A fair number (15%-20%) of my seedlings are dying off just after the true leaves are forming. I
The following has sometimes worked for me:
Also, if you do not have a “zillion” seedlings, I recommend using a hydrogen peroxide/water mixture whenever you water.
I thought about using H2O2, but wasn’t sure what concetration to use. Also, I read that it didn’t work for others. But I will give it a try. I only have about 50 seedings so far so I certainly could water them with H2O2/water mix.
Are these 50 seedlings from the same cross/parents, Paul?
I’ve used 2 tablespoons of H2O2 in a one liter spray bottle. I just sprayed every other day. I didn’t use this spray to replace regular watering. It was more of a top dressing to kill off bacteria and fungus. That was for Japanese Maple seedlings and seemed to work fairly well.
About 75% are from one seed parent (Hawkeye Belle x William Booth) with 4 different pollen parents and OP seeds of it. About halve of these are from one cross though with an (R.arkansana OP). The other 25% are from one cross each of 5 different seed parents.
Here’s an update on the my dealings with damping off.
Nearly all of the seedlings that I put one or two drops of 3% peroxide on survived, but just barely. The leaves turned yellow and they almost died. I gave them a good rinsing with water and then fertilized them with a weak solution of Miricle Grow. They have rebounded well and there are flowers buds on a couple of them.
I also used started using a diluted peroxide solution spray. When I plant my seeds I plant them directly into 3" pots and I give these a pots a good spraying when I do. Since doing that I have had very little problem with damping off.