Meeting – November 2018 tour of Chisholm Institute Hydroponic Facility

About 20 members attended this tour of this educational facility on 8th November. They grow tomatoes and the produce is ultimately sold at the wholesale market but is highly sort after by high-end users due to the excellent quality of the end product. The primary purpose of the facility is education.

We are all quite astonished at the size of the plants. They were about 4 metres tall with about 2 to 3 metres of the plant’s canes coiled about the base of the plant. The plants we saw on the day consisted of a number of varieties. In July 2018 theses varieties of tomato plants were cloned onto a specific different variety of highly productive rootstock. It has only taken 4 to 5 months for the plants to attain the height mentioned above. This has been achieved by controlling the temperature, humidity, light intensity of the enclosure. pH and EC of the nutrients, ventilation. Most of these parameters are computer controlled and all of the information is logged continuously.

Whilst a number of parameters are computer controlled, there is still a significant amount of manual work required. eg loading the nutrients in the mixers, pruning the leaves below the fruit, lowering the plants and coiling the bottom of the canes at the base of the plant, truss pruning and ultimately picking and packing the product. In addition to this since there are insect controls required which involves releasing and propagating predator insects into the enclosure to deal with any whitefly or other in insect pests. the building is not bird-proof so they also have to remove these pests as well without hurting them.

One member asked how we could control whitefly in our domestic hothouses. It was suggested that since our hothouses are generally small and open on occasions it is not practical to use predator insects as they will leave the area quickly if the food source moves or they can escape. Instead, we should use the yellow tape at the top of the hothouse and disturb the plants to encourage the flies to move to the top of the hothouse and stick to the tape. Whitefly is also attracted to the colour yellow.

The productivity of the site is high with an average of 70kg per square metre. This compares to the best achieved in Holland of 90kg per square metre.

Everyone that attended the tour enjoyed themselves and learned a great deal about the potential of hydroponics. We now know why it is difficult to replicate the results we saw today at home.

Some photos of the tour


Staff member pruning tomato plants

Predator insects eggs in leaves of plants. Leaves are left on the floor of near plants to increase wasp population.

Tomatoes in different stages of ripening

Nutrient mixing room



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