SCROG (Screen of Green) for Cannabis: When to Flip, How to Weave, and Whether It's Worth the Commitment

SCROG done right: the flip-timing rule (fill the screen 70-80%), the weave-and-tuck rhythm, SOG vs SCROG settled, and the honest commitment nobody warns you about.

A grower came in last spring frustrated that his SCROG had produced a lopsided, gappy canopy instead of the flat table of even colas he'd seen in photos. We asked when he flipped to flower. His screen had been maybe a third full, he'd gotten impatient and switched the lights, figuring the plants would "fill in." They did stretch, but unevenly and explosively, shooting some branches a foot above the net while leaving whole sections of the screen empty. By the time he tried to tuck them back, the stems were too stiff and the buds were already forming. The technique was fine. The timing was the whole problem. SCROG lives and dies on one decision more than any other, when you flip, and almost every guide is vague about exactly that.

SCROG, short for Screen of Green, is the technique that takes the flat canopy you start with topping and LST and locks it in with a net, producing the dense, even "table" of colas that fills a grow space and maximizes every watt of light. Done right it's one of the highest-yielding methods for a small indoor space. But it's also a real commitment, and most guides skip both the part that actually matters (flip timing) and the honest downside (once plants are woven into the screen, you can't move them until harvest). This guide covers both. It's a technique, so there's little to sell here beyond the net itself, mostly it's about getting the rhythm and the timing right.

The 30-Second Answer

• What it is: a horizontal net or screen placed above your plants; you weave and tuck branches under it through late veg so they grow sideways into a flat, even canopy instead of up into a few tall colas.
• Screen height: roughly 8 to 12 inches above the top of the pots, positioned in late veg once plants have a few nodes of branching.
• The key decision, when to flip: flip to 12/12 when the screen is about 70 to 80% filled. The flowering stretch fills the remaining 20 to 30%. Flip too early and the stretch overshoots unevenly; flip too late and you run out of vertical room.
• The honest catch: once branches are woven into the screen, the plants are locked in place until harvest, you can't move or rotate them. SCROG is a commitment, not a casual technique.

What SCROG Is and Why It Works

A net stretched horizontally above your plants becomes a training grid. As branches grow up and reach the screen, you weave them through the squares and tuck them back down sideways, so instead of one tall cola racing for the light, the plant spreads out and fills the screen with many growing tips, all sitting at the same height.

Why this matters comes down to light. With an untrained "Christmas tree" plant, you can only lower your light until it's close to the single top cola, everything below gets progressively less light and produces smaller, airier "popcorn" buds. A SCROG canopy turns the whole grow space into one flat table of tops, all at the optimal distance from the light. Every site on that screen gets strong, even light, so instead of one big cola and a lot of mediocre lower growth, you get a screen full of uniform, fat colas. That's where SCROG's big yields per square foot and per watt come from, it's not magic, it's filling your light's entire footprint with productive canopy.

SOG vs SCROG: Settling the Confusion

These two get mixed up constantly because the names rhyme, but they're different strategies:

• SCROG (Screen of Green) uses a screen to train a small number of plants to spread out and fill the space. Fewer plants, more training, longer veg. It's about maximizing each plant.
• SOG (Sea of Green) uses many small plants grown close together with little or no training, flipped to flower early so each produces one main cola. More plants, less training, shorter veg. It's about maximizing plant count.

The practical difference: SCROG is ideal when you're limited on plant count (legal limits, or you just want to run a few plants) but have time to veg and train. SOG suits growers who can run many plants and want a fast, hands-off turnaround. For most home growers working with a small number of plants in a tent, SCROG is the more relevant technique, and it's what this guide covers.

Setting Up the Screen

• Height: position the screen about 8 to 12 inches above the top of your pots. Lower fills the screen sooner; higher gives more under-net room but takes longer to fill.
• Net size: a roughly 2-inch square mesh is the standard, big enough to weave branches through easily, small enough to support the canopy.
• Material: elastic/soft trellis netting is easiest to work with and most common; rigid options (metal mesh, rope screens) give firmer control but are less forgiving. Whatever you use, anchor it securely to your tent frame or posts, it will hold real weight once the colas fatten.
• Coverage: the screen should span the area your light covers evenly. The goal is to fill that lit footprint, so size the screen to the light, not the other way around.

You'll want trellis netting and sturdy anchor points; we stock trellis netting and supports for exactly this.

The Weave-and-Tuck Rhythm

Once the screen is up and branches start reaching it, SCROG becomes a regular, gentle habit through late veg:

1. Let a tip grow a few inches above the net (about 2 to 3 inches / 5 to 8 cm).
2. Gently pull it back down below the screen and tuck it into the next empty square over, guiding it horizontally.
3. Repeat across the whole canopy, always moving growth from crowded areas toward empty squares, so the screen fills evenly from the center outward.
4. Keep the canopy flat. Anytime a tip shoots up, tuck it back under. You're weaving the plant into a level table, like training a vine along a trellis.

This is the same bending logic as LST (SCROG is essentially LST organized by a screen), so if you've read our LST guide, the gentle-bending technique carries straight over, just soften stiff stems first and bend gradually. Do your weaving while stems are still flexible.

When to Flip: The 70-80% Rule

This is the decision that makes or breaks a SCROG, and the one most guides leave vague. Here's the rule that would have saved the grower at the top of this article.

Flip to 12/12 when your screen is about 70 to 80% filled, not 100%, and not 30%. The reason is the flowering stretch: when you flip, photoperiod plants roughly double in height over the first 2 to 3 weeks of flower. That stretch fills the remaining 20 to 30% of your screen for you. So you flip with the screen mostly (but not completely) full, and the stretch finishes the job perfectly.

Get this wrong in either direction and you pay for it:

• Flip too early (screen barely full) and the stretch overshoots, branches blow past the net unevenly, you can't tuck them all in time, and you end up with a lopsided canopy and empty gaps, exactly what happened to our customer.
• Flip too late (screen 100% full before flipping) and the stretch has nowhere to go but up and out of your light's sweet spot, crowding the canopy and creating airflow and light problems.

So the discipline is: veg long enough to fill the screen to roughly 70-80% by weaving, then flip and let the stretch do the rest. This is why SCROG requires a longer, planned veg than an untrained grow, you're vegging until the screen is ready, not to a fixed date.

After the Flip: Tuck, Then Lollipop

The work isn't over at the flip, it transitions:

• Keep tucking through the stretch. For the first 1 to 2 weeks of flower, continue weaving the stretching shoots under and around the net to keep the canopy even. Stop once the stretch ends and buds start forming, you don't want to handle developing flowers.
• Lollipop below the screen. Once the canopy is set, remove the growth below the net, the small shaded branches and larfy lower buds that will never get light. This "lollipopping" redirects the plant's energy up into the fat colas on top of the screen instead of wasting it on popcorn below.
• Mind airflow and humidity. A dense SCROG canopy can trap humid, still air underneath, which invites bud rot. Good circulation under and across the canopy matters more in a SCROG than almost any other setup; our ventilation and airflow guide covers keeping air moving through a dense canopy.

SCROG + Topping + LST: How They Combine

These three aren't competing, they stack. The strongest canopies usually use all of them:

• Top early in veg to split the main cola into multiple growing tips, giving you more branches to fill the screen. See our topping guide.
• LST the branches outward to start spreading them before the screen even goes in.
• SCROG to lock it all in, the screen organizes and supports the flat canopy you created, and holds the colas up as they get heavy in flower.

You don't have to do all three, plenty of growers SCROG without topping, just bending the main stem and weaving. But topping plus LST plus SCROG together is how you get the textbook flat table packed with even colas.

The Honest Tradeoff: SCROG Is a Commitment

Here's the downside the seed-bank guides gloss over, and you should know it before you start. Once your branches are woven into the screen, the plants are physically locked in place. You can't move a plant to water it separately, rotate it for even light, isolate one that's showing a problem, or rearrange your tent. The whole grow is committed to the screen until harvest.

SCROG also takes consistent hands-on time through veg and early flower, the weaving and tucking is a regular habit, not a one-time setup. And it requires a longer veg than an untrained grow, since you veg until the screen fills rather than to a quick schedule.

None of this is a reason to avoid SCROG, the yield payoff is real, but it's a reason to go in clear-eyed. If you want flexibility (to move plants, run a short veg, or keep things low-effort), LST alone gets you most of the canopy benefit without locking you to a screen. SCROG is for the grower who wants maximum yield from a fixed space and is willing to commit the time and the layout to get it.

What We'd Tell You at the Counter

Flip at 70 to 80% screen fill, and let the stretch finish it. This one decision matters more than anything else in a SCROG. Too early and the stretch overshoots into a lopsided mess; too late and it grows out of your light. Veg until the screen is mostly full, then flip.

Weave gradually, keep it flat. Let tips clear the net a couple inches, then tuck them sideways into empty squares. It's the same gentle bending as LST, just organized by the screen. Soften stiff stems and never force them.

Lollipop after the canopy sets, and mind your airflow. Clear the shaded growth below the net so energy goes to the top colas, and keep air moving, a dense SCROG canopy is a bud-rot risk if the air under it goes still.

Know what you're committing to. Once they're woven in, the plants don't move until harvest, and the weaving is a regular habit. If that sounds like more than you want, LST alone is the lower-commitment path to a similar canopy. We'd rather you pick the method that fits how you actually want to grow than oversell you a screen. We don't upsell.

SCROG is the capstone of canopy training. It builds on our topping guide and LST guide (do those first), needs the airflow covered in our ventilation guide, and fits into the full timeline in our week-by-week grow guide.

Modern Farms stocks the trellis netting, tent supports, and the airflow and climate gear that a healthy SCROG canopy depends on, plus the meters to keep the plants in range while you train. If you're planning a SCROG for your space and want help sizing the screen to your light or timing your flip, we're happy to talk it through in person or by phone. We don't upsell.

This article is for informational and educational purposes only. Cannabis cultivation laws vary by state and locality. Grow only in accordance with the laws that apply to you, and where required, only as a licensed grower. Modern Farms sells equipment and supplies and does not provide legal advice.