Seeds, a DIY germination chamber, heat and light!
Using Airtable, we are able to check how many seeds were planted last year compared to this year. It is remarkable that we have planted 3000 seeds in 2026 so far, and 3100 during the same time in 2025. I just imagined that we were behind the curve.
The DIY germination chamber (GC) is a game changer and there are various options used by market gardeners; both Pillars of Hercules and East Neuk Market Garden use a tall fridge with a slow cooker in the bottom shelf, controlled by a reptile thermostat that keeps the inside of the fridge at a constant temperature. Fridges and freezers are just well insulated cupboards, and we’re using them to keep the heat in.
The Sanctuary Garden version is an undercounter fridge with an ST1000 controller and a 60w heating element and it’s been set to 22.5oC. Obviously there is no light inside the fridge so it’s really important to put the seedlings under light as soon as most of them have emerged or you end up with very, very leggy seedlings. We’ve had a few failures with overly long stemmed seedlings.
The germination rate using this germination chamber (GC) is remarkable. Using heating cables beneath sand, I remember being disappointed by how few chilli and aubergines germinated last year. In the GC, the germination rate is about 75% which is great for any seed in ideal conditions. This is particularly important when you buy seed packets with a stingy 5 or 6 seeds enclosed. I’ve noticed seeds from Europe are very generous compared to seeds from the UK, especially from the big names.
This year, we have the significant advantage of a grow-tent, grow-lights and heat. helping our seedlings. The tomatoes now have their first real leaves and have been pricked out into bigger pots.
Lights are ‘complicated’; or at least the marketing and internet forums make it look complicated quoting UV, infrared, red, blue and daylight. At the cheap end, the LED versions are completely useless unless you are growing one seedling.
These are my empirical findings: use a warm white LED bulb, 150w in old money, and have it on a timer so it’s on for 18 hours and off for 6. ‘Daylight’ LED bulbs are great for established plants and ‘blue’ light will make seedlings leggy. In a local general store 4x 150w bulbs and 4 pendants cost £30 and 2 bulbs are hung per shelf 89cmx 50cm (IVAR from IKEA) filled with seedlings. We could probably use just one blub. By the equinox where the days and nights are equal – not the meteorological spring (seriously who made that up) you can put the seedlings outside as there is enough light for them to not become leggy. (with heat and frost protection.)
Keeping seeds in a dry, cool and dark place is critical to their viability. A photo organiser (6″x4″) is a perfect option.
