Drying and Curing – The Path to a Flavorful Harvest

When a grower finally harvests ripe flowers, there comes a moment of satisfaction – and at the same time one of the most important phases of the whole season. The way you dry and let the harvest mature determines the taste, aroma and effect of the resulting dried product. A few mistakes are enough to waste months of work. So how should you dry and cure to make the result worth it?

What do you imagine when you hear “quality dried product”? Is it a strong effect, a pronounced aroma or a delicate taste? Probably all of those together. These properties are due to cannabinoids, terpenes and other compounds that form and are stored in trichomes. To preserve as much of them as possible in the herbal material, you must handle the harvest carefully. Proper drying and subsequent maturation (curing) decide whether your harvest will smell fruity or like wet hay.

Different drying methods

The first step to a flawless yield is gentle and slow drying. The goal is not merely to dry the plant material, but to do it so that as many active compounds as possible remain in the dried product. These are hidden in trichomes, microscopic glands on the surface of flowers, leaves and stems where cannabinoids and terpenes are produced. Rough handling can knock off trichome heads, which fall from the flowers as a fine powder resembling resin. The most valuable trichomes are those on the flowers — they contain the highest amount of active compounds and have a higher content of monoterpenes than trichomes on leaves and stems.

The more you handle the plants, the more trichomes you will lose during drying. The gentlest approach is to remove only the dry and yellow leaves from the plants and dry them whole, hung upside down. This method ensures slow curing, which is important because herbs dried too quickly lose terpenes and develop a bitter taste. Optimal drying time is about 7 to 21 days at 16–20 °C and a relative humidity of around 55%. In that time the plant material should lose roughly 70–80% of its weight.

There is always some risk of mold during drying. This is especially a risk with large outdoor plants or those already affected by mold. In such cases, remove all large leaves from the plants before drying. This increases air circulation around the flowers. Flowers will dry better if you separate plants into individual branches. Alternatively, you can dry flowers broken into smaller parts on drying racks. Before doing that, don’t forget to remove the small petals (wet trim).

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How to equip the drying room

The room for drying herbs must be well ventilated and completely dark. Light degrades cannabinoids and terpenes, and air circulation is important so the plant material does not sweat and start to mold. If you don’t have a suitable place in the house, growbox (grow tent) with an operating exhaust fan can serve for drying herbs.

Throughout the drying process monitor temperature and humidity in the drying room with thermo-hygrometer. If humidity rises too high, the best solution is a dehumidifier, where you only need to set the desired humidity. When drying in a growbox, place the dehumidifier in the room with the grow tent, not directly inside it, so that warm air does not dry the herbs too quickly.

Well-dried flowers can be recognized by being dry to the touch, slightly springy and easy to break off the stem. If the herbs crumble easily between your fingers, that’s a sign of overdrying. That’s not ideal, but not all is lost. If you place the dried product for a day or two in a space with higher ambient humidity (above 65 %), it will regain some moisture. Check the flowers roughly every 6 hours.

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Trim and curing

If you didn’t do it at harvest, after drying you’ll need to clean the plants of remaining leaves, especially the small leaves around the flowers (dry trim). Trimming is fiddly work and we recommend equipping yourself with sharp spring scissors with a fine tip. Disposable gloves will also be useful, because the resin of some medicinal plants can irritate the skin. Don’t forget to add disinfectant alcohol to the cart for cleaning tools and hands.

Dried and trimmed buds can theoretically be used immediately, but you can further improve the quality of the dried product. Curing (maturation) is a technique in which the dried product is left to mature for several weeks to months under controlled conditions. During this time residual moisture in the dried product redistributes evenly and the plant material loses some chlorophyll, which has a bitter taste.

Curing is usually done in glass or metal jars that can be sealed airtight. Fill the containers with trimmed flowers to about three quarters so some air space remains. You can add a humidity control packet inside to ensure maturation proceeds under optimal conditions. Finally, store the maturing dried product in a dark place with a stable temperature between 15–18 °C.

Depending on the cultivar and personal preference, you can let the dried product mature for several weeks to months. In the first week open the containers daily and let the product air for about 20–30 minutes once a day, but watch the ambient humidity. If it’s raining outside, indoor humidity can also be around 70–85% and the dried product will absorb it very quickly. In such cases it’s a good idea, before opening the jar, to isolate the room from outside conditions and measure the humidity in the room where the jar will be opened. Before sealing, gently stir the flowers inside the container with a clean tool so fresh air reaches all parts. In the second week opening the containers twice to three times a day is sufficient. In the following weeks and months ventilate the dried product at least once a week.

For more tips and guides on legal cultivation visit our Higarden blog for both beginner and advanced growers.