I agree with Keriann. Yes, you should really let them dry out. Matter of fact, once my seedlings are as big as yours, I let them dry out pretty much all the way before I water again. You can tell they need watered when you pick up the flat and it feels light as a feather. Then after you water, it's much heavier. Your method of bottom watering is quite unique, I must say. I think that most folks bottom water the way I do, which is to say setting the cells or cups into a tray of water and letting the plant absorb as much as it wants until you see moisture on the surface of the soil (usually takes anywhere from 5-20 min). Now, I can't say for sure what positive or negative effects your method of watering might have, except that it sure sounds like a pain in the hiney to me, and I somehow doubt that the soil is getting properly saturated. You want to simulate mother nature; a soaking rain. Then you want to let the soil dry out. That's how it is in nature. Roots need water yes, because the plant needs water, but then they need to dry out and get oxygen. Damp soil all the time = no oxygen to the roots. Now, I can't say for certain what part of your program is causing your issues, but I would start bottom watering them as described by letting them absorb water sitting in a tray. I think you will find that using this method, you should only have to water every 3-4 days, or less. I would lay off the ferts for a while, and then make sure only to fertilize when the soil is already damp, or you will burn the roots. I just mix the fert with water, then pour into a tray and bottom water as usual. Give this a shot, see if that doesn't help.

Anthracnose? If so, I think treatment is the same for blackspot.

Shaq, Someone gave me cuttings of dwarf plumeria and the stuff under the leaves look like what's on your plant: In a plumeria forum on another website I asked whether it was diseased. This is the response I got from an expert: "It's not super healthy. I'd start by clipping (not tearing) off the leaves, then maybe spray it with some insecticide and see how the new leaves come in." Maybe someone here who also raises plumerias could pipe in and tell what it is and how to get rid of it. -Kadie

Any damage that is showing on your plants is mechanical - that means it came to be from shipping and other transport, handling or jostling. It is not the result of diseases or insects nor does it look like any watering issues. In reality, these plants look pretty darn good considering most big box stores do not take the slightest bit of care with their plants (hence the evidence of damage you are seeing). As to fertilizing, you need to identify your plants and then do a bit of research, as not all plants benefit from similar fertilization methods nor do they require it at the same time. Cacti and succulents have different needs than do tropical foliage plants and flowering houseplants (orchids, African violets, flowering gift plants) have yet another set of needs. In general, an all purpose liquid fertilizer used at 1/2 to 1/3 strength with every other watering is appropriate for most tropicals during their primary growing season (March through October) but you can get by with quite a bit less. I'd suggest you post this on the House Plants forum both to get accurate ID's on your plants and their advice as to when, how much and with what to best fertilize what you have.