Week 39

Environmental Conditions:

Day: Heating Setpoint  20C  Cooling Setpoint 25C

Night: Heating Setpoint 20C  Cooling Setpoint 25C

*heating set point for day and night period increased to 20C – see observations below.

Supplemental Lighting:

Supplemental light to come on when light levels drop below 600 w/m2 for more than 30 minutes. Lights to turn off when light levels are above 650 W/m2 for more than 30 minutes.  Supplemental lighting between the hours of 6:00am – 7:30pm. 12.5-hour day.

Hours of Black Out: None

EC target is 1.5 (1.8 is better) – 2.0  pH target is 5.7 – 6.3

EC  and pH – see picture


Each watering event includes fertilizer so far since we are within our EC target range. Students will work in the greenhouses to determine EC/pH of the crop next week.  After pinching, we applied the Ca(N03) fertilizer once and then an application of Mg fertilizer afterwards.  We determined that since the roots were developing at an acceptable rate and in appropriate numbers it was okay to add the Mg fertilizer to support the vegetative growth. 

Moving forward, each watering that requires fertilizer we will alternative between the CaN03 and Mg fertilizers.


  • General environmental observations from all groups:
    • Floors were wet, fans on, lights on, shade curtain open (you can see the sky – no need to protect the plants with the shade curtain anymore since they are responding/recovering well post-pinch),signs of root rot à suspected over watering (watering too often).
  • This week we recorded the information from the yellow sticky cards that students set up as part of their yellow sticky card lab #1.  All groups determined that we have a major fungus gnat problem and worked together to determine cultural, physical, mechanical and biological control treatments that they could apply to manage the pest pressures.
  • Whitefly populations are concerning as well.  Students found whiteflies on their yellow sticky cards and on the underside of the lower leaves of the plants in the greenhouse.
  • The biological control treatments arrived on Tuesday.  The Encarsia formosa for whiteflies, Hypoaspis miles for fungus gnat larvae and thrips pupae were put out into the crop to help manage the pest pressures in the greenhouse.
  • The crop heights are within an acceptable range and it looks like we are ready to start black out right on schedule next week!  

Some of the students have started to space their cultivars since the vegetative growth is started to touch the plants surrounding it. The students spaced the poinsettias on 13cm-15cm centers. This will be their final spacing until sales. Another point worth mentioning is that students will attach their plants to a centralized drip system. This piece of technology will decrease the amount of labour required for watering events, which was historically done manually. By watering all the plants at the same time this will help create a uniform crop.

Greenhouse Update

Sept 26 High: 25, low 21 Mean humidity: 63%Weather rain
Sept 27Spot watered Titan Red with Mg Spot Watered Titan White with Mg.  Titan Pink and Mirage Red OK Wet floors: 10:20 am 1:30, 3:50.   Irrigation lines put out had to move some of the plants.  Tried to keep them in relatively the same orderHigh: 27, low 20 Mean humidity: 60%Weather Variable.  Mix of sun and rain.
Sept 28Plants have begun to be spaced.  Biobest beneficial insects have arrived.Zone 4: High: 27, low 19 Mean humidity: 60%   Zone 5: High   32, Low18 Mean Humidity 40%Weather sun part cloudy, cloudy in afternoon.
Sept 29Spacing of Titan Pink and Mirage Red into Zone 5 Titan White watered (most of crop some still wet) with Mg Floors wet 3:45pmZone 4: High 22, Low 19 Mean Humidity: 60%   Zone 5: High 21  , Low18 Mean Humidity 52%Weather cool raining
Sept 30 Zone 4: High 31 , Low 19 Mean Humidity 59%   Zone 5: High, 33,  Low19 Mean Humidity 49%Weather: Cloudy in morning sunny periods in afternoon
Oct 1Wet Floors 8:00 am Deployed Encarcia: 10 amZone 4: High   , Low   Mean HumidityWeather Cool, overcast in morning