There is a general rule to not sow any seeds 6 weeks either side of Christmas, as there is just not much energy from the sun available in terms of both light and heat and seeds and seedlings can struggle to get going.
There are some seeds that can be sown in January but there are caveats to this – see below:
Unheated in module trays or pots under cover from mid-Jan:
- Asian salads
- Lettuce
- Sweet peas – beware of mice, they adore sweet pea seeds
- Poppies – prefer to be direct-sown but will do fine from modules too
With heat for germination and then unheated undercover:
With continuous heat and light – ADVANCED! Plants will get very weak and leggy without the right amount of heat and light:
Direct:
- Poppies – some people sprinkle poppy seeds onto fallen snow in the winter
