Another commentary on an exam question from June 2019, this one from Unit 2014 in Plant Growth:
a) Name THREE types of commercial propagation facility used to grow plants. 3 marks
b) Describe how to manage the environment of ONE of the propagation facilities named in a), to encourage the rooting process. 3 marks
c) State the aftercare of vegetatively propagated plants after removal from the propagation facility. 4 marks
This question relates to the following part of the syllabus:
4.3 Describe the propagation facilities and aftercare for vegetative propagation. State the environmental conditions required for EACH method of propagation described in 4.2. State a propagation facility for rooting EACH of the types of cutting described in 4.2 (examples to include a heated propagator, mist bench, cold frame, the open ground). Describe how to manage the environment, to include: temperature, moisture/drainage, airflow, relative humidity to encourage the rooting process. State how to avoid damage from ONE NAMED pest and ONE NAMED disease during the rooting process. Describe the aftercare of vegetatively propagated plants (from 4.2), including the removal of diseased, dead material, feeding, hardening off (where appropriate), potting off (where appropriate).
For part a), the syllabus doesn’t specifically mention commercial propagation, but does include some propagation facilities that would be suitable. This is really pointing you in the direction of avoiding stating simple home facilities that may be used, such as a polythene bag over a flower pot.
The examiners’ comments include some facilities that aren’t listed in the syllabus, such as fogging unit and growing room for tissue culture. Those on the syllabus that were suitable included mist propagation unit, cold frame and heated propagator.
For part b), stop and think which type of propagation facility you would find easiest to write about. Suggested answers included:
Cold frame and outdoor polythene tunnel -ensure that the facilities are clean and the growing media is weed free. The soil can be ameliorated with grit or a suitable growing media to improve drainage and aeration.
Other points that were relevant in different facilities include controlling the bottom heat by a thermostat and maintaining appropriate moisture levels, e.g. by mist nozzles, shading to reduce light levels and temperature.
For part c) it is important to read the question carefully and note that it refers to looking after the plants after they have been moved out of whatever propagation facility they were in. Also, look at the marks allocated and make sure include enough information for the 4 marks.
The examiners’ comments suggest the following:
· Weaning plants from the propagation environment
· Removal of dead or diseased material
· Foliar feeding if required
· Hardening off plants
· Potting off the plants if required
· Use of crop protection measures if required
· Watering (close attention required)