Introduction: Why Growth Stage Management Matters

In vertical farming, every day counts. Understanding what your plants need at each stage — from germination to harvest — can be the difference between a mediocre yield and an exceptional one.

This guide walks you through the four key stages:

• Germination (Days 1-5)
• Seedling (Days 6-12)
• Transplanting (Day 13)
• Vegetative / Maturation (Days 14-25+)

Each stage has specific requirements for light, nutrients, temperature, and humidity. Follow this roadmap to maximize your harvest.

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Part 1: Germination (Days 1-5)

The germination stage is when your seed wakes up and sends out its first root (radicle) and shoot.

What’s Happening Inside the Seed

Process	Description
Imbibition	Seed absorbs water, swelling and cracking the seed coat
Enzyme activation	Stored food (starch, proteins) breaks down into energy
Radicle emergence	First root pushes out
Shoot emergence	First stem pushes up toward light

Optimal Conditions for Germination

Parameter	Recommendation	Why
Temperature	22-25°C (72-77°F)	Warmth speeds up enzyme activity
Humidity	80-95%	Prevents seed from drying out
Light	None or very low (5-10 µmol/m²/s)	Most seeds germinate in darkness
Growing medium	Rockwool, peat pellets, or sponge plugs	Holds moisture while allowing air flow
Water	pH 5.5-6.0, EC 0.5-0.8 mS/cm	Low nutrient concentration

Step-by-Step Germination Process

Day 1: Prepare Growing Medium

1. Soak rockwool cubes in pH-adjusted water (pH 5.5-6.0) for 1 hour
2. Gently shake out excess water (medium should be moist, not dripping)
3. Place cubes in seedling tray with humidity dome

Day 1: Sow Seeds

1. Drop 1-2 seeds per cube (depending on seed size)
2. Cover with a thin layer of vermiculite or close the cube hole
3. Mist lightly with water
4. Cover with humidity dome to maintain 85-95% humidity

Days 2-5: Monitor and Wait

• Check moisture daily — medium should stay damp
• Remove humidity dome briefly each day for fresh air
• Look for first signs of root emergence (typically day 3-4)

Common Germination Problems

Problem	Cause	Solution
No germination after 7 days	Temperature too low or seeds too old	Increase temperature to 24-25°C, use fresh seeds
Mold on cubes	Too wet, poor air circulation	Reduce watering, increase airflow
Seeds rot before sprouting	Overwatering, dirty equipment	Use sterile medium, clean trays

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Part 2: Seedling Stage (Days 6-12)

Once the seed sprouts and the first true leaves appear, your plant is in the seedling stage.

What’s Happening

• First cotyledons (seed leaves) provide initial energy
• True leaves (first real leaves) begin photosynthesis
• Root system develops rapidly
• Plant becomes less dependent on seed reserves

Optimal Conditions for Seedlings

Parameter	Recommendation	Notes
Temperature	20-22°C (68-72°F)	Slightly cooler than germination
Humidity	65-75%	Lower than germination to prevent disease
Light PPFD	100-200 µmol/m²/s	Start low, increase gradually
Photoperiod	16-18 hours	Long days promote growth
EC	0.8-1.2 mS/cm	Low nutrient concentration
pH	5.5-6.2	Same as germination

Daily Seedling Care

What to check each day:

Task	Frequency	What to Look For
Check moisture	Daily	Medium should be moist, not wet
Measure EC/pH	Daily	Keep EC below 1.2 for seedlings
Inspect roots	Every 2 days	White roots = healthy; brown = problem
Rotate trays	Daily	Prevents leaning toward light
Remove humidity dome	Day 5-7	Gradually expose to lower humidity

Signs of Healthy vs. Unhealthy Seedlings

Healthy Signs	Warning Signs
Bright green color	Yellow leaves (nutrient deficiency or overwatering)
Sturdy, upright stem	Leggy, stretching stem (too little light)
White, fuzzy roots	Brown, slimy roots (root rot)
Uniform growth	Uneven size (uneven light or water)

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Part 3: Transplanting (Day 13)

Transplanting is moving seedlings from the germination tray to your main vertical growing system.

When to Transplant

Your seedlings are ready when:

• 2-3 true leaves have developed (not counting cotyledons)
• Roots are visible at the bottom of the rockwool cube
• Seedling height is 3-5 cm (1-2 inches)
• Typically around day 12-14

Pre-Transplant Preparation

One day before transplanting:

1. Prepare your main growing system (NFT channels, towers, or deep water culture)
2. Run the system with plain water to test flow
3. Adjust pH to 5.5-6.0
4. Set EC to 1.2-1.5 mS/cm

On transplanting day:

1. Gently remove seedlings from tray
2. Inspect roots — white and healthy only
3. Discard any weak or diseased seedlings

Step-by-Step Transplanting Process

Step 1: Place seedling into growing system

• Insert rockwool cube into net pot or grow channel hole
• Ensure cube sits firmly but not crushed
• Roots should touch or be near the water/nutrient film

Step 2: Check water flow

• For NFT: water should flow at 1-2 cm depth
• Roots should be in contact with nutrient solution
• Adjust flow rate if needed

Step 3: Set initial conditions

Parameter	Setting
PPFD	150-200 µmol/m²/s
Photoperiod	16-18 hours
EC	1.2-1.5 mS/cm
pH	5.5-6.2
Temperature	20-22°C

Step 4: Monitor for transplant shock

• Some wilting is normal for 24-48 hours
• If longer, check water flow and root contact
• Maintain high humidity (70-80%) for first 2 days

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Part 4: Vegetative / Maturation Stage (Days 14-25+)

This is the growth phase where plants build biomass — leaves, stems, and roots.

What’s Happening

• Rapid leaf expansion
• Stem thickening
• Root system fills the growing channel
• Plant prepares for harvest

Optimal Conditions for Maturation

Parameter	Leafy Greens	Herbs	Fruiting Crops
PPFD	200-350	200-300	350-500
Photoperiod	16-18 hours	16 hours	14-16 hours
EC	1.5-2.0	1.2-1.8	1.8-2.5
pH	5.8-6.2	5.5-6.0	5.8-6.5
Temperature	20-22°C	20-24°C	22-26°C
Humidity	60-70%	55-65%	55-70%

Daily Management During Maturation

Every day:

Task	Action
Check EC/pH	Adjust as needed
Inspect water level	Top up if low
Check for pests	Look under leaves
Observe plant color	Yellow = problem

Every 3-5 days:

Task	Action
Prune dead leaves	Remove yellow or dead lower leaves
Check roots	White = healthy; brown = flush system
Adjust light height	Maintain 30-50 cm above canopy

Every 7-10 days:

Task	Action
Change nutrient solution	Completely replace reservoir
Clean system	Remove algae or debris
Calibrate sensors	EC and pH meters

Growth Milestones by Crop Type

Leafy Greens (Lettuce, Kale, Spinach)

Day	Milestone
5	Germination complete
10	First true leaves appear
15	Transplant
20	Rapid leaf expansion
25-30	Harvest ready

Herbs (Basil, Cilantro, Mint)

Day	Milestone
5-7	Germination
12	First true leaves
15-18	Transplant
22	First pruning (for bushier growth)
30-35	First harvest

Fruiting Crops (Tomatoes, Peppers)

Day	Milestone
7-10	Germination
15-18	Transplant
25-30	Vegetative growth
40-50	Flowering
70-90	First fruit harvest

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Part 5: Harvesting

Knowing exactly when to harvest maximizes both yield and quality.

Signs Your Crop is Ready

Crop Type	Visual Signs	Days to Harvest
Lettuce	10-15 cm tall, 5-8 leaves	25-30
Kale	15-20 cm tall, 6-10 leaves	28-35
Basil	10-15 cm tall, harvest before flowering	30-35
Pak choi	12-18 cm tall	25-30
Spinach	8-12 cm tall	25-35

Harvest Methods

Whole Plant Harvest (Most Common)

• Cut at the base just above the growing medium
• Remove entire plant at once
• Best for lettuce, pak choi, single-harvest greens

Cut-and-Come-Again

• Harvest outer leaves only
• Leave the growing point intact
• Allows 2-3 harvests from same plant
• Best for kale, chard, some herbs

Post-Harvest Handling

Step	Action
1	Rinse roots gently to remove nutrient residue
2	Shake off excess water (do not soak)
3	Pat dry or use salad spinner
4	Store in perforated bags or clamshells
5	Refrigerate at 4°C (40°F) immediately
6	Mist lightly if storing longer than 3 days

Expected Yield per Square Meter

Crop	Yield per m² per harvest	Harvests per year
Lettuce	3-5 kg	12-15
Kale	2-4 kg	8-10
Basil	2-3 kg	10-12
Pak choi	4-6 kg	10-12

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Part 6: Complete Growth Cycle Summary Table

Stage	Days	PPFD	EC	pH	Temp	Humidity
Germination	1-5	5-10	0.5-0.8	5.5-6.0	22-25°C	80-95%
Seedling	6-12	100-200	0.8-1.2	5.5-6.2	20-22°C	65-75%
Transplant	Day 13	150-200	1.2-1.5	5.5-6.2	20-22°C	70-80%
Maturation	14-25+	200-400	1.5-2.0	5.8-6.2	20-24°C	60-70%

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Common Problems Across All Stages

Problem	Stage	Cause	Solution
Leggy seedlings	Seedling	Too little light	Increase PPFD to 150-200
Root rot	Any	Overwatering, poor oxygen	Lower water level, add air stone
Yellow lower leaves	Maturation	Nitrogen deficiency	Increase EC to 1.8-2.0
Slow growth	Any	Temperature too low	Raise to 22-25°C
Algae on medium	Germination	Light hitting wet surface	Cover cubes with light-blocking material
Wilting after transplant	Transplant	Transplant shock	Increase humidity to 80% for 2 days

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Summary: Your Growth Cycle Checklist

Before you start:

• Clean and sterilize all equipment
• Calibrate EC and pH meters
• Prepare nutrient solution
• Test system flow

Germination (Days 1-5):

• Maintain 22-25°C temperature
• Keep humidity at 80-95%
• Check moisture daily

Seedling (Days 6-12):

• Gradually increase light to 200 PPFD
• Lower humidity to 65-75%
• Monitor root color

Transplant (Day 13):

• Prepare main system
• Handle seedlings gently
• Watch for transplant shock

Maturation (Days 14-25+):

• Increase EC to 1.5-2.0
• Check EC/pH daily
• Change nutrient solution weekly
• Harvest at peak maturity

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Next Steps

Ready to master your growth cycle?

• Read our Nutrient Management Guide for detailed EC/pH strategies
• Check our PPFD/DLI Complete Guide for light optimization
• Contact us for crop-specific growth protocols

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