How High Should a SCROG Net Be Above Plants?

The first SCROG net goes 8 to 12 inches above the top of the growing medium. A second net, when you run one, goes 6 to 12 inches above the first. That range wins for most grows because it balances the three criteria that decide screen height: how far the plant stretches after the flip to flower, how much headroom sits between the canopy and the light, and how much training you did before flower with topping and low stress training. Measure from the surface of the soil or coco, not from the floor, and keep the mesh squares between 4 and 6 inches.

DIY Cannabis SCROG Screen Kit: Build, Size, Train

Why 8 to 12 inches is the default

Two forces set the floor and ceiling of that range. Below the screen you need room to reach in with both hands, tuck a shoot, and pull a dead leaf without snapping a stem. Above the screen you need room for the plant to double in height during stretch and still finish 12 to 18 inches under the light. A net at 8 to 12 inches above the medium leaves space for both.

when to start scrog training cannabis

Pros

• Fits the pot heights most growers already use, from 3 gallon fabric pots to 7 gallon containers.
• Works with one net or two, so you can add support later without moving the first screen.
• Leaves enough stem under the screen to bend shoots sideways without creasing them.

Cons

• A tall pot plus a 12 inch gap puts the canopy higher than some short tents allow.
• Strains with heavy stretch can still push past the second net in the first two weeks of flower.

Use it if: you grow photoperiod plants in a tent 5 feet tall or more and plan to top once or twice before the flip.

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Low net at 6 to 8 inches above the medium

A low screen forces horizontal growth early. Shoots hit the mesh while they are still soft, which makes tucking easy and spreads the canopy wide instead of tall.

Scrog vs Sog for Cannabis Yields

Pros

• Keeps total plant height down, which protects you from light burn in a short tent.
• Fills the screen fast on compact indica-dominant plants and autoflowers.
• Short stems under the mesh stay thick and hold heavy colas with less flop.

Cons

• Cramped space under the screen makes watering, defoliation, and inspection awkward.
• Less stem length to work with, so a shoot that breaks has fewer backup nodes.
• Weak for stretchy sativas, which can blow through a low screen and into the light.

Use it if: your tent is under 5 feet tall, you run autoflowers, or you grow in short containers and need every inch of vertical room.

High net at 12 to 18 inches above the medium

A high screen lets the plant build vertical stem before you start training. You get a taller main stalk with more nodes to spread across the mesh.

Pros

• Suits sativa-dominant plants that stretch two to three times their flip height.
• Wide open working space under the net for pruning and watering.
• Lets you run a longer veg cycle and a bigger root zone before the screen matters.

Cons

• Longer veg time is needed to fill the same screen area.
• Bare stem below the net does not produce buds, so that vertical space is spent on structure.
• Plants that finish tall need a second net and careful light clearance planning.

Use it if: you grow tall sativas, run a room with 7 feet of headroom or more, and can veg for an extra week or two.

Second net at 6 to 12 inches above the first

The second screen is a support layer, not a training layer. It catches colas as they stack and keeps them from leaning into each other late in flower.

Pros

• Holds heavy top colas upright without tying each branch.
• Spreads the upper canopy so light reaches more bud sites.
• Worth the effort on any plant that stretches past 1.5 times its flip height.

Cons

• Adds a barrier between you and the canopy at the messiest point of the grow.
• Can trap humid air if the room has weak airflow.

Use it if: you grow stretchy sativas or large plants with long colas. Skip it on compact indicas and autoflowers that finish short.

Adjust the height for strain stretch

Stretch is the one variable that changes the answer most. Indica-dominant plants often finish near 1.5 times their flip height. Sativa-dominant plants and many hybrids reach two to three times that height. Plan the first net at 8 inches and the second at 10 to 12 inches above the first when you expect heavy stretch. Plan a single net at 10 to 12 inches when you expect little stretch.

Pros of tuning to stretch

• Keeps the top of the canopy in the light sweet spot instead of pressed against the fixture.
• Reduces the amount of late super cropping and bending you have to do.

Cons of ignoring it

• Heavy stretch runs into the light and forces you to raise it above the rest of the room.
• Short plants under a high net leave most of the screen empty and waste light.

Measure from the medium, then check light clearance

Set the tape on the surface of the soil or coco, not the floor and not the rim of a tall pot. A 5 gallon fabric pot can sit 12 inches tall, so measuring from the floor adds a foot of error to your plan. Once the net is level, measure from the top of the net to the lowest point of the light. Subtract the stretch you expect and confirm the finished canopy still sits 12 to 18 inches below the fixture.

When to hang the net and start tucking

Hang the net before the shoots reach it so you never have to force branches through. Veg until shoots sit 4 to 6 inches above the mesh, then tuck each one back under and guide it toward an open square. Keep tucking through the first two weeks of flower. Stems harden after that, and bending them then risks a break.

Mistakes that cost weight

• Measuring net height from the floor instead of the medium.
• Hanging the net so high that plants stretch upward to reach it.
• Using mesh with squares smaller than 4 inches, which traps shoots and blocks airflow.
• Tucking in week four of flower when the stems have gone woody.
• Running a second net with no plan for how you will reach the plants underneath it.

Which height fits your grow

1. Short tent, autoflowers, compact indicas: one net at 6 to 8 inches above the medium.
2. Standard 4x4 or 2x4 photoperiod grow: one net at 8 to 12 inches, or two nets with 8 to 10 inches between them.
3. Tall sativas in a room with 7 feet of headroom: first net at 8 to 10 inches, second net 10 to 12 inches higher.

Healthy genetics and a steady light schedule matter more than a perfect measurement, but getting the screen height right early saves you from bending, tying, and raising lights in week five of flower.