Got mini plugs on friday. Some just disappeared. I caught our dog gently pulling some out! He sees me dig & joins in. When I cut or saw branches he starts on his own projects...This week I put him on a long lead in the garden shade...
When I purchase the Mini plugs bramhallbill, I do those around March / April here in UK, I then pot them up soon as, into individual small pots, place those on a tray that has NO holes, then water from the bottom till they look like the size that will be able to go outside and support themselves, TOO small and they either flop and die due to not being large enough. plants that have been started indoors (normally plug plants are a prime example) they need to be kept inside and gradually hardened off, to do that, pot them up as mentioned and place pots into trays.
Each day place them outside to harden them off and get used to their new environment, keep the watering going IF needed, bring the plants back inside each night and do this for a week or so, them when your happy they are growing well, that's when to plant into beds, baskets or tubs outside to grow on.
Not sure when you planted yours outside IF the soil was too warm and the little plants just gave up, or something ate them. Slugs and snails amongst other creepy crawlies are ready to pounce as soon as we give them the new tender growth that ALL small and tiny plants have when new. Maybe check out that IF you found any of the slime trails on the soil
IF possible can you tell us if you planted into the garden soil in a bed, or into pots, or basket / containers, did you amend the soil like add compost, add any plant feed, watering, did you water them. these answers would help and also what type of plants are you talking about, Plug plants cover anything from fuchsia , Aubrieta, Nicotina, there are too many to mention BUT all require the same treatment from buying them at mini plug plants to being able to sustain the new environment you give them.
Hope this helps a little and IF you can get back to us, maybe we can help you sort things out for next years summer garden, I fear it's too late for this year now as Bedding plants have a very short season to show themselves off to their full potential.
Best of luck. WeeNel.