I had a few small trays of seedlings from my azalea crosses of 2011 that I decided need to be transplanted out before they become two crowded. Very beautiful, lush seedlings. For example, R. prinophyllum X R. occidentale
(see photo). Since there was only 5-10 plants from each cross and I don't have a proper trial field for the seedlings I made individual, round beds for each batch in a half-shady "meadow" on the property. The meadow has rather thing, hard mixed moraine-clay
soil, so (after killing weeds with glyphosate) I mix a wheelbarrow full of well-rotted horse manure and a bag of cheap, commercial compost, make a round bed with a depth of 15-20 cm and plant the seedlings in that. Finally, I cover the surface with a thin
layer of home-made mulch (wood chips) and water well. These mini beds turned out to retain moisture very well even during our exceptionally hot July month and the azalea seedlings look great now in mid-August. I have transplanted about 7 batches of rhododenron
seedlings similarly. I hope these conditions will allow at least most of the plants to reach flowering size before they get too crowded.