Grow three plants outdoors: Part 10: Curing, storage and processing leftovers

We are done! After months of care and weeks of drying, we can finally enjoy the fragrant fruits of our labour. To keep the harvested flowers fresh for a long time, they need to be stored correctly. In the final instalment of our outdoor growing series, we will learn the correct storage procedure, explain why curing is important and discuss what to do with the remains after the harvest.

In the previous instalment we learned how to recognise plant maturity and explained the harvesting process in detail. We also looked at how to dry flowers correctly so that they do not become mouldy and retain the maximum amount of terpenes and active compounds. Correct storage not only preserves their quality, but can even improve it slightly.

Curing

Freshly dried flowers have a healthy colour and an intense aroma. However, their terpene profile may still somewhat resemble straw as a result of the high chlorophyll content. The green pigment also has a bitter aftertaste. A more refined and cleaner flavour is given to flowers by a process called curing, which could be translated into Czech as ripening.

During curing, flowers are sealed in airtight containers, which are opened regularly to allow fresh air to reach the material. Curing usually takes several weeks to months, during which time some of the chlorophyll breaks down in the flowers and their flavour becomes milder.

In addition to chlorophyll degradation, other changes also take place during curing. Terpenes – aromatic compounds in plants – are volatile, and some evaporate and undergo changes even at very low temperatures. This is why the terpene profile of flowers continually changes during drying, curing and storage. Some plants smell and taste best after several weeks of curing, while others may need several months of ripening.

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Step-by-step curing instructions

Prepare the containers: For curing, you will need glass, metal or plastic containers with an airtight closure. Avoid cheap plastics, which may break down under the influence of plant essential oils and release harmful substances. Depending on the amount of dried material you are working with, use containers with a capacity of approximately one litre or more.

Fill the containers: Place the dried and trimmed flowers in the containers so that they are filled to approximately three quarters. Do not pack the flowers tightly together. Moisture would be trapped between them and they could become mouldy.

Storage: Keep the filled containers in a dark and dry place at temperatures up to 20 °C. Add a humidity control sachet of a suitable size to each container, according to the amount of dried material.

Burping: During the first week, open the containers every day and allow the material inside to air for several minutes. Before closing them, gently mix the dried material so that the flowers do not stick together. In the second week, open the containers every other day. In the following weeks and months, air the dried material once a week. Each time you open a container, check whether any mould has appeared on the flowers.

How to store flowers so that they stay fresh for a long time

Terpenes and active compounds in flowers degrade over time. The process is faster if the dried material is exposed to light, air and high temperatures. When stored in a dark place at room temperature, flowers remain relatively fresh for six months to one year.

Dried material lasts longer in a refrigerator or if it is frozen, but care must be taken with humidity. Freezing is suitable only for long-term storage. Repeated freezing leads to greater losses of active compounds and terpenes than normal storage. For storage in a freezer, vacuum bags are best, as they prevent moisture from reaching the flowers. Frozen plants retain their properties for several years.

What to do with the remains of harvested plants?

Flowers are undoubtedly the most valuable part of the harvest, but leaves, stems and even roots can also be used. The remains left after cleaning the flowers have the most uses. The small leaves on and around the flowers are rich in terpenes and active compounds. Trimming remains are suitable for extracts and concentrates, cooking, ointments and tinctures, as well as sifting or water extraction.

Large leaves are not covered with trichomes to the same extent as flowers and contain less resin. However, they are full of antioxidants, minerals and vitamins, and when fresh they are excellent in salads, herbal teas or healthy smoothies, for example. Dried leaves can also be added to ointments and tinctures.

Stems and plant roots are mostly thrown away by growers or added to compost. They contain almost no active compounds. However, roots contain substances that may have anti-inflammatory effects and can be added to ointments and tinctures. Stems can also be used, for example, to make creative decorations.

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That concludes our outdoor growing series. We hope you have enjoyed our shared journey from spring to autumn. Do you not want to miss out on the joy of growing in winter? You can learn how to grow indoors in the series Grow three plants indoors. For further advice and guides for indoor and outdoor growers, as well as regular news from the world of growing, follow the Higarden blog.