How to deal with harvest residues

The main goal of most growers is to harvest unpollinated flowers full of active compounds and terpenes. But what should be done with the “leftovers” — that is, trim, leaves, stems and roots? For most growers, these are merely waste that ends up in the bin or compost, but that is a great shame. These parts of the plant contain valuable substances that can be turned into home remedies, cosmetics or treats.

Harvest time is always a time of joy for growers, but it also brings more work. Bear in mind that if you decide to make further use of the leaves or roots of the plant, you should treat them with similar care during harvesting and drying as you would the flowers. When drying, ensure the correct conditions, namely low air humidity of around 55%, a temperature in the range of 18-21 °C, darkness and a supply of fresh air. Under no circumstances should you use mouldy dried material or plants treated with pesticides for further processing.

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Sugar leaves

The English term “sugar leaves” refers to the small leaves around the flowers that are covered in trichomes and contain a relatively large amount of cannabinoids and terpenes. You can prepare effective extracts, tinctures or ointments from them, or use them in a similar way to the flowers (sifting resin, vaporising herbal blends).

Do not forget that CBD occurs in dried material in its acidic form (CBDA), which is inactive when ingested. In order for CBDA to be converted into CBD, the dried material must first be decarboxylated, that is, heated to a sufficiently high temperature for a certain period of time. Decarboxylation takes place to some extent during the cooking of oil or ointment itself, but for better effects of the final product it is better to heat-treat the dried material first.

• Enriched butter or oil: Cannabinoids bind very well to fats, so cooking dried material in butter, oil or another fatty carrier (coconut oil, lard) is a very effective extraction method. Simply heat an appropriate amount of dried material slowly at a temperature of about 80 °C for 2-3 hours and then strain it.
• Homemade herbal ointment: There is a great deal of evidence that CBD and other cannabinoids are very effective when applied topically, especially for pain, eczema and skin injuries. You can use medicinal petroleum jelly, coconut or olive oil, shea butter or lanolin as the base for a homemade ointment. The procedure for preparing a basic herbal ointment is simple. Add approximately 20 to 50 grams of dried material to one kilogram of carrier and heat the mixture in a water bath or in an oven set to a low temperature for about 2 hours. The temperature of the mixture should not exceed 80 °C, so that the cannabinoids are not degraded. You can then strain the mixture or leave it to cool and repeat the heating process several times in order to extract the maximum from the dried material.
• Tincture: As with fats, alcohol is also an excellent tool for extracting active substances from herbs. The “green dragon”, or herbal tincture with a high alcohol content, was a common remedy for pain or insomnia in the past. Preparation is easy. Add approximately 10 grams of decarboxylated dried material to 200 ml of strong alcohol and seal it in a bottle or jar. Leave the mixture of herbs and alcohol to macerate for several weeks at room temperature in a dark place. Finally, filter the mixture through a coffee filter.
• Sifting resin: Like flowers, the leaves around them contain a significant amount of trichomes with a stalk and head, in which active substances and terpenes are hidden. The trichomes can be separated from the rest of the dried material mechanically or with a suitable solvent. The result is a concentrated “resin” (hashish, ice hash, rosin, resin) with a high proportion of active substances and terpenes. Sifting resin through a fine sieve (so-called dry sift) is one of the oldest methods of producing herbal concentrates.
• Vaporisation: Inhalation of vapours rich in active substances and terpenes is a very effective and fast way of consuming medicinal herbs. For this purpose, thoroughly cleaned, dried and mature flowers without seeds are most suitable, but the leaves around the flowers also conceal medicinal potential. However, the consumer must be prepared for the fact that they do not have such a delicate flavour. A great way to give less aromatic dried material a pleasant scent is terpene sachets.

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Large leaves

Compared with those on the flowers, the trichomes on large leaves contain a very small amount of cannabinoids and valuable monoterpenes. Nevertheless, they are rich in antioxidants, chlorophyll, fibre, minerals and vitamins, which makes them an excellent ingredient for the kitchen. You can also process them into ointments, but bear in mind that a larger amount of dried material will be needed than if you used flowers or sugar leaves.

• Green smoothie: Add fresh leaves to your favourite smoothie.
• Herbal tea: Pour hot water over the dried leaves and leave to infuse. The infusion will have an earthy flavour and calming effects. You can also add other herbs to the herbal tea, such as mint, lemon balm or even ginger and honey.
• Salads: You can use the leaves in salads. They have a distinctive flavour that pairs wonderfully with mustard dressing, strong cheeses and fruit.

Roots

Roots are probably the most overlooked part of the plant among growers, yet they have a long tradition in folk medicine dating back thousands of years. Ancient Chinese, Greek and Roman texts already describe decoctions, compresses and pastes made from roots used against pain, inflammation, cramps or bleeding. Even in the 18th and 19th centuries, they were recommended for rheumatism, inflammation or urinary problems. Although roots contain only trace amounts of cannabinoids, especially CBD, they also contain friedelin and epifriedelanol, which are known to have antioxidant, anti-inflammatory or anti-cancer effects.

• Tincture: Roots are a great ingredient for the “green dragon” whose preparation we described above.
• Balm or ointment: You can also add roots to a herbal ointment. First dry them and then crush them into pieces or a fine powder. Then add the roots to the herbal ointment and proceed according to the instructions above.

Stems

Of all the residual parts of the plant, stems contain the fewest active substances, but they are rich in cellulose and lignin, that is, strong plant fibres. The best use is composting or mulching, or you can make decorations from them. We do not recommend using dried stems as supports for plants, because they may become mouldy and spread mould spores into the surroundings.

For more tips and guides for beginner growers as well as experienced growers, visit the Higarden blog.