Mastering SCROG technology: Screen of Green for maximum yields

Screen of Green (SCROG) is one of the most effective yield enhancement techniques for cannabis:

**SCROG basic principle:**

Plants are fed horizontally through a grid, which ensures that all shoots receive the same amount of light and more flowering sites are created.

**SCROG setup preparation:**

*Mesh material:*

- Mesh size: 5x5cm or 7.5x7.5cm

- Materials: plastic mesh, wire mesh, bamboo mesh

- Height: 20-30cm above pots

- Stability: Must support plant load

*Frame construction:*

- PVC tubes or wooden slats

- Adjustable height recommended

- Easy disassembly for harvesting

- Stable attachment to the tent/room

*Number of plants:*

- 1-2 plants per m² optimal

- More growing time required

- Fewer plants = more yield per plant

- Space for horizontal spreading

**SCROG version:**

*Vegetative phase:*

- Grow plants up to 15-20cm above trellis

- Carefully bend shoots under trellis

- Never break or damage

- Even distribution is important

*Weekly training:*

- Guide new shoots continuously under trellis

- Thin out overcrowded areas

- Remove weak shoots

- Aim for uniform height

*Pre-flower phase:*

- Last 1-2 weeks before flowering

- Finalise positioning of all shoots

- Remove lower branches without light incidence

- Grid should be 70-80% full

**Flowering stage management:**

*Early flowering (week 1-3):*

- Continue light training

- Use the stretch phase

- Distribute shoots evenly

- No more hard bends

*Mid bloom (week 4-6):*

- Stop training completely

- Support only

- Support heavy blooms

- Ensure air circulation

*Late flowering (week 7+):*

- Use trellis as support

- Secure heavy colas

- No more manipulation

- Harvest preparation

**Optimisation strategies:**

*Light efficiency:*

- All flowering areas equally far from the light

- No shaded areas

- Light penetration maximised

- Uniform illumination

*Ventilation:*

- Good air circulation under grilles

- Mould prevention important

- Place fans strategically

- Control humidity

*Nutrient adaptation:*

- More flowers = higher demand

- More fertilisation necessary

- Calcium/magnesium important

- Use bloom booster

**Common SCROG mistakes:**

*Grid too early:*

- Plants too small

- Insufficient vegetation period

- Weak structure

- Low yields

*Overcrowding:*

- Too many shoots per area

- Poor air circulation

- Lack of light in lower areas

- Danger of mould

*Uneven distribution:*

- Concentration on individual areas

- Wasted potential

- Uneven flower development

- Sub-optimal yields

**Variety-specific adaptations:**

*Indica varieties:*

- Compact growth

- Less vegetation time

- Dense trellis filling

- Earlier flowering

*Sativa varieties:*

- Allow for more stretch

- Longer vegetation period

- Larger mesh size

- Later in flowering

*Autoflower:*

- SCROG more difficult

- Less training time

- Light LST preferred

- Shorter time window

**Yield