown in soil you need to run lots of clean water through the system. Many growers use rain water. You can add a flushing agent like Clearex if you prefer, although it is not necessary. pH your water to around 6.2 and run it through the container until you have around 80% – 90% run off. The actual amount will depend on how dry your soil is and how well it is drained, but you should be looking to put through about the same volume of water as the volume of your container.
Flushing Marijuana in Hydro Systems
To flush marijuana in hydro systems you should just run clean water through the system for the last few days. pH your water to about 5.8, although pH is not as critical at this stage as there are no nutrients to lock out.
After flushing, in both soil and hydro, you may experience leaf yellowing as the plant becomes deficient in nitrogen. This is normal and nothing to worry about.
Another thing you might want to consider just before harvesting is leaving your mature plants in total darkness for 36 hours. Although we can find no hard evidence to back this up, many growers swear that it gives their plants some extra potency by shocking the plant and forcing the very last of the its energy into creating resin.
Chopping Down Your Weed
Before you cut any kolas or branches, remove the larger fan leaves. This is often easiest when the plant is still standing. Some growers remove many of the smaller leaves at this stage too, but if you are not in a hurry it is beneficial to leave them on throughout cutting and drying. These little leaves will protect the trichomes and cause the buds to dry slowly, preserving more flavor, weight and potency.
It can be tempting to chop and hang each entire plant, but the buds will dry better if you do it in sections. Treat each branch and kola separately so they won’t touch each other when hanging to dry.
Using a sharp pair of secateurs or Fiskars cut each branch from the plant. Remove the large fan leaves if you have not already done so. Handle the branches very carefully; rough handling can cause the trichomes to drop off and that is something that we definitely do NOT want.
Now it is time to dry those lovely sticky buds.
How to Dry Marijuana
Getting the Best Flavor:
With over 100 different flavorful terpenes and flavonoids, cannabis is one of the most diverse plants in terms of taste and smell. Whether you enjoy the sweetness of Bubblegum or the acidic bite of Sour Diesel, the complex flavors of different strains are dependent on these delicate molecules. Improper drying and curing damages the terpenes, resulting in bland weed that smells like hay.
There are three basic tricks to preserving the terpenes in your buds:
- Dry Slowly – Fast drying gets you smokeable bud quickly, but it results in light weight, bland buds. Dry slowly to preserve flavor, weight and smell.
- Provide Good Air Circulation – this prevents the growth of mold and fungus, which can not only damage the flavor but ruin the entire bud
- Cure for 2-4 weeks – Careful curing brings out the terpenes and makes for extra tasty buds.
Hang each of your freshly harvested branches upside down in your drying area. Your drying area should be dark and have a good supply of clean fresh air. Good ventilation is key here. A fan will help, but try not to train it directly on your plants. What you want is air circulating, not blasting at them. Remember to provide lots of space around each individual branch.
Heat will cause your plants to dry faster, but as we explained above, this is not always better. An ambient room temperature should be sufficient. Inspect your plants regularly to see how they are doing and turn them around so that the airflow in the room gets a chance to get to all parts of the buds.
A lot of growers use custom made drying cabinets or boxes. This is basically an enclosed, controlled environment to dry your weed in. Some simple DIY could build you a box with hangers and a throughput of fresh air. You can also buy commercial weed drying cabinets such as this Supherb Drying Cabinet that is suitable for 24 plants.
Drying can take anything from a few days to a couple of weeks. The average time is somewhere around a week. You will know that your plants are dry when branches and stems crack rather than bend between your fingers.
This dried weed is smokeable now, but to get the best of the flavors and potency a final cure is necessary.
How to Cure Marijuana
Now is the time to trim your marijuana before the final cure. To give your buds their final manicure use a clean sharp pair of scissors to gently remove any remaining leaves that are shielding the buds. Part of this process is aesthetic and it is down to the individual to decide how neatly they want their buds trimmed. Wherever you are on the tidy bud spectrum, do not throw away the trimmings, the small trim leaves are often loaded with trichomes and if you don’t want to smoke them they make great edibles.
Separate the individual buds from the stems and store them in clean glass jars. Plastic tubs or bags will do, but we prefer glass.
For the first week or two that the buds are in the jars, open them up twice a day and allow them to ‘breathe’ for 15 minutes. This allows for a complete air exchange and removes any remaining moisture.
Your buds are now ready. Different strains may cure at different rates and you will often find that, if correctly stored, your weed gets better over time.
Good curing can make all the difference to your final smoke and is the finishing touch to all your hard work in the grow room.