Quick answer
Start the screen when the plant has 4 to 6 nodes. That is 3 to 5 weeks from seed or 2 to 3 weeks from a rooted clone. Set the net 8 to 20 inches above the pot rim. Tuck branch tips through the mesh during veg. Flip the light to 12/12 when the screen is 70 to 75 percent full.
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Screen height
A net at 12 inches above the medium fits most tents. Lower nets at 8 to 10 inches suit short indica plants and short tents. Higher nets at 16 to 20 inches suit sativa plants with long spaces between nodes. Leave room for your hands and a watering can under the net.
Plant size and node count
A plant with 4 to 6 nodes has enough stem to bend without snapping. Top the plant above the 3rd to 5th node at that point. Two tops become four. Four become eight. More tops fill the mesh with fewer plants.
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Start tucking when a branch tip reaches 2 to 4 inches above the net. Pull the tip down and slide it under the nearest square. Point the tip at an empty square.
When to flip to flower
Flip to 12/12 when the screen is 70 to 75 percent full. Plants stretch 50 to 100 percent in the first 2 to 3 weeks of flower. Indica plants stretch less. Sativa plants stretch more. A screen at 100 percent fill on flip day will overgrow the tent.
Autoflowers
Autoflowers flower on a fixed schedule, 3 to 5 weeks from sprout. There is no veg flip to control. SCROG on autoflowers gives mixed results. Low-stress tucking can work if the plant is large at week 3. Topping an autoflower can stall growth.
Grid size
Square size runs from 2 by 2 inches to 4 by 4 inches. 3.5 by 3.5 inches is a common choice. Thin wire cuts stems. Use soft string or coated wire.
Lower growth
Remove shoots below the net that do not reach a square. This sends growth to the canopy. Do this at week 2 of flower, not before.
Steps
- Week 1 to 2 of veg: no net needed.
- Week 3 to 5: install the net at 8 to 20 inches.
- Top above the 3rd to 5th node.
- Tuck tips under the mesh every 2 to 3 days.
- Fill the screen to 70 to 75 percent.
- Flip to 12/12.
- Keep tucking for the first 2 weeks of stretch.
- Stop tucking at week 3 of flower.