Just a quick point…the above tray holds four smaller trays…each of 15 pots. 60 pots in all….as a rule of thumb this would fill up a productive flower bed of one metre across and 20 metres long…you could squeeze a few more in but too many more and the plants would become over crowded….and this would make them miserable…and they would punish you by producing less flowers….and this would make you miserable.
NB I have sown these up a little early….even by Cornwall standards…best not follow my lead…..April is better.
Kind regards
Benjamin