Professional Marijuana Grower March-April 2018 Issue | Page 38

Feature Article
by Andrew Taylor
Transitioning to the
Vegetative Phase of
Plant Growth
Steps to Hardening-off & Transplanting
The ability to move your cuttings or seedlings seamlessly from stage
to stage without stressing them out is an important key to achieving opti-
mal yields. Extra care during the early days will pay massive dividends
later on.  Growers need to be particularly aware of sudden changes in
humidity, temperature, light intensity and nutrient concentration.
Growing Freshly Rooted Cuttings (Hardening Off)
1. Opening up propagator lid vents gradually will help wean your root-
ed cuttings off their high humidity environment and prepare them for life
in the main grow room. This process should be done over a few days.
TIP: Eventually placing the propagation lid on an angle
will provide a temperature and humidity that is ‘clos-
er’ to the eventual grow room environment.
2. Air-pruning: Placing your nursery pots or propaga-
tion blocks on a mesh and raising them slightly off the
bottom of the tray will help your young plants to de-
velop better initial root structures—a technique known
as ‘air pruning’. Air pruning dehydrates and kills any
roots that try to grow beyond the propagation block (or
pot).  This is beneficial because it promotes root growth
within the block itself. A block which is fully colonized
is more likely to survive planting out into the larger
system and provide rapid growth into the vegetative
phase.
3. Do not over-water a fresh transplant. Simply making
sure the surrounding medium is moist will encourage
the roots to explore.
TIP: Make note of how heavy plants feel when wa-
tered.  Then recheck their weight daily – if they still feel
heavy then do NOT water them.
Moving to Vegetative Phase
When are plants ready for transplanting?
1. Clones need to be fully hardened off. Test their ca-
pacity to withstand the humidity and temperature used
38 • Professional Marijuana Grower
in the ‘vegetative phase’. Test for an hour or two to
begin with – gradual changes are key!
2. There must be plenty of air pruned roots on the
outside of the propagation cube. Do not leave it too
late or roots begin to circle the pot and it will become
root-bound. To inspect roots, gently lift the plant by
tapping or squeezing the pot on all sides – particularly
from beneath. If there are not many visible roots, or the
medium is falling apart, then the plant is not ready for
transplanting.
Keys for Transplanting
1. Try to stage pot size appropriately. A young plant
should not look ‘lost’ in a large pot. Use an intermedi-
ate size and allow the roots time to fully colonize the
entire medium available to them before replanting it
into a larger pot. Transplanting to an over-sized pot will
discourage roots from searching for water. It will also
cause the outer medium to become water-logged and
prone to water borne diseases such as pythium.
2. Fabric, breathable pots are highly recommended for
use with coco coir or soil. Choose pots with a low, wide
form. This will, in turn, encourage squat, wide plants
– especially when this technique is combined with low
stress training (LST) techniques.
March/April 2018