I have recently planted an upright herb garden. While setting up a watering system, two weeks later my oregano has this fungus or mould which is making its way to the thyme.

What is it and how do I treat it?

what is it?


I added the first image via the stack exchange iPhone app. I didn't expect it to be low quality. So here is another high res one.

enter image description here

Here is a side on shot of the upright herb garden if that will help. (the oregano is in the second pot from the bottom. enter image description here

  • The images provides a sufficient idea, but you probably should add another one with more detail and higher resolution.
    – dakab
    Jul 23, 2016 at 8:07
  • What do you mean by 'upright' herb garden? And are the herbs in a container or in the ground? If contained, is there good drainage for excess water to escape?
    – Bamboo
    Jul 23, 2016 at 11:13
  • @Bamboo I have attached a side shot of the setup, the water is caught in trays at the bottom of each pot and drain out the front center into the pot below if they over fill. Jul 25, 2016 at 3:37

2 Answers 2


Change the environment to create one much more suitable for growing these plants. It's a good thing you told me where the Oregano was in the third picture, because it's next to impossible to tell. I'm afraid this particular planting arrangement isn't going to work because all the plants are crammed much too close together, with no opportunity for air flow between them, and with growth flopping over on top of other plants. Added to that, you seem to be saying there are trays beneath the pots which trap water, and only when the trays are full does the water drain away, meaning there is always some water in the trays.

Most herbs like open, sunny situations with free draining soil; obviously, in pots, they need regular watering, but will not tolerate being left sitting in water, no matter how small an amount, over time. I'm sorry to say that the only time I've seen this sort of fungal problem has been when plants are cramped up together and there's too much water around, either from excessive rain over days or as in this case, cramped conditions causing poor or no airflow and insufficient drainage.

The only way to save your plant/s is to separate them, and in the case of oregano, potting up into something wider - this particular plant is a strong grower and wants to spread quite quickly, but all of your herbs really have insufficient room for growth. Left as they are, you will probably find the fungal problem spreads to most of them.

If you want to save the oregano and thyme (the ones already showing signs of fungal infection at soil level) take them out of their pots, strip away the infected parts, including at root level if its there too, repot into something bigger (with a drainage hole or three) and stand them, separately, in sun or partial sun if you're somewhere very hot, where they can have free airflow around them, keep them watered but not standing in water.

If you have room in the garden, oregano makes a good edging plant, but will need digging up and splitting yearly.


The fungus looks like Botytris cinera for what it's worth. There's a variety of control products out there. Azoxystrobin is what the big boys use. Copper is the organic choice. Also, the cultural methods that bamboo described are important (like, 90% of the issue/battle).

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