I think it depends on the environment outside the cover, if it is the humidity of a greenhouse, okay, but I have started tuberhybrida seedlings in the house and will keep them 'under cover', so to speak, until they are a couple of inches tall and ready to move on because the house is well heated this time of year. I would wipe off the inside of the cover, if the moisture is a lot it could drop on the plantlets and that might cause rot.

Thanks for the response. They are not in a green house. They are under lights on shelves in my studio/growroom, which I keep pretty cool (60F). But the lighted shelves are blanketed with a mylar blanket and the heat from the fluorescents keeps the top shelf about 75F. I will plan on just leaving them in the germination tray on that top shelf until They get large enough that they need to be transplanted.

I sure am hoping I can keep them alive and growing!

Hello - here is a picture of some of my begonia seedlings that was taken this morning after I read your post. The tray on the left that is covered with saran wrap has tuberous begonia seedlings that have been transplanted once into a 'community flat' and as you can see there are droplets of water on the plastic - this will not cause rot if the soil the seedlings are growing in is not too wet to begin with. The opened ziploc bags on the right have fibrous begonia seedings growing in them, and they have reached the age and size where outside air is slowly being allowed to reach the seedlings. The key here is to do it s-l-o-w-l-y, opening the plastic bags for a few hours a day at first, getting them acclimated to a drier atmosphere. If you completely remove the covering on small begonia seedlings in your home{{gwi:807}} they will probably dry up and disapear overnight even if the soil is moist. My seedlings are growing in my basement under fluorescent lights that are lit for 14 hours a day on a heat mat set at 72 - 75 degrees, now that they have been growing strongly for the last couple of months they will start to get very dilute (1/4 strength) fertilizer with almost every watering - they like to be fed, but don't over do it with tender young seedlings! Hope this helps, good luck to you.

- Jeb

This post was edited by jebfarm on Fri, Feb 8, 13 at 13:37

Thanks Jebfarm,

Your seedlings look great!

I think I will cover mine up again. I took off the cover about 4 days ago because I was getting a lot of algae growth and I was afraid it would smother the tiny little guys.

Because they are the top shelf and the shelves are usually covered with a mylar blanket, it is certainly more humid than the rest of the room, and I dont have forced air heat in the room to dry them out.

Yesterday I transplanted each of them into a separate 3oz cup, doing my best to leave behind any of the algae covered soil, but I left them uncovered.

Do you have problems with algae? I have some every year. I meant to buy some fine chicken grit to top the soil with this year, but didnt get around to it. I have heard that that helps keep the stuff from forming.

Generally, algae forms from too much moisture and/or too much light. I've heard of some remedies, I'm trying to remember where I read about them.

I found some notes on algae deterrents, but no cures. One deterrent is to use a Physan 20 solution ( 2 teaspoons to l gal. of water) to wet your sowing mix. A couple of old-fashioned ideas are to have copper pennies in the vicinity of your seed pans and also damp newpapers. Newsprint has or used to have something which could deter algae. Also, found a mention of mercuric chloride in solution and potassium permanganate in distilled water. I haven't tried any of these on seeds but I do use the Physan solution to pre-soak sphagnum moss to deter algae, it's safe for orchid growers so I think it is safe for begonia cuttings.

Thank you woebegonia,

Exacty - moisture and light - neither of which I can really cut back on in this situation. I only seem to be getting it on the really slow growing seedlings, begonias and lisianthus. I'm guessing it is because everything else has been potted up pretty quickly.

I'll look into the Physan 20, mercuric chloride sounds way to toxic if it is a derivation of mercury.