But if the shade of green is just a little pale or a little off, the plant could be telling us there’s something we need to pay attention to. For instance, it could be indicative of pH issues in the media, so the plant can’t access the full suite of assimilates or nutrients that it needs.
It can also be a very early sign of a deficiency. Usually, you won’t see the full symptoms until several weeks after the problem has started. So best to catch them as early as possible.
That’s why I think it’s a good practice to take daily crop walks. Whether that’s the Head Grower, or delegated to competent staff that report to the Head Grower, it’s vital to get good visual once-overs of each stage of growth of the plants.
These routine observations help you make sure the plants are, at a basic level, healthy and perky at each stage of growth.
They also make it easier to notice when something starts to change.
Key Takeaways
Know What Healthy Plants Look Like
As a general rule, you’re looking for healthy, verdant green, blemish-free plants. And when I say blemish-free, I mean looking at the leaves as sums of individual leaflets. No fading in interveinal areas; no mottling or spots; no issues along the margins or outer edges of each leaflet.
There are some nuances to this, but if the plants look free and clear of the above indicators, it’s reasonable to assume balance between assimilation and environmentals.
Healthy leaf posture is important, too. You want to see signs that the plant is growing vigorously, but not too much.
Kind of that Goldilocks pocket of healthy leaf posture and growth.
Knowing what that looks like gives you something to compare to during those daily crop walks. You aren’t waiting for a plant to look compromised . You’re looking for the subtle changes that tell you something isn’t quite right.
Subtle Changes Can Signal a Problem
A simple lack of vigor can be indicative of something that can be fixed pretty quickly.
Examples include too high of electrical conductivity (EC) in the media for the given stage of growth. Or plants being too dry and near or at their wilt point. The plants may have missed a fertigation event or events. Maybe something failed among irrigation programming or infrastructure.
It could also be light intensity. Maybe someone missed setting the lights at the appropriate height or the appropriate intensity, and the plants aren’t getting the daily light integral they need for sufficient growth.
The important part is noticing the change. What you see doesn’t necessarily tell you the cause.
The Same Sign Can Point to Different Problems
What you see in the plant doesn’t always point to one obvious cause.
Acute leaf posture can be indicative of too-dry conditions or an overly-concentrated root zone chemistry. Blemishes can point to root-zone chemistry imbalances, whether that be lockout or antagonisms simply due to too high of root zone EC or specific elemental deficiencies in the fertility program.
Droopy plants can be trickier because they can indicate overly dry or overly wet conditions. If the plants look droopy and sickly, but you pick up the pot or test the media with a probe and find it’s really saturated and kind of bogged down—or even has a funky smell—we’re oversaturated. The roots aren’t able to get the oxygen they need.
A droopy plant isn’t automatically a plant that needs more water. What you’re seeing is a signal to look more closely at plant health.
The plants talk to you. The job is to listen before a small change becomes a bigger problem.
Coming Up
In upcoming posts, I’ll dig deeper into what the canopy can tell you about an operation, how plant signals change through different stages of growth, and how to work backward from a plant health problem to figure out what’s actually causing it.
Led by founder Wally Daniel, Green Garden Consulting helps cannabis operators across North America and beyond improve plant vitality, streamline operations, and build stronger teams. We combine over 30 years of hands-on industry experience with plant science expertise to deliver results that last.