SCROG Setup Guide: How to Run a Screen of Green in a 4x4 Tent
Step-by-step SCROG guide for cannabis — net height, mesh size, when to flip, how to weave, and real yield comparisons versus no training in a 4x4 grow tent.
What Is SCROG and Why It Maximizes Yield in a Fixed Space
SCROG (Screen of Green) is a training technique where a horizontal net or screen is placed over the canopy at a fixed height. As the plant grows, shoots are woven through the screen to create a flat, even canopy where every bud site receives equal light intensity.
In a 4x4 tent, an untrained plant wastes 40–60% of your light on lower bud sites that are too far from the light to produce dense buds. SCROG eliminates this waste by forcing every shoot to the same horizontal plane — directly under peak light intensity.
The yield improvement over no training is real and significant: most growers report 30–60% higher yield from their first SCROG versus their first untrained grow with the same genetics.
What You Need to Run a SCROG
The screen: A 4x4 ft net with 2-inch squares is the standard for a 4x4 tent. You can buy purpose-built SCROG nets or make your own from tomato cage wire, garden netting, or even paracord strung between poles.
Height of screen: Position the net 16–20 inches above your pot tops. This gives the plant 12–16 inches of growth to work with before hitting the screen, enough to develop strong lateral branching.
Number of plants: In a SCROG, one or two large plants often outperform four smaller ones. One well-trained plant with a long veg period can fill an entire 4x4 net. Use fewer, larger plants rather than many small ones.
Veg time: SCROG requires a longer veg period than standard growing. Plan for 6–10 weeks of veg (versus 4–6 weeks without SCROG) to allow the plant to fill the net before you flip to 12/12.
Step-by-Step SCROG Process
Step 1 — Veg and top your plant: Grow normally and top (remove the main growing tip) at the 3rd–5th node. This creates two main colas instead of one and encourages lateral branching that will fill the screen.
Step 2 — Install the screen at 16–20 inches: Once the plant is 12–14 inches tall, install the screen. The growing tips should just be poking through the squares.
Step 3 — Weave shoots, don't tuck: As shoots grow through the net, don't push them back down — weave them horizontally through adjacent squares. Each shoot should travel sideways until it has an empty square above it, then grow upward.
Step 4 — Fill the screen before flipping: Wait until the net is 70–80% full of evenly-distributed shoots before switching to 12/12. This is the most important rule of SCROG — flipping too early leaves the screen partially empty and wastes light.
Step 5 — Tuck for 2 weeks after flip: New growth will continue pushing upward for 2 weeks after the flip (the "stretch"). Continue tucking and weaving shoots to maintain the flat canopy. After week 2, stop tucking and let the shoots grow upward toward the light as buds develop.
Step 6 — Defoliate below the screen: Once canopy is set, remove all growth below the net. It receives no useful light and drains energy the plant could be putting into buds above the screen.
When to Flip to Flower with a SCROG
The single most common SCROG mistake is flipping to 12/12 too early. Growers see some growth in the net and get impatient, but 30–50% fill at flip means 30–50% wasted potential.
Target: 70–80% net coverage before flipping.
Remember that the plant will grow significantly during the first 2 weeks of flower (the stretch). A plant that fills 70% of the net at flip will typically fill 90–100% by the end of the stretch.
For a 4x4 net (16 sq ft), rough fill targets by plant count:
- 1 plant: 8–10 weeks veg before flip
- 2 plants: 6–8 weeks veg before flip
- 4 plants: 4–6 weeks veg before flip
SCROG Yield vs. No Training: Real Numbers
Growing the same genetics, same light, same medium:
| Training Method |
4x4 Yield (Beginner) |
4x4 Yield (Intermediate) |
Veg Time |
| No training | 3–6 oz | 6–10 oz | 4–6 weeks |
| LST only | 5–9 oz | 9–14 oz | 4–6 weeks |
| Topping + LST | 6–10 oz | 10–16 oz | 5–7 weeks |
| SCROG | 8–13 oz | 14–22 oz | 7–10 weeks |
SCROG adds cycle length (more veg time) but returns more yield per gram of electricity consumed. Use our
Yield Calculator to model SCROG vs LST for your specific setup.
Frequently Asked Questions
How high should a SCROG net be?
Position your SCROG net 16–20 inches above your pot tops. This gives the plant enough vertical space to develop branching before hitting the screen. If placed too low (under 12 inches), branches can't develop properly. Too high (above 24 inches) and you lose the canopy-evening benefit.
How many plants for SCROG in a 4x4?
1–2 plants is ideal for SCROG in a 4x4. One well-trained plant with 8–10 weeks veg can fill a 4x4 net completely. Two plants with 6–8 weeks veg work well. More plants means less veg time but similar final yield — the net, not the plant count, determines your canopy.
Can you SCROG autoflowers?
SCROG is challenging with autoflowers because you can't extend veg time — they flower on their own schedule. Use a low net (12–14 inches) and begin weaving shoots very early (week 2–3). Many growers prefer LST for autoflowers since it doesn't require timing the net fill before a set flip date.
When do you stop tucking in a SCROG?
Stop tucking approximately 2 weeks after flipping to 12/12. This is when the stretch typically ends and buds begin forming. Continuing to tuck after this point stresses the plant unnecessarily and can damage bud sites. Let the shoots stand upright once flowering is clearly established.
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