how much moisture

should be on the dome when using a seedling heat mat? Right now it is about 1/2 full of seedlings and a little less than 1/4 of the lid is propped open as the directions say. the starting mix feels damp. I do intend to start more seeds in the next few days. there is also no light on them at this time but I am set up to use lights, should I turn them on? or wait until they sprout?
Thanks in advance.

Hi NoQ.

I've learned that you want to see a fine mist on the inside of your dome. If you see actual drops your soil is too wet. If you don't see any mist at all your soil isn't damp enough. Or you might try tightening the dome a little. Alternately some folks punch a few holes in the dome as opposed to leaving it cracked. You'll soon find out what works best for you, just remember you're looking for a fine mist.

As far as the lighting, you'll want to have your lights on when you start the seeds. They're going to "reach for" the light, so those seeds that require light for germination - which is most of them - will benefit from having light from the very start. (LOL I just heard a voice in my ear saying, "walk into the light." I guess seedlings do that exact thing!)

I just started some seed trays over the weekend. They are on a heat mat and I have a light for them that I've been keeping on for about 14-16 hours each day (turn it off while I sleep at night). Is this long enough, or should I just be keeping it on 24 hours a day at this point?

14-16 hrs should be fine, that's what I do with my seedlings. The other important thing is once they germinate, you need to make sure that the lights are no more than a few inches above the tops of the seedlings, otherwise they'll tend to get leggy. And take away the heat mat once they germinate too since the bottom heat will also tend to make them leggy.

good to know - thanks! how do you generally handle it if you have different types of seeds in the same tray that germinate at different times. for instance, i have some bush morning glory & swamp hibiscus already germinating (2-3 days), but nothing else in the tray is (cannas, other hibiscus, etc).

I usually plant my seeds in the little 6-packs, each 6-pack gets one type of seed in it and then I put a bunch of 6-packs into each tray. I always leave a space for at least one extra tray on my seed starting shelf, and once a decent number of seeds in an individual 6-pack have germinated then it moves to the open tray which doesn't have the heat mat under it. So by shuffling the 6-packs around I'm able to keep the things that haven't germinated yet on the heat mat and the ones that have germinated off of it (everything is under lights).

That's a great plan - I'll have to try that in the future. Thanks for the tip!

There was mostly a fine mist and drops at the top edges of the dome. but this morning there was only a small amount of moisture in one corner (drops) I plan on starting more seeds later today when my son is napping.

Jenepat you just made a germination move that almost all of us has done once and usually only once. I think we've all tried to save space by putting more than one type of seed in a container and it almost always backfires because nothing every sprouts at the same time. I even hesitate putting different types of the same seed in one container (ex. 4 different petunias) because I've seen germination times vary up to a week from different venders. I say I hesitate, but usually I do it anyway, LOL. Like I said...there is only so much space on those mats!

Sounds like you're about right noQ. If you see the drops, just give it a little more air, and when you don't see any moisture at all it's time to give the flat a little drink (preferably from the bottom which will help prevent damp-off.

I have a question about the moisture now. I have one tray filled with jiffy pellets and another tray with peat pots filled with peat soiless mix. To prep both of these for sowing, I "bottom watered" the entire tray before sowing the seeds. However, this made both the pellets and peat pots extremely moist, which in turn made a ton of condensation on my humidity dome. Only today (on the 5th day since getting it set up) does the condensation seem to be thinning out. I pour off any collected condensation each time I remove the lid to check on the seedlings.

How do you guys initially get your trays moist w/o leaving them so wet?

I'm going to have to let some one else answer that one for you as I use neither peat pots nor pellets. I tried the peat once, but just didn't have much luck with them. When just using soil I pre-wet it in a bowl or some other larger container before filling my trays. Then after the initial wetting and sowing I water from the bottom.

Ah, so pre-wetting in the bowl I'm sure you can have a lot more control over how moist it gets since you can just mix in more dry soil if you need to. And it all gets mixed in nicely too. Great idea!

Still curious about the best way to handle the peat pellets & pots though...

Lala_Jane - got a question...so when you're watering your soil from the bottom, how do you keep it from getting too wet? I feel like by the time the top of the soil is damp, it's all pretty saturated? I'm worried about keeping them too moist...

Jenepat that can be a tough one but I've found that as time goes by it gets easier to gauge. If the holes on the bottom of the container are of pretty good size it doesn't take long so I stay with them 'til they're watered. I stick them in the tray of water until I see a small spot of water starting to show on top, then I take it out. After it sits for a couple of minutes the moisture will distribute itself throughout the rest of the container. The weight of the container is also a good guide. If I pick up a tray and if feels almost empty I know there's no moisture in it. After awhile you'll be able to notice how heavy (or light) a dry container feels verses one that has the right amount of moisture.

I hope that was at least a little help. Like so many aspects of gardening there's always a lot of trial and error before you figure out what works best for you. I know some people prefer to mist as opposed to bottom-water until the seedlings set deeper roots. I've had too many issues with damp-off and fungus gnats with top moisture so this system has proved the best for me.

Thank you so much - that is a huge help! I'm sure you're right that I will just have to see where I end up with the whole trial and error thing - but at least this gives me an idea of a good method to start my "trials" with.

Thanks again for all your help!

If you use the Deno's method, as it is called, none of the problems stated above would occur.

All that is, is to germinate seeds in moist kitchen paper towels, the stored in a ziplock baggie, either in the refrigerator (cold treatment) or on a shelf. When they have produced radicals (roots) make a hole with a pencil in the seeding flat and gently guide the roots into it using a tweezer. Leave the seed shell level with the surface, then cover the seed with additional seeding mix so it will be the depth recommended for that variety. This way you can space the plants in the flat and all are the same size, and variety. Or plant the germinated seed in small individual pots.

I am amazed how quickly seeds sprout in paper towels. No problems with fungus, damping off, or bugs as is often the case using soil.

Caption: Hibiscus seeds nicked soaked, then placed in paper towel germinated in 2 days. These were 3-year-old seeds that I had problem sprouting even when the seeds were new. .

Here is a flat of perennial Helianthus maximillian (Prairie Sunflower) seedling starte with the Deno method, then placed in the refrigerator of 1 week. Started them Feb 11 and they germinated March 3. I planted them 1" apart once they sprouted. Some have not broken the surface yet.