Marijuana Pot Plants
How Do You Prune Marijuana Plants
(Q) I've tried to read everything on pruning and I
still don't get it. My plants are almost a month old, have three and
four sets of leaves and seem very healthy.
(A) First off, you might not have to prune them.
Second, leaves are not usually the purpose or the target of
pruning.
Third, knowing why you prune, and what happens when you do so will
probably answer all the rest of the questions.
You Prune For Two Reasons:
1) To control the upward or outward growth of your plants. In other
words to keep them short.
2) To promote node sites (or bud sites). In other words to create
more branches (growing tips).
When you look at the mainstem of the plant and how the leaves grow
from it, you will find it will be identical to any branch that grows
from it, or any branches that grow from them, etc.
So any reference I make to the mainstem here, holds true for any
branches, or any branches that grow from those branches, etc.
The point at where a leaf joins the mainstem (or branch) is the
node, at the node and just above the leafs' stem (petiole) you will
find a **bud**.
This bud will become a branch. Under the right conditions branches
will grow. Now, keep in mind that some varieties of plants are good
branchers, some are not.
Now let's assume the reason we're pruning is #2 above, to promote
node sites or branching. If you cut the top of the mainstem off then
look at the plant, there will be some leaves and associated nodes.
Since the top of the plant is gone, the growth energy that would go
there is now going to the remaining nodes because it has nowhere else
to go.
What you did by topping the plants was to FORCE growth at the nodes
thus promoting branching. The nodes nearest the light will grow the
fastest. You would do this if you don't want a plant to grow too tall,
but would rather want it to grow out.
If this is your first crop you'll understand much better what you
want once you've watched a plant through its entire life cycle.
If you topped the plant for reason #1, all the above would still
occur as a by-product, and most likely you would have to deal with the
top branches eventually becoming too tall.
(Q) Where exactly do I make the cuts?
(A) Appx 1/4 to 1/2 inch above the node that will
remain on the plant.
For cutting off leaves, cut them midway on the petiole.
(Q) Which set of leaves do I cut?
(A) You don't cut leaves off, you're just using
the leaves as an easy way to identify the nodesites. I believe every
leaf feeds energy to its nodesite, cut off the leaf and the branch at
that nodesite may not develop as expected.
(Q) And why am I cutting them?
(A) Usually you don't cut leaves off unless there
dying, or you have a big fat juicy bud that's trying to grow
underneath a big leaf. If the bud would benefit from the light the
leaf is shading, you decide which you'd rather have :-)
(Q) My logic would be the more leaves the better
opportunity for photosynthesis.
(A) As long as the light can get to them.
The only leaves that are going to use the light are the ones facing
the light. A few leaves deeper into the canopy and the extra leaves
wont do you any good.
HID lights penetrate deeper into the canopy than fluorescent.
Side lit systems like the phototron require you to prune to promote
branching *AND* to remove larger leaves that tend to grow nearest the
lights in order for direct light to benefit the newer inner branches.
The main reason this works in a phototron is the side lightings
ability to get under leaves that want to grow horizontally. Without
removing leaves near the light the trons fluorescent wouldn't
penetrate.
Top lit systems depend on light penetration qualities of the lamp
going through and around the leaf to do this.
I'd say a top lit garden would have enough leaves (full canopy)
when you don't see much light when looking up at the lights from the
bottom of the canopy.
A phototron is like a top lit garden only on its side and rolled up
into a circle. Its canopy are the sides of the unit.
One thing about pruning to remember is that one thick stemmed shoot
tip is being replaced by two or more much thinner shoot tips. Buds may
be more numerous but they will be smaller.
A pruning rule of thumb: The thinner the shoots, the smaller the
fruits.
(Q) I have seven plants and plenty of room .
Thanks in advance.
(A) As I said, you might not have to prune.
It wouldn't be a bad idea to do it on one plant just to get the
experience. Just be prepared for a shorter bushier plant than the
rest.
In the end you might find that 1 or 2 pruned plants can do as well
as the 7 you have now.