Hi all

So 9 days ago I put something like 45 seeds into 3 containers for germination.

I have previously managed to get cactus seeds to germinate before fungus set in, but this may he been beginners luck!

This time I sowed ~15x bridgessii / ~15x pachanoi / ~15x peruvianus into 3 separate plastic food containers with oven-cooked cactus soil/perlite and centimetre a sifted layer of oven-cooked cactus soil.

At 9 days a few seeds are showing small white sprouts and there are also a couple of ~2mm seedlings, so far so good apart from that 2 containers are showing small amounts of white fungus.

I think if it starts to grow too fast I will remove the seeds and then put them into newly sterilised earth/containers.

So I have a couple of questions–

What are good anti fungus tactics? I know there are specialised ones out there but I also hear that they aren’t too good for seedling growth and may be a hindrance at this early stage in their lives. I also read that a spray of white vinegar for 2 days may kill the fungus. I like this idea as at least it is a food safe option. Other options I have heard are mild bleach solution. Any advice?

Also to slow the onset of fungus growth in the first place would it be helpful to germinate with the same setup I specified earlier, but with a small layer of sand on the top?

Interesting that you are losing them to mold. I've never germinated them, myself. If this happened to me, I would probably spray their humidity dome with a thyme essential oil diluted in water to see if that takes care of the mold or not. Good luck.

I wouldn’t say I am losing them yet! There were 2 small patches at the last check, still a while before they have me

I will look into thyme oil, it looks like quite useful stuff generally. Would you recommend a specific type? Would they all work? From what I can see there are 4 variations, all with quite different effects.

Pics?

The first little bit of roots on some varieties looks very much like mold. I got worried the first time I saw that, but nearly all the little puffs became seedlings.

h202 works well and probably won't hurt the seedlings, if in fact, it is mold.

Pics

Attached are pics of the contaminated bridgessii and peruvianus trays (Day 11).

Pic 1: Bridgessii
Pic 2: Peruvianus

The parts with red squares round them are the main points of contamination, there is a bit more than can be seen easily in my photographs.

The green squares are most my little trichocereus babies so far There are a few more poking a little bit of white out of their shells but they are still too small to see in the photos.

Pachanoi tray has not been shown as the contamination is still very small and their are no seeds germinating yet it seems.

have to second acolon5's suggestion. very dilute h2o2 solution has been used to combat mold of various germinating cacti seedlings. seeds have been washed in h2o2 prior to sowing in oven baked media and hence watered with 10 to 20 ml h2o2 3% per liter h2o from the bottom of the container. works a treat!

You could make up a type of 'Cheshunt compound' using Copper sulphate and sodium (Bi) carbonate, mix together 1:2 or 1:3 and then add to water - it works well as an anti fungal without damaging plants.

Bit of an update…

The contamination seems to have disappeared for the moment, and there has been some good action in germination, if rather slow, but the weather hasn’t been too warm here the past 2 weeks.

So far have 9 Pachanoi / 15 Bridgessii / 10 Peruvianus babies, very pleased indeed! I still have more seeds left to play with as well!

Hopefully they will all get to a size where I can expose them to dryer conditions before it appears again. If it reappears I may have a play with diluted H2O2 solution as I can probably get hold of some from friends who work with hair.

i dont see anything in the pics to warrant worry, or spraying fungicide