Algae/mold on top of seed flats

When you're growing seeds with a long germination period, how do you keep algae or mold from growing on top of the planting medium, but still keep the mix wet enough to germinate the seeds?

If you've got algae and mold growing I would guess that you're keeping things too wet. The other thing that might help is sterilizing your seed starting mix before you start--that will get rid of any mold spores that are in the soil before you start, and if you combine that with keeping things a little bit drier then that will hopefully minimize your problems.

I found that if the soilmix is compacted too much in the tray/pot, then it will take forever to dry out & you get the algae. Last year, in one tray I had pressed the seedstarting mix too much and the green algae appeared. It seemed to take a long time to dry out. The plants were not affected though. Once it was dried out a bit the germination continued.

The green algae doesn't hurt anything and I get alot of it on things that must be kept moist. I just stir the surface of the mist with a toothpick if it gets too think.

I started getting algae and mold when I planted my amaryllis bulbs this winter, so I started spraying them with some hydrogen peroxide in the water when the surface was getting dry, and eventually the algae/mold went away.

Drat I have a white fuzzy mold starting on one of my viola flats. What ratio of HP to water did you use perenniallyme?

I tried to use around 1 part hydrogen peroxide to 9 parts water, as that's what the concensus seemed to be, but I just eyeballed it. Good luck.
PS should also say I scraped off any visible algae/mold too.

PS. I've also been using this mixture to start my indoor seed flats and water them, and (knock on wood) so far, so good.

Thanks pereneniallyme. I'm scraping it off too where I can.

Perenniallyme -
Eureka! Thanks for posting that tip. And Avianut for posting the question. I've had this problem every year, especially trying to keep seeds damp that don't require covering with soil (like Aqueligia, etc). Have always used pre-sterilized germination mix and sterilized my APS and trays too. Question though - is city water ok for mixing with the hydrogen peroxide or should I be using distilled or sterilized water?

Hi Cindy. I'm certainly not an expert - just a beginner at starting seeds inside, and have gotten all my tips from DGers on various threads. It seems there are some purists who will use distilled water and even sterilize their wintersowing containers with bleach. I've been ok so far with city tap water and just washing my containers in hot soapy water, but it may be too early to tell.

Perenniallyme -
I had been using the same APS trays for years and since there are always little voids in the styrofoam, I always thought it best to sterilize with bleach. I'm branching off into using other containers as the APS trays are sometimes inconvenient (like waiting for the last row of seeds to germinate after everything else has been transplanted out of the things) and haven't gone the bleach route on the alternatives since they're plastic. I've never had damping off problems - just the algae.

When planting seeds I lightly cover them with vermiculite. Several seed catalogues suggest this method & it works great for me. No damping off or algae/mold. I also don't overwater. I soak my seeds in a liquid seaweed/hydrogen peroxide/water mix with excellent germination.

Cindy, I'm using mostly the plastic cells, but have a few of the styrofoam ones. Think I'd use bleach on those too in the future. I used one for trying to root some rhodo cuttings, and got mold. Could have also been from the wooden markers which I'll never use again, but I got rid of the mold with the hydrogen peroxide. (Still waiting for the cuttings to root, though, and it's been about 4 months.)

Perenniallyme -
I dug up a Rhodo branch this past fall. It was resting on the ground for the past couple of years and rooted (which I encouraged by trying to keep a rock on top of it). I cut off the branch and stuck it in a pot and put it in the cold frame for the winter. I'm interested to see if it's going to survive. It didn't cost me anything other than potting soil. My cold frame is more for holding over potted perennials or shrub suckers that I've dug up so it's taller than the traditional cold frames. Good luck on your cuttings.
You may be right about the wooden markers. I gave up on those because they rot pretty quickly.
Broots -
Usually I just sprinkle fine, dry germinating mix on top of those seeds that require covering. Maybe I need to go buy a bag of vermiculite. Is it something in that product that discourages algae growth?

New sproutign seeds are very susceptiable to damping off right at the soil line. Using a bit of vermicultite helps to keep the plants collars a bit dryer and help keep them from rotting.

Cindy, I'll bet your rhodo does fine since it has roots, but it's just a guess since I have no experience. I think I'll try your attached branch method of rooting in future, since I don't hold out a lot of hope for my rhodo cuttings.

Perenniallyme -
I was a total failure last year on dormant cuttings but I'm assuming your cuttings were semi-ripe? The limited stuff I've read indicated that azaleas (rhodos by association?) were supposed to be easy. Maybe that's not accurate??? Hey, I'm no expert - usually just fly by the seat of my pants. That's why I love shrub suckers - already rooted - and unless I really handle them badly, they live!

Cindy, I'm not sure what you mean by ripe. I cut them around the end of September, following instructions from somewhere, taking them from the north side, etc. Took the cover off to get rid of the mold and never put it back.....
Just thought of something I wanted to try but forgot about and hope I can find it again - some kind of cup-like contraption that you fill with wet moss or some such, and attach to a branch after scoring it. Like an easier way to root a live branch without having to bury it in the soil, which isn't always possible. Someone mentioned it somewhere on DG - maybe a month or two ago. If anyone knows what I'm talking about, please let us know.

PerennialMe. Ya take the branch and very carefully cut away at the outside edge in one small section about an inch to 2" long. You just srap at away that small section of bark til ya see the white.

Take a litel bit of peat moss, wet, it in yoru hand and wrign it out. Wrap it around the wound you made. They wrap a piece of plastic around that. They a piece of foil over that. Lot so wrapping. LOL

Then maybe once aweek remove the foil wrap and check to make sure the peat moss still damp. If it is put foil back on and ignore again. If it not. then cerefully just pour a little water fown from the top of the plastic, just enough to moisten the peat again.

It called air layering.

Thanks Starlight! Do you happen to know what those plastic contraptions are called that you can use to save yourself all the wrapping and unwrapping? A few people were recommending them a while ago. I just went looking through the propagation threads and couldn't find it.

Sorry, not off hand, I use saran wrap and foil. Did see the thread either to help ya out.

Perenniallyme -
I saw that contraption in a catalog just recently. I'm thinking Gardeners Supply but I could be wrong - I threw away the catalog because I get one just about every month. Starlight is right about the sphagnum and all if you don't want to spend much money.

Thanks Cindy. I'll go look for it. It sounded like the easy way out for a lazybones like me.

Perenniallyme, might this be what you are looking for?

http://www.leevalley.com/garden/page.aspx?c=2&cat=2,47236&p=46938

Thanks broots! That's exactly what I was looking for, and I have it saved now so I won't lose it. Have you tried them?

No I haven't tried them yet. They are on my 'to do list' along with a lot of other things. Please post back if they work for you.

I will, but it'll be a while. I'll probably order them in the spring.