by Terry Mitchell, APS and NAPS
(This article was written in response to a question posed in a discussion group.)
It is very difficult to give a satisfactory answer to the problems you are having without seeing and inspecting the plants and the situation you are growing them in. Although you gave a lot of information about your problem there are some important points you didn’t mention which could help to give a better idea of what is going wrong.
You say you grew your Auriculas in the first 24 feet inside the door of your greenhouse. You also say the door is kept open while you are working in there at least 8 hours a day. Does the greenhouse have side vents and roof vents? Are these kept open in all but severe weather? Just having a door open would not give anything like enough ventilation, and I believe this is possibly causing the botrytis you are getting.
Heating is not necessary for Auriculas. They must, however, have a good movement of fresh air around the plants, even if it is cold or freezing air.
The yellowing of the leaves is normal through late autumn and the winter. If you are removing these leaves as soon as they start to yellow you will more than likely be damaging the carrot (meaning the main stem of the auricula) and the leaf joint on the carrot of the leaf above. This will cause that leaf to start yellowing; it is a vicious circle.
You say you finish up with long carrots and very little foliage. The leaves should only be removed through the winter if they have dried up and gone papery in texture, or if they go thin and wet and are then a threat to the plant from botrytis.
When new growth gets under way in early spring, the plants with long carrots can be carefully eased out of the pot, hopefully keeping the root ball intact. Some compost should be gently teased from the bottom of the root ball and the plant carefully lowered back into the same pot. It will now sit lower in the pot and fresh compost should be used to fill the pot back up. This will cover the long unsightly carrot and cause new roots to form from the carrot at a higher level. It is normal practice for the lower roots and carrot to die to some extent in any case.
Overwatering kills far more Auriculas through the winter than underwatering. The compost should be kept just damp, and any watering should be carried out on the best weather days possible for the winter. Watering is best done early in the day to give time for any careless splashes of water on foliage, etc. to dry before nightfall (another source of botrytis).
The compost you use for Auriculas is crucial and has to be very open. A good loam based or John Innes type compost with plenty of sharp grit and sharp sand added is called for. This stimulates good strong healthy root growth. If you tap a plant out of its pot you should see strong, healthy white roots running right through the root ball. If all the roots are brown and soggy and rotting it is a good sign that you are overwatering or the compost is not open enough. Peat based composts are not suitable for Auriculas as they retain too much moisture.
You say the flowers never last more than 2 to 4 days before collapsing. Unless you have vine weevils, or some other pests in the pot damaging or eating roots, it again sounds to me like overwatering, the wrong type of compost, or a combination of both.
The problem with the double vulgaris seems to bear out the fact that you are not getting good air movement round your plants. The mummified buds can occur if you are getting water on them or the plant, or if they are growing in damp stagnant air. This also leads to the botrytis that you mention follows the mummified bud stage.
I hope this helps you to eliminate the problems you are having. As I said, it is difficult to make a satisfactory answer without seeing the problem first hand. Please let us know how things go.