The ready signal
Leaves
Firm, turgid leaves plus fresh growth mean roots have settled
Light
Turn veg lighting to its full intended level
Formula
Switch toward a grow ratio near 3-1-2, 4-2-3, or 5-3-3 with micronutrients
Duration
Keep a high-nitrogen program until you change the light schedule for flower
Indoor vs outdoor timing
Indoor
You can start veg whenever the room is ready because you set day length
Heat and bugs
Some climates make summer indoor runs harder. Growers then hold mothers or clones and restart in fall
Outdoor soil
Wait until soil 3 inches (7.5 cm) down hits about 65 F (18 C) in the afternoon and stays above about 50 F (10 C) at night
Seed in ground
Best when night soil stays above about 60 F (15 C). Colder soil wets the seed but delays the sprout and invites fungi
Strength and water quality
Meter
About 1,000 ppm or EC 2.0 mS is a normal soluble-fertilizer target. If tap water is already 250 ppm, add fertilizer only up to that 1,000 ppm total
pH
Adjust toward 5.8 to 6.4 if the mix is running high or low
Milder
Use the weaker side of a label when unsure. Test a friend's odd recipe on one plant first
Hard water
Chlorine, chloramine, or very hard water can fight a fertilizer. Rainwater is a soft option
Brand fit
The same bottle can shine in one water and fail in another. Compare in your room, not on a forum
Leaf care while they grow
Dust
Mist every 2 to 4 weeks even if you are not foliar feeding, so dust does not coat the canopy
Timing
Spray at the start of the light cycle so leaves dry before lamps get hot
HID
Do not spray toward hot bulbs. Wipe any splash off a glass plate
Late flower flavor
The book notes a final week of plain water can reduce a green, chemical taste. That is a finish step, not a veg habit