All newly planted plants require regular watering until they are established, plugs more so. If by planting out, you mean into the ground now, these plants are frost sensitive, with O. jucundum being the hardiest. Even that is best planted in spring though, so best pot up the plugs and keep somewhere frost free over winter, unless you live somewhere warm and not in the UK.

Be careful with watering, particularly with the rubbish composts that are on sale at the moment! ( Many of these tend to hold on to water/moisture!)

These plants grow on mountain sides in their indigenous habitats where the soil is free draining.

So you may have to add some horticultural grit to your compost to ensure the compost is indeed 'free draining'