- 01
Choose the right growing medium
Go for a light, well-aerated medium that holds moisture without staying soaked, with a pH between 6.2 and 6.8. Fill a 5–10 litre pot and leave it at least 24 h in the germination room before sowing, so the medium reaches room temperature.
- 02
Prepare the germination room
Temperature is one of the most important factors. Aim for 25–30 °C air and 65–80 % relative humidity. Stable conditions give faster, more even germination.
- 03
Prepare the seed
Keep seeds in the fridge until sowing to preserve their viability. On the day, take the seed out and soak it for 12 h in non-chlorinated water above 20 °C to rehydrate it — never beyond 24 h, so the seed isn’t starved of oxygen.
- 04
Sow it correctly
Plant the seed about 3 cm deep, tip pointing up and tilted at 45°. This position eases the seedling’s emergence and limits the risk of the cotyledons getting stuck in the seed coat.
- 05
The first watering
Add about 20 cL of water above 20 °C: tempered water avoids thermal shock. The medium should be moist, but never soaked.
- 06
Wait for emergence
Over the next 4–6 days, watch the medium’s moisture, check temperature and humidity daily, and avoid any over-watering. The goal: a stable environment until the seedling emerges.
- 07
As soon as the seedling appears
Place the seedling under a grow light immediately: 16–18 h of light, 6–8 h of night. I like to sync the lighting with the sun (e.g. 5 a.m. → 11 p.m.) to make the move outdoors more natural.
- 08
Hardening off
Two weeks after germination, the young plants can move to the greenhouse. A few days before final transplanting, gradually accustom them to outdoor conditions to limit stress. Try lowering the grow box’s temperature so the plants aren’t too disturbed.
- 09
Pick the right date
Under glass: sow around 15 April, plant early May. Outdoors: sow early May (indoors), plant between 15 and 20 May (once all risk of frost has passed).
The extra tips that make the difference
- A soil thermometer: a medium temperature of 26–28 °C encourages fast emergence.
- Don’t compact the medium after sowing — young roots love an airy substrate.
- As soon as the surface of the medium starts to dry, mist it rather than re-wetting the whole pot.
- From the cotyledon stage, increase ventilation a little: less damping-off, sturdier plants.
- If the seed coat stays stuck on the cotyledons, moisten it before removing. Never force a dry coat.