This study has been set up to explore the biological cultivation of turmeric (Curcuma longa). With this trial we want to determine whether the local cultivation of turmeric is possible in a Flemish greenhouse and whether this would be economically viable. This is a follow-up trial of a trial in 2020 (see REP_GB20 HETT01) where a first successful biological cultivation of turmeric was performed in a Flemish greenhouse. The aim for 2021 was to validate these results and to create a more uniform yield.

The trial was set up at PCG (greenhouse) in Kruisem, Belgium, in a design with 2 parallels and a plot area of 1.8 m². The turmeric was pregerminated and then planted on 21/04/2021. It is possible to grow marketable turmeric organically in a Flemish greenhouse.

The aim for 2021 was to validate these results and to create a more uniform yield. These key questions are examined:

• Is it possible to grow marketable turmeric organically in a Flemish greenhouse?
• What are the preconditions for local organic turmeric cultivation?
• Is pregermination a good strategy to increase uniformity and yield?

Objects

Discussion

The results of the pregermination assessment show that although there was no above-ground germination, the pregermination was successful. All rhizome pieces showed underground germination and not one piece had rotten away. After plant, the uniformity of the crop was also very high during the trial. Definitely at the beginning of the cultivation, contrary to the cultivation in 2020 (see REP_GB20 HETT01). As a result of this pregermination, also no loss of plants was observed during the trial. In 2020, more than 50 % of the plants was lost.

On 3/11/2021, an average of 1211.38 grams rhizomes was harvested per plant, resulting in a net yield of 121.14 tonnes rhizomes per hectare. The harvest around two weeks later (15/11/2021) yielded 138.67 tonnes rhizomes per hectare. There was no significant statistical difference in these yields, although the absolute numbers suggested that a longer cultivation period may have resulted in an even higher yield. An average of 129.91 tonnes rhizomes per hectare was harvested during these two harvest moments. The variation in the different harvested weights per plant was also much less than in the 2020 trial, from 462 grams per plant to a real outlier of 2918 grams per plant.

During the trial, samples were sent to project partner Avans to determine the curcumine content of the turmeric rhizomes. From September to November on, this curcumine content fluctuated around 7 mg per g turmeric dry weight basis. There was no ‘curcumin growth’ observed during the trial. Only in December, this lowered drastically, probably due to the fact that these plants weren’t irrigated for almost 1.5 months and therefore were ageing.

Conclusion

It is possible to grow marketable turmeric organically in a Flemish greenhouse. Definitely when combined with pregermination of the rhizome pieces. With this strategy, a uniform yield of 129.91 tonnes per hectare can be harvested. Compared to literature (35 tonnes per ha, Jalgaonkar et al., 1988) and the trial in 2020 (49.27 tonnes per ha), this is an impressive result. Aim of the project is to harvest curcumin and not only net weight of rhizomes. Next trials should aim for high curcumin harvests.

Read the full report Further exploration of turmeric (curcuma longa / CURLO) greenhouse cultivation

Cooperation

This trial was carried out with support from the Interreg NWE project CURCOL "Curcumin based sustainable Colours".