Greenhouse weekend duty - September 13-15, 2019

For our greenhouse duties on the weekend of Sept 13 to Sept 15, we had 3 main tasks to do. On Friday, we decided to collect cuttings from the stock plants around the greenhouse area. We propagated approximately 6 full trays of cuttings from plants including Geraniums and many different types of Coleus. Cuttings were planted in a mix of Pro Mix HP and perlite. This mixture has more pores for water and air to get trapped in, providing a nice moist atmosphere for new root growth.

On Saturday we collected the sticky traps above the odd numbered benches in the greenhouse to monitor for pests that could be damaging our crop of poinsettias. We do this as part of an IPM (integrated pest management) strategy which aims to reduce the number of pests affecting the crop. Poinsettias are known for being attacked by White Fly which damage the plant by sucking out sap in order to continue to grow from the larva stage to the adult stage. In order to deal with White Fly we use parasitic wasps that hunt and attack the larva, laying eggs in their stomachs to kill the larva upon birth. Another pest we had noticed was a Sciarid Fly which can be damaging as its larva will feed on roots. They cannot find anything else such as decaying matter. We believe this issue may be related to inconsistent watering cycles.

We also measured the pH (parts of Hydrogen) and EC (electrical conductivity). Measuring the pH allows us to see how available each element is to the plant, as different pH values can essentially “lock out” nutrients in certain ranges. This measurement was completed using the pour through test. In this test, we will pour completely neutral distilled water through each plant to be tested. Once that is done, we collect the water that drains out the plant and we test it using a pH meter. Our crop tested at an average of 6.7, which is outside of our ideal range for this crop. At the same time, we also measure each plant for soluble salts. These salts accumulate in the soilless media as we fertilize the crop. Nutrients are bound to salt molecules, so as we increase the fertilizer amounts, the more salts that will build up in the media. Excess salt is flushed every 5^th watering. The crop had been flushed at some point before our duties for the weekend commenced, so our EC readings were well below our goal, most of them being around 0.5 or lower.