Search for new substrate for the cultivation of freesias

Added on 16 March 2023

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Search for new substrate for the cultivation of freesias

Freesias are grown in the soil. The advantage is that this makes it easier to control the temperature of the tuber; cool in the summer and 'warm' in the winter. The soil mass provides a dampening effect when it comes to the temperature. However, there is also a major disadvantage: the soil must be steamed every six months for disinfection. This is an energy and labour-intensive activity. The Greenhouse Horticulture and Flower Bulbs Business Unit of Wageningen University & Research is therefore investigating alternatives for growing in soil and steaming.

Soil has a dampening effect on the temperature because of the large volume concerned, including the sub-soil. However, that large volume also needs to be disinfected after half a year of cultivation. The ideal alternative therefore has a smaller volume but still has a sufficient damping effect. To this end, WUR is investigating four alternatives in a demonstration trial. The freesias (two different varieties) were planted in November 2022.

Four alternatives

One of the alternatives is a floating cultivation system. The advantage of this is that the temperature of the water layer in which the plants float can be quickly adjusted. Moreover, cleaning is straightforward.

In the second alternative, the freesias grow in V-shaped cultivation gutters dug into the soil. The substrate in the gutters uses the damping effect of the surrounding soil. In addition, mechanical cooling is possible through a cooling hose outside the gutter: if that is insufficient, a cooling hose inside the gutter can also be used.