Cannabis SCROG Setup: Screen Height, Mesh Size, Training

What a SCROG setup is

SCROG means Screen of Green. A mesh screen sits above the plants. Shoots are pulled under the screen and spread into open squares. Each square holds one top. The result is a flat canopy. Light hits every top at the same distance. A flat canopy uses the grow light footprint better than an untrained plant of the same age.

cannabis scrog setup yield increase

Parts

• Screen: 8 to 10 in (20 to 25 cm) above the medium surface.
• Mesh: 2 to 4 in (5 to 10 cm) squares. Wider squares let shoots slip back. Narrower squares make tucking slow.
• Frame: PVC pipe, wood, or a tent corner kit. The frame holds the weight of the canopy at week 6 of flower.
• Ties: soft plant ties or coated wire. Bare wire cuts stems.

Screen height

Measure from the top of the soil or coco, not from the floor. A screen 8 in above the medium leaves room for watering and for stem growth under the mesh. A screen set at 12 in or more lets shoots grow long before tucking starts. Long shoots bend and crack. Set the screen before the plant reaches it, then raise or lower the frame as needed.

Cannabis Scrog Setup Cost

Plant count and pot size

One plant fills a 2 x 2 ft (0.6 x 0.6 m) screen in a 5 to 7 gallon pot. Two plants fill a 3 x 3 ft screen faster and cut veg time. More than four plants in a 4 x 4 ft space crowds the mesh and blocks airflow under the canopy.

cannabis scrog setup guide

Steps

1. Grow the plant to 5 or 6 nodes. Top above the 5th node. Two shoots grow from that cut.
2. Top each new shoot one more time if the screen is larger than 2 x 2 ft. Four to eight tops start the screen.
3. Place the frame 8 to 10 in above the medium.
4. Pull the tallest shoot under the mesh and set it in the next open square. Aim it toward the edge of the frame.
5. Repeat every 2 to 3 days during stretch. Move shoots to outer squares. Keep the canopy level.
6. Remove shoots that stay under the screen. They get no light and take nutrients.

Fill the screen, then flip

Fill 70 to 80 percent of the squares before changing the light to 12 hours on and 12 hours off. Flower stretch adds 50 to 100 percent more height in the first 2 to 3 weeks. Tuck shoots during that window. The screen fills by week 3 of flower. Do not tuck after week 3. Stems harden and buds bruise.

Airflow and defoliation

Remove fan leaves and small shoots below the screen at day 1 and day 21 of flower. A dense canopy holds moisture. Add one oscillating fan above the screen and one below it. Keep the under-canopy clear to the pot rim.

Common errors

• Screen set too high, so shoots grow long before tucking.
• Flipping to 12/12 with 40 percent of squares empty.
• Mesh squares under 2 in, which slow tucking.
• Leaving shoots under the screen.
• No fan below the screen.