I’ve taken over an old greenhouse in which plants and fruit had been left to rot. I cleaned it inside and out with milton and washing up liquid and it looked great. Unfortunately though when I left a couple of plants in it some of them have developed a kind of fungus, (black spots which are spreading rapidly) I read somewhere that I can get a fumigating candle but can’t find one. Is this a good idea and if so, where could I find one?
The damage may have been just the change of scene. Ventilate the house to allow natural airing to take place. Most greenhouses are never fumigated or sterilized and plants do fine for decades.