Meanwhile here's a whistle stop tour of this year's seedlings and what we've started them in:
Loo roll/kitchen roll inners - great as substitute root trainers but can dry out quickly so you need to make sure to keep watering. We've also found that they are better for things that don't need to be left in the tubes too long before planting out as they can disintegrate if left for too long. We pop shredded paper or a ball of newspaper in the bottom before filling with peat-free compost and then group them in 5/6 tube sets with a large elastic band round (think royal mail cast-offs). We then stand them in mushroom tubs or broken plant pots to help them stand up.
Paper cups - we don't usually have any drinks in these but a recent bout of hospital visits meant we'd acquired one so thought we'd try re-using it when we got home. The wooden stirrer even came in handy as a label.
Grape punnets - we have used these as mini propagator lids for a few years but after seeing someone on twitter use them as a planter we've sown some of our peas and beans in them and the extra depth seems to work really well. Most come complete with drainage holes so are ideal as deep seed trays. This batch of pea-shoots are also standing in an old mushroom tub which serves as drip catcher.
And then there's the obvious - it always alarms me when I read "living without plastic" articles and social media posts that advocate throwing out what you have and replacing it with terracotta/ceramic/paper etc. - NO! Please, please, please use any pots, modules and seed trays that you have.
Most of these have been around for years and still have plenty of years life left in them and the best thing we can do for the planet is to keep the plastic we have in use for as long as possible - once it's binned it's just hazard to our soils, waterways and wildlife and that's the last thing any of us need to be causing.