Hi Terry, and welcome to ATP. I hope you enjoy gardening for decades to come.
What you described does sound more like bugs than fungus. Probably the LEAST toxic of insecticides is "insecticidal soap" like Safer's.
I don't know ways of dealing with bugs, unless they happen to be there
because they are dining on fungus or dining on smaller bugs that are dining on fungus.
If the problem WERE fungus:
Air movement will help fight fungus.
Drier air inside the greenhouse will help fight fungus (vent it more often).
You can water with 0.2% hydrogen peroxide instead of tap water
(one ounce of drugstore peroxide per quart or
1/2 cup drugstore peroxide per gallon).
You can sprinkle cinnamon on the soil surface (cheapest at the Dollar Store)
You can make chamomile tea and water with that.
You can make the soil surface drier by:
- - bottom-watering instead of watering from the top (*)
- - covering the soil surface with something that drains and dries out fast, like coarse bark chunks or coarse grit
- - next time you re-pot something, use a potting mix that drains faster and has open air spaces to help the surface (and the rest of the soil) dry out
If fungus is being stimulated and fed by a very organic potting mix, you might use a mix that is less organic, like less or no compost.
Often containers need something that drains faster than, and resists compaction better than, soil-soil. Many people use a soilless mix for plants in containers.
That's mostly a suggestion for the next time you re-pot or start a new plant, but you MIGHT be able to scrape some soil from the surface, and replace it with a less-organic and less-water-retaining mix. However, containers usually do better if the potting mix is uniform from top to bottom instead of having layers with very different drainage. If the mix is uniform, capillary action makes it all one layer and water tends to drain DOWN from both gravity and capillary action.
If there is a mis-matched layer, the capillary connection may not span the interface, so that water pools and "perches" in the higher layer. If that keeps you soil surface too wet, it would encourage fungus and might encourage roots to rot.
Have you gotten into seed starting? It might be more challenging than growing on plants that someone else started, but you have the satisfaction of "creating life" from seeds. I think that starting seeds indoors teaches how to make well-draining soilless mixes because tiny seedlings are very vulnerable to damping-off fungus.
(*)
I was never able to bottom-water my seedling trays without clogging the bathtub's drain, until I stumbled on the idea of sitting the trays on top of cotton flannel in a 1020 tray. Then I could just keep the flannel damp, avoid standing water completely, and trust to seedling roots and soilless mix to wick up enough water to keep the plants happy but not enough to exclude air and drown the roots.
http://garden.org/ideas/view/R...
