Vermiculite Topping - Yea or Nay

[FourOaks]

As of late I have been growing my seed starting operation, and need some input.

Im wanting to do away with using Humidity Domes. In short, they cost money. As it is, I have run out of domes, need to sow a bunch more flats, and dont want to buy more.

So, does vermiculite just help hold in moisture to the mix? Can you get by with just topping with V. and not worry about a Dome or Clear Wrap?

I have seen large commercial operations that obviously dont use any sort of covering. But, they have the Humidity thru the roof, and they often use a very quick draining medium that is watered daily.

So what are my options?

[Worth1]

Plant the seeds about 1/8 deep0and keep the soil moist with a sprayer till they sprout.
No need for fancy stuff.

[Nan_PA_6b]

I don't use any covering, but I'm careful to keep the soil constantly moist. I add a dash of cinnamon on the surface to inhibit fungus.

Nan

[Cole_Robbie]

Can you get by with just topping with V. and not worry about a Dome or Clear Wrap?

That's what I do. I spray down the flats every day to keep them moist. I like it that I can see from a distance when the vermiculite dries out. It changes color and moves when water hits it.

Even when I buy actual seed-starting mix, unless it is Light Warrior, the top will crust over and block the sprouts. That probably happens to me more because I try to sprout seeds at high temperatures. I just had my marigolds pop up after 48 hours and my mustard greens beat them by about half a day.

[FourOaks]

Cole... any idea what grade of V.??

Not that it would do much good, but the 4 Cu. Ft. bag I just bought doesnt say what grade. The pieces are probably 1/8 inch, give or take.

Ill have to look closer at the bag, to make sure I didnt overlook the size/grade.

[Cole_Robbie]

I just use vermiculite insulation from Menard's. It is more fine than coarse. If you have seeds that take a long time to sprout, it can grow algae on top, depending on the nutrients in your mix. The more coarse vermiculite would I think grow less algae, but it has never been a problem for me.

[Greatgardens]

I've been using horticultural grade vermiculite as a very fine topping for the past several seasons. It really seems to improve things for me. I perhaps end up with the same percent germination, but the germination is more uniform. I don't "bury" my seeds -- just press them lightly into the planting mix and then cover with V.

I use a plastic lid to loosely cover my trays (due to heat build-up if covered tightly). And I believe that the V. also helps maintain moisture. (I also use some V. to "lighten up" my planting mix which is Burpee Organic Seed Starting Mix.) On sale this week at Menards for $2.77/8 qt bag. So yes, judicious use of V. is a good thing, IMO.

@NAN PA 6b: Cinnamon? I'll have to try that. Never heard of it before!

-GG

[FourOaks]

Originally Posted by Greatgardens

I don't "bury" my seeds -- just press them lightly into the planting mix and then cover with V.
-GG

So thats pretty much what I did. I filled my flats, watered, used another flat on top to press the soil down. Layed down the seeds, then topped with V. Gave a very light sprinkle of warm water.

Some have domes, some dont. So we shall see.

[Salsacharley]

You can stretch a sheet of plastic wrap across the top of your trays for the first couple of days to keep the humidity up instead of using domes. You have to remove it as soon as you have sprouts.

[FourOaks]

Originally Posted by Salsacharley

You can stretch a sheet of plastic wrap across the top of your trays for the first couple of days to keep the humidity up instead of using domes. You have to remove it as soon as you have sprouts.

True. I just wanted to get away from that.

[FourOaks]

Just wanted to update this a bit. As noted above I have started topping with just Vermiculite. And so far the results are promising.

I do like with the V. that you can just look at it, and pretty well gauge how moist the underlying mix is. At first I would scoot some out of the way, just being curious, and yes the seed starting mix would be moist.

So far I have had good luck with seed starting in both 1801s and in 1204's. Since I just started using the 512 Plug and 84 Plug trays, I havent had any seeds pop up yet. Those should start in just a few days. But I dont see any reason why I should have any troubles.

I will add that with the 512 Plug Trays, I have been watering twice daily with a pump sprayer on a very fine mist.

[FourOaks]

So, some troubles have cropped up with the 512 Cell Plug Trays. I keep having keeps migrate UP thru the Vermiculite top layer. Im thinking just topping with my regular mix might be better.

For seedlings I have been mixing half peat, half vermiculite. I fill my cells, press down, seed, spray some water, top with V. and spray again. But after a couple more sprays the seeds starting coming to the surface.

Anyone have this issue?

[Nan_PA_6b]

I bottom water to keep the seeds at the proper depth.

Nan

[clkeiper]

You need a softer spray pattern. do you have a water breaker on a wand? what color is it? If I recall red is coarse and yellow is a much smaller hole and fine spray. I also have a purple one which is the finest. I also have a "y" fitting on the end of my hose that I can adjust the flow rate going through the spray head. there is also a mist nozzle you can try for watering. I also have a wonder waterer which is nice to water seedlings with. I started topping with vermiculite this year which has resulted in a much better germination of the rosemary.

[FourOaks]

For seedlings I have a Dramm 1000PL. But for the Plug trays I have been using a pump sprayer, with a very fine spray. I have been intending to order a "Fogg-It" nozzle for the plugs, but for now the pump sprayer works.

This evening I sprinkled some extra seedling mix on top before misting. Just to help anchor the seeds.

On a positive note, I did notice the Serranos I sowed a few days back are starting to surface. Those seeds did seem to stay put.