And in today's Cheap But Useful section we have... the used plastic tub.
Which ever low fat spread you buy these days, nobody uses real butter except me I think, clean out the tub in hot water. Fold a paper towel to fit the bottom, place in seeds, rip a piece of paper towel to fit over the seeds, dribble a quarter strength mix of whatever fert your using over the seeds/towels until wet all round. Close lid of tub, place in dark warm place, leave alone for two days, done.

peace