Catharanthus roseus is a tropical needing high temperatures to germinate, so you'll probably have more luck starting them inside...

Thank you for your comment, milo. Do you think they need total darkness?

Yes, you should give them total darkness if that's what is recommended on the instructions. As time goes by, before you check inside the tote, take it into unlit closet or room so that as you look inside, light doesn't shine directly on the containers.

Also, you should probably start them in containers that are solid color, not clear or see through.

When they are winter-sowed and are covered with soil, aren't they in total darkness?

I think when they suggest total darkness, they mean don't let the sun shine on the soil or through their containers. Perhaps sunlight penetrates soil somewhat, like sun through draperies.

I guess those are the types of seeds that need a very dark environment--super sensitive to light.

I like your tote bag idea. I have used a cardboard box inside of a closet.

Tansy, a cardboard box inside a closet is a great idea.

I am using one of those 18 gal, dark blue Sterilite containers. We call them totes here, maybe y'all call them something else.

Thank you for all the suggestions.

Well, I sowed the Catharanthus roseus (Periwinkle) seeds in blue plastic cups, placed them into a blue Sterilite plastic tote, put the lid on (because there is no place in my house, or on my property in which no light will penetrate) and left the tote in my office for 14 days.

Like a doofus, I completely forgot about the "maintaining lots of bottom heat" part of the instructions. So, when I checked them today (14 days later) none had germinated and a fuzzy mold had begun to grow in 1 of the cups.

Since I am not set up to sow inside, I have no source for the *bottom heat* these seeds need to germinate.

Should I put the tote outside (heat from the sun), keeping the lid on all the time until germination?
If I keep the lid on, will there be an issue with mold (there are two small holes under the handles in this tote, so some air flow does occur)?

Not sure what to do, and I have Pansy seeds that recommend excluding light as darkness is beneficial, also. So, I need to figure this out asap. I would really hate to lose the Periwinkle and the Pansys.

Thanks for any advice you can offer.

I'd try it again, but put a reminder in your office to open that tote every day so that a fresh bunch of air gets in. Or leave the top ajar. Check for germination at night with the lights off, but perhaps have a light in another room so you can see what you're doing but the soil will not get any light.

Maybe switch the tote for a cardboard box so more air gets in.

If you have a small fan in your office run it near the box to discourage the mold, and encourage fresh air.

If you don't have an electric means of providing bottom heat like a heating pad, maybe you could rig something up with hot water bottles which will hold heat for 9-10 hours. Detergent bottles, for instance can hold a lot of hot water and stay hot a long time. Use towels around the hot water bottles to keep the heat in your box, radiating up toward the plant trays.

I don't think you'd need continuous heat on the trays, as long as it warms up once a day.

To help discourage mold you can also put perlite or sand as the top layer.

Don't leave a heat pad or anything like that on while you are away from home. The hot water bottles are far safer.

You could make a routine where you change the water in the hot water bottles once a day when you do the air exchange.

I hope you get those periwinkles and pansies. Those are such great plants!

I would give them more time, because those germination days are just estimates. I've had seeds take over a year to germinate and come up in the same pots where they were originally planted!

Your main enemy will be mold because: damp, dark, warmth, lack of air = mold.

Can you try to germinate these seeds in pure peat moss? It's seed-friendly and discourages mold.