My First Autoflower Growing Indoor 🌸
Finally! I've decided to document my very first autoflower growing experience, starting from scratch with a 60×50×104 cm growbox. It's small, I know, but perfect for learning the ropes and figuring out how everything works.
Reality Check: My First Tests
During preliminary tests, I discovered something interesting and slightly concerning: starting from 26°C room temperature with the AC running, my growbox hits 28-29°C in about 2.5-3 hours. The maximum peak? A whopping 32°C with lights on and the box fully closed!
For now, I've put a damp towel inside - sounds like a DIY hack, but it actually works to stabilize temperatures a bit and reduce those thermal swings.
The Economics of It All
Smart plugs let me monitor power consumption in real-time - currently running about €0.11/kWh. In a few weeks, I'll have to turn off the AC (my wallet will thank me!), so the first weeks will be characterized by high temperatures around 30-31°C. Fortunately, September and October should bring cooler conditions.
My Germination Strategy
During germination, I'll keep the lamp 60 cm from the seedlings - that's the maximum height I can manage in this box, but it should minimize light and heat stress on those emerging roots. Later, when the plants are stronger, I'll transfer them to the larger 60×60×180 cm growbox.
Oh, almost forgot! A 350 ml/h ultrasonic humidifier is on its way, which should give me much more precise humidity control.
My Current Setup
The Growbox: 60×50×104 cm - perfect for two autoflowers in 6.5L pots using LST (Low Stress Training).
Lighting: Spider Farmer SF-1000D suspended via pulley system near the ceiling, with about 4-5 cm clearance for heat dissipation.
Ventilation: 130 m³/h extractor (4" diameter) that expels hot, humid air directly out the window - genius for preventing the room from becoming an oven! Plus a USB clip fan for internal air circulation.
Climate: Ambient temperature stable around 26°C; inside the box 27-28°C without lights, jumping to 32°C when they're on.
Substrate: BioBizz Light Mix combined with leftover perlite I had - exact quantity will depend on what's available, aiming for the right balance between aerated structure and water retention capacity.
Nutrition: BioBizz Fish-Mix for vegetative growth, plus Grow and Bloom. pH maintained between 6.2-6.5. No CalMag for now.
Monitoring: Two digital hygrometers connected to an app - one inside the growbox, one in the room. So I can check everything from my phone!
Humidification: Two traditional humidifiers, plus the ultrasonic one coming for finer control.
My Observations and The Plan
The ventilation system works well - it manages to prevent heat and humidity from building up both in the box and the room. That's a win!
The germination strategy is simple: lamp at 60 cm and hope for the best. The first weeks will be challenging with those high temperatures (30-31°C) when I turn off the AC, but then autumn should help me out.
The plan is to grow the seedlings in the small box, then transfer them to the big one for flowering. Meanwhile, I'm monitoring everything: temperature, humidity, power consumption. The goal is to optimize the on/off cycles.
Final Thoughts
This first cycle is more of a technical experiment - I want to understand how to manage climate and lighting, stabilize temperature and humidity according to what the plants will ask for at each stage.
The transfer to the larger box and winter approaching should improve conditions for optimal growth and flowering.
I'll update this diary with all the quantitative data: yields, organoleptic characteristics, setup modifications. It'll be interesting to see how this first adventure turns out!
Stay tuned for the next update!
Ps: there is also a hole where the air enters passively, only it is hidden by the fan ❤️ 😅
==UPDATE==
BY INSERTING AN ULTRASONIC HUMIDIFIER I ACHIEVED THESE RESULTS, WHICH IS PERFECT
🌡️ Temperature: 23.3°C / 73.9°F
💧 Dew Point: 16.0°C / 60.8°F
💧 Relative Humidity: 63.6%
☁️ Absolute Humidity: 13.3 g/m³
💨 Vapor Pressure: 18.2 mbar
🌱 VPD (Water Stress): 0.66 kPa
💨 Air Density: 0.012 kg/m³
✅ Comfort Index: 100/100
🌿 Heat Stress: ✅ Optimal
🔋 Battery: 100%
⏰ Last update: 08/17/2025 12:49:35
I created a Python script that, starting with just 2–3 parameters measured by my Govee H5075 hygrometer, uses real scientific formulas to calculate all the other environmental values. This way, I can monitor my grow box much more effectively! I knew AI and programming skills would come in handy for this too lol ❤️🤣
==UPDATE 22 AUGUST==
Photoperiod:
➜ Emergence (day 0): 1 day without artificial light.
➜ Days 1–2: indirect natural light from the window.
➜ 17 August: first day under the lamp → 8 hours.
➜ 18 August: increased to 15 hours.
➜ From 19 August: stabilized at 16 hours of light per day, likely to remain this way due to practical reasons.
Lamp distance:
➜ From 21 August: distance reduced from 60 cm to 50 cm → noticeable and more consistent growth.
Plant status:
➜ Healthy plant with gradual growth.
➜ LST (Low Stress Training) will be applied in the next days to control height and shape.
Watering & nutrients:
➜ Method: Med-Man.
➜ Water at 130 ppm, pH between 5.8–6.0.
➜ From 22 August: start of light foliar spraying (10 minutes before lights on) with pH 6.0, using a mixture of 3 parts water : 1 part Grow fertilizer.
➜ Purpose: slightly stimulate the plant during the early growth stage.
Internal climate:
➜ Average temperature: 26–27 °C, with peaks up to 28–29 °C when the air conditioner is off.
➜ Humidity: kept stable using humidifier + damp cloth inside the box, which lowers temperature slightly and stabilizes the environment.
Planned improvements:
➜ Purchase of:
➜ Dehumidifier for better humidity control.
➜ Wi-Fi hygrometer for more precise monitoring.
➜ Adjustable extractor fan, to better manage airflow and reduce nighttime noise.