Stage targets

Climate, light and root-zone targets by growth stage. Every cell shows its evidence grade and links its sources.

MetricImperial

Targets are typical research and extension ranges, not guarantees; cultivars differ. Grades: strong (consistent peer-reviewed evidence), moderate (peer-reviewed, limited studies or cultivars), extension (university extension or industry-standard guidance), community practice (widely used by growers, not tested in trials), contested (studies disagree), folklore (repeated, but the evidence does not support it). Numbered chips open each source. Flower values apply through late flower unless the library has a late-flower-specific value.

Cited growth targets by stage. Each value shows its evidence grade and numbered source links.
Parameter	Propagation	Vegetative	Flower	Late flower	Drying & cure
Day temperature	24–26 °CModerate Sources:1	24–28 °CCommunity practice Sources:1 2	24–28 °CModerate Sources:1 2 3 4 5 ≤ 28 °C (day)Moderate upper limit Sources:1 2	No cited target	18–21 °CExtension common practice · air drying Sources:1 15–25 °CModerate industrial study · tray/hang air drying Sources:1 15.6 °C (60 °F) at 60% RHCommunity practice community rule · air drying Sources:1
Night temperature	No cited target	20–24 °CCommunity practice Sources:1 2	18–22 °CModerate Sources:1 2 3	No cited target	No cited target
Relative humidity	70–95%Community practice Sources:1 2 3 70–95%Community practice under dome, week 1 Sources:1 2 3	55–70%Community practice Sources:1 2	40–60%Moderate Sources:1 2 3 4 5 ≤ 70%Moderate upper limit Sources:1	No cited target	50–55% RHExtension common practice · air drying Sources:1 40–60% RHModerate industrial study · tray/hang air drying Sources:1
Leaf VPD	0.4–0.8 kPaExtension Sources:1 2	0.8–1.2 kPaCommunity practice Sources:1 2	1–1.5 kPaModerate Sources:1 2 3 4	1.2–1.6 kPaCommunity practice Sources:1 2	No cited target
PPFD	100–250 µmol/m²/sModerate Sources:1 2 3 100–250 µmol/m²/sModerate Sources:1 2 3	400–900 µmol/m²/sModerate Sources:1 2	600–1,800 µmol/m²/sStrong Sources:1 2 3 4 5 6	No cited target	No cited target
DLI	5–15 mol/m²/dModerate Sources:1 2 3	26–52 mol/m²/dModerate Sources:1 2	26–78 mol/m²/dStrong Sources:1 2 3	No cited target	No cited target
Photoperiod	No cited target	18–20 hModerate Sources:1 2 3	12 hStrong standard 12/12 Sources:1 2 3 13 hModerate 13/11 variant Sources:1 2 14 hModerate 14/10 variant Sources:1 2 3 10–11 hFolklore 11/13 or 10/14 'finish faster' Sources:1 2 3	No cited target	No cited target
CO₂ (lights on)	No cited target	800–1,200 ppmModerate Sources:1 2 3 4 5	800–1,200 ppmModerate Sources:1 2 3 4 5	800–1,200 ppmModerate Sources:1 2 3 4 5	No cited target
Feed EC	1.2 mS/cmModerate cuttings · peat pellets Sources:1 2	No cited target	1.5–2.5 mS/cmModerate soilless or hydroponic Sources:1 2 3 ≤ 4 mS/cmModerate upper limit · hydroponic Sources:1 2	No cited target	No cited target
Root-zone pH	All growth stages 5.8–6.2 pHExtension soilless (peat/coir) Sources:1 5.5–6.5 pHExtension hydroponic Sources:1 2				No cited target
Water activity	No cited target	No cited target	No cited target	No cited target	0.55–0.65 a_wExtension dried flower Sources:1

Propagation

Day temperature: 24–26 °CModerate
Sources:1
Relative humidity: 70–95%Community practice
Sources:1 2 3
70–95%Community practice
under dome, week 1
Sources:1 2 3
Leaf VPD: 0.4–0.8 kPaExtension
Sources:1 2
PPFD: 100–250 µmol/m²/sModerate
Sources:1 2 3
100–250 µmol/m²/sModerate
Sources:1 2 3
DLI: 5–15 mol/m²/dModerate
Sources:1 2 3
Feed EC: 1.2 mS/cmModerate
cuttings · peat pellets
Sources:1 2
Root-zone pH: 5.8–6.2 pHExtension
soilless (peat/coir)
Sources:1
5.5–6.5 pHExtension
hydroponic
Sources:1 2

Vegetative

Day temperature: 24–28 °CCommunity practice
Sources:1 2
Night temperature: 20–24 °CCommunity practice
Sources:1 2
Relative humidity: 55–70%Community practice
Sources:1 2
Leaf VPD: 0.8–1.2 kPaCommunity practice
Sources:1 2
PPFD: 400–900 µmol/m²/sModerate
Sources:1 2
DLI: 26–52 mol/m²/dModerate
Sources:1 2
Photoperiod: 18–20 hModerate
Sources:1 2 3
CO₂ (lights on): 800–1,200 ppmModerate
Sources:1 2 3 4 5
Root-zone pH: 5.8–6.2 pHExtension
soilless (peat/coir)
Sources:1
5.5–6.5 pHExtension
hydroponic
Sources:1 2

Flower

Day temperature: 24–28 °CModerate
Sources:1 2 3 4 5
≤ 28 °C (day)Moderate
upper limit
Sources:1 2
Night temperature: 18–22 °CModerate
Sources:1 2 3
Relative humidity: 40–60%Moderate
Sources:1 2 3 4 5
≤ 70%Moderate
upper limit
Sources:1
Leaf VPD: 1–1.5 kPaModerate
Sources:1 2 3 4
PPFD: 600–1,800 µmol/m²/sStrong
Sources:1 2 3 4 5 6
DLI: 26–78 mol/m²/dStrong
Sources:1 2 3
Photoperiod: 12 hStrong
standard 12/12
Sources:1 2 3
13 hModerate
13/11 variant
Sources:1 2
14 hModerate
14/10 variant
Sources:1 2 3
10–11 hFolklore
11/13 or 10/14 'finish faster'
Sources:1 2 3
CO₂ (lights on): 800–1,200 ppmModerate
Sources:1 2 3 4 5
Feed EC: 1.5–2.5 mS/cmModerate
soilless or hydroponic
Sources:1 2 3
≤ 4 mS/cmModerate
upper limit · hydroponic
Sources:1 2
Root-zone pH: 5.8–6.2 pHExtension
soilless (peat/coir)
Sources:1
5.5–6.5 pHExtension
hydroponic
Sources:1 2

Late flower

Leaf VPD: 1.2–1.6 kPaCommunity practice
Sources:1 2
CO₂ (lights on): 800–1,200 ppmModerate
Sources:1 2 3 4 5
Root-zone pH: 5.8–6.2 pHExtension
soilless (peat/coir)
Sources:1
5.5–6.5 pHExtension
hydroponic
Sources:1 2

Drying & cure

Day temperature: 18–21 °CExtension
common practice · air drying
Sources:1
15–25 °CModerate
industrial study · tray/hang air drying
Sources:1
15.6 °C (60 °F) at 60% RHCommunity practice
community rule · air drying
Sources:1
Relative humidity: 50–55% RHExtension
common practice · air drying
Sources:1
40–60% RHModerate
industrial study · tray/hang air drying
Sources:1
Water activity: 0.55–0.65 a_wExtension
dried flower
Sources:1

Ask Grow Guru about thisQuestions about stage targets? Answers come from the same cited library.