Dracula black and brown spots?

Hi Maria, I've been thinking about this since I saw it this morning. Possibly a bacterial issue? It appears as if the main problem is only on the older leaves so my guess may be a part of the aging and not necessarily a major problem. It doesn't look like virus (which you would see in the new leaves). I do see that you have quite a few trimmed leaf tips on older leaves which would make me think that not everything is ideal. Possibly the water quality? Or maybe the medium is getting dry at times causing a concentration of salts. I didn't quite understand what you were saying about the fertilizer. Did you mean you don't often fertilize them? It may be that the picture is a bit over-exposed, but the leaves are a much lighter color than what I think of as a happy dracula and it appears a bit stressed which could also make it more prone to the spotting.

 

As you are trimming those leaves, be sure to use something sterile (single use razor blades or clippers that have been flamed with a torch) so that you don't spread virus. Did you repot it when you got it? What is it potted in? Can you see roots running around the pot at all? If the media is staying too wet, there won't be enough air space for them to grow well. It is worth taking the plant out of the pot and checking the roots.

I run fans 24 hours a day, every day. Air movement is very important, especially at night when the temperature drops and you may get more condensation. Most of the time the leaves should be dry by night. That will help avoid bacterial problems.

Rain water is good since it is relatively pure. The problem is that since it is pure there are NO nutrients for your plants and you are probably starving them. In nature, there is a constant, dilute supply of nutrients available to the plants. I fertilize at 1/4 strength (approx 1/4 tsp per gallon) every time I water. Before I started doing that many years ago, I would fertilize every 2nd or 3rd time I watered. In the winter, I would decrease the frequency or concentration. For my draculas that are growing in low light, I don't get as many blooms as for those that are receiving more light.

The amount of fertilizer needs to be balanced by the temperatures and amount of light the plant gets. Up to a point, the more light it gets, the more fertilizer it can use. A balance between them should give you darker healthier leaves than you have. You might not want to fertilize as often as I do, but your plants need more than they are getting.

I didn't ask if they are in a greenhouse, under lights or on a windowsill.

 

Maria, did you notice that the leaves in this picture are darker. That is a good color for them. If you increase the fertilizer so that you get a green more like this you will be doing well. I doubt that your problem is too much light.

How often do you water now? I think that most orchids like something of a wet/dry cycle so the roots are not always soaking wet. It sounds as if yours are very wet all of the time. You can change how wet the roots stay by varying the media and/or the pot. A plastic pot is going to keep things a lot wetter than a net pot or a porous ceramic pot. If you want your roots to be less wet and keep this medium, change the type of container or use a plastic pot with LOTS of holes in the sides and bottom. Many people (me include) have success with good quality sphagnum moss in a net pot. It has to be loosely packed so there is lots of air around the roots. Just packed in enough so the plant doesn't wobble. Most any medium will work as long as you adjust the light, air movement, water, fertilizer. Trial and error is needed to get the combination right. Everything works in balance and what might work in one situation may not work in another.

If your humidity is always high, you might try growing them mounted where the roots can dry a bit between waterings.

You can foliar feed if you want, but if your humidity is so high that you aren't watering regularly, I think you may have it too high. I don't grow in a case, but even those I know who do, water regularly.

Marni