germinating indoors

v1rtu0s1ty(5a)March 12, 2011

Hi. I just finished building a rack for my plants. I've also added 2 flourescent lights per shelf totalling to 80w. The tray I used has a transparent cover. I soaked the medium really well. Placed the seeds on top, tapped the seeds, misted the seeds then replaced the transparent cover. Oh, this is my first time doing this.

Last night, I set them to turn on from 12am to 8am. Is that good enough? When will I mist them again? Do they have to be transplanted or can I transplant them directly to the ground when they're 3-4 inches tall(hardening included)?


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rhizo_1 (North AL) zone 7

Why aren't you using your lights during the daytime, so that the seedlings can have some dark time? Plants a darn cycle. We use artificial lighting inside to add to sometimes meager sunlight available to these seedlings inside. We can add to the number of hours, too. I really can't speak the hours, though, as my transplants are put outside not too long after they've germinated. I don't need lights inside.

Are your flats heated by either heating mats or heating cables?

Did you sow the seeds directly into the seedling flat or in individual containers of some kind. I've always performed the former. Sowing them very closely in rows facilitates the transplanting into cell packs. If they are germinating directly into the flat, you'll need to transplant them before they get to be 3-4 inches tall. Unless I am missing something about your process.

We can't answer your question about misting or watering your flats. That depends upon several factors: type of potting medium, if the soil is heated or not, temperature and humidity of the room, how close the lights are to the surface of the flats, etc. It's important that the flats never dry out, and not just on the surface. Don't forget that you have a root system developing and adequate moisture must be available. Poke around in the medium with a pencil or finger to determine the moisture level and water accordingly. Misting may not be sufficient. Do you have a fogging nozzle?

I sow in flats to save room. I can plant hundreds of seeds in each flat, depending upon the varieties. Once they have germinated nicely, I turn off the heat, take off any coverings I may have added, and begin the transplanting process. Since many varieties of plants are in the same flat, and they germinate and develop at different rates, there's never any huge rush to get them all done at once. The cell packs are prepped outside, and taken outside to the 'holding area'. Then I carry the one or two or three seedling flats and begin transplanting. All of the flats will be able to be outside full time by the time I'm at this stage. I never worry about the seedlings unless the night time temps fall below about 35. I've got several transplanted flats outside now, in Northern Alabama, where the night time temps are still dipping into the low 30's.

Most of my cell packs fit 36 cells to the tray and I usually do anywhere from 10 to 20 trays. I use a coarse textured planting medium in those cell packs, as opposed to the germination medium I'll use in the germination flat. That way, the plants are extremely happy to stay put (and grow like crazy) until I'm ready to get planting in the ground.

If you've sown directly into some kind of little containers (like the cell packs) then you won't have to transplant again until they go directly into the ground.

    Bookmark   March 13, 2011 at 8:56AM
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ken_adrian Adrian MI cold Z5

16 hours on.. 8 off.. and if you can work an on/off cycle during the dark .. it had been suggested to me.. that it will trick the plants into thinking that the lights are on 24 hours ...

i started with two lights per shelf.. then went to 4 lights.... for higher intensity ...

and the lights should be about 2 to 4 inches from the plants.. once they get going .... again.. its about intensity ...

if you are growing a stout short healthy plant.. that indicates your intensity is spot on ...

if you start getting scraggly plants that are thin.. and reaching or leaning toward the light.. that would indicate that the light is not intense enough ...

you water when they need water ...

transplanting a 3 to 4 inch plant from a tray of many.. will be near impossible since the roots will be so inter-twined that you may do too much damage ... that is why they are potted up ...

look for 6 oz plastic dixie cups.. slice drainage on the bottom edge .... transplant at 4 or 6 leaf size ... big enough to grab.. but small enough that the roots are not extreme ...

recalling z5 ... if like mine.. your last frost date is 6/1 .... thats a long time from now.. to hope they remain under 3 or 4 inches ... which btw .. points out that you did not mention WHAT YOU ARE GERMINATING .... might help to know that ....

i used to run mine at night .... to use the heat for the house which was generated from the ballasts ... why waste it when the house was otherwise warm ... and the pictured setup was in the basement.. so they had their dark period.. if in fact those hosta seedlings needed a dark period ....

one issue you did not address .. is how cold the soil will get .... cold damp soil can be a big problem with seedlings ... many peeps use a heat mat .... if doing this in a cold area.. like a basement ... middle picture.. under the tray .. the condensation on the milk jugs is caused by the heat mat you can barely see under them .... 72 degrees constant ... beermaking store to germinate some grain or whatever ...

if you see any molds or mildew developing.. ask me about sterilizing the media


cant wait for gal to tell you to ignore everything i said ..

    Bookmark   March 13, 2011 at 10:20AM
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Growing up, my dad always advised me, "take it with a grain of salt", and that was well before the internet. Al

    Bookmark   March 13, 2011 at 11:18AM
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ken_adrian Adrian MI cold Z5

hey al ...

if you are referring to the flash on confusing the plants into think the lights are on 24 hours .. i agree with you ... and it probably all boils down to the fact that plants do NOT think, and ergo.. can not be confused ... lol ...

but if your timer has 2 extra triggers ... why not do it ... eh???

all i know is there is little difference between 16 hours and 24 hours.. so saving the much electric cost is worthwhile ..

but i doubt.. that with 2 bulbs.. that 8 hours will be enough ... and dont forget the distance from the leaf to the bulb .... because that is the other side of the intensity coin ....


    Bookmark   March 13, 2011 at 2:30PM
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After reading your responses, I made few modifications. I added christmas lights which generates enough heat. It will act as a heat mat. It's not LED-based since they don't produce heat. It's filament(tungsten based). One strip is 48 watts. About the florescent lighting, it's 80watt per shelf.

I have total of 4 trays. I have 3 72 cell trays and another tray which only has 25 cells. One of the 72 cell tray is still empty.

rud cherry brandy
murraya exotica
penstemon red riding hood
forgot the other ones

Here are the pics after the modification

Thanks everyone for all the tips/advice! I really appreciate it. :)

    Bookmark   March 13, 2011 at 5:07PM
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Forgot to mention, I also changed the time. It's now from 8am to 11pm.

    Bookmark   March 13, 2011 at 5:12PM
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mxk3(Zone 6 SE MI)

I germinate under fluoro. lights, and I run them 24 hours during germination.

After germination, I place on a different rack on the cart, and then run the lights approx. 16 hours for the seedlings - I feel they do benefit from darkness each day.

So, I've got one rack for germination running 24 hours, the other two or three racks running 16 hours. I have the 16-hour racks on one line on a timer, and the other one plugged right into the socket.

Works for me, and I've been at this a long time :0)

Personally, I would be nervous about the set up you have going there. Having plastic trays setting directly atop lightbulbs is a fire waiting to happen; at the least, a plastic meltdown. Traditional heat mats have a thin wire "cage" or bars that the trays sit on top of, the trays aren't directly on the heat source.

If you've got fluoro. lights running 24-hours RIGHT ABOVE the trays you shouldn't need bottom heat. Those flouros. will generate the heat for you. I do use a thermometer to lay on top of the trays to make sure I'm not overcooking or undercooking, I adjust the height of the lights depending on the germ. temp I want. I realize soil temp is different than air temp, but I'm pretty good at knowing the target ranges I'm shooting for. I can get the thermometer on top of the trays up around 90 if the lights are really close - that is more than enough heat for germination (and actually too much - if it reads that high, the lights get raised).

    Bookmark   March 14, 2011 at 8:50AM
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ken_adrian Adrian MI cold Z5

have you actually put a thermometer in there without the xmas lights ... to check the temp after 12 hours???

you did not mention you had it enclosed.. with such.. you might not need the bottom heat ... especially if you complete the enclosure a little more ...

but then you have to make sure it doesnt get too hot ...

otherwise.. looks like you are on the right track ...


    Bookmark   March 14, 2011 at 10:29AM
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Ok, I will put a temperature reader later. I'm still on bed, looks like I hurt my back after doing heavy dead lifts last night.

Yesterday, after 5 hours, I placed my hand inside the shelf and my estimate is that temperature is around 65-68f.

The shelf is not totally covered. There are openings on top, bottom and sides. I also hold one bulb for 3-4 mins and it wasn't strong enough to hurt me. There are 70 bulbs in one strip. One strip is 48 watts. Each bulb is at 1.45 watts. For each 72 cell tray, I only have 10 bulbs underneath it totaling to 14 watts.

Thanks again! :)

    Bookmark   March 14, 2011 at 10:53AM
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ken_adrian Adrian MI cold Z5

under 70 is a bit cool for FAST germination.. but sooner or later it will come ...

i used to put them on top of the fridge.. due to heat up there ... but i heard that newer fridges do not put out the heat ...

frankly.. i had more problems after germination.. lol ...

hope your back gets better.. before the nice weather arrives


    Bookmark   March 14, 2011 at 12:32PM
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after 48 hours, I am seeing germinations :)

here is one from salvia coccinea. Took this shot about an hour ago.

    Bookmark   March 14, 2011 at 1:34PM
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rhizo_1 (North AL) zone 7

It's during the Calvin Cycle (dark cycle) that plants are able to turn CO2 into carbohydrates. Light AND dark periods are necessary for normal plant growth and development.

Nice set-up, but I would remove those Xmas lights, too. It scares me.

You'll have plenty of time to worry about bottom heat for next year. I've always used heating cables...because that's what we used in my university courses, and what I used when I was growing hundreds of thousands of bedding plants professionally. They're inexpensive and efficient.

Bottom heat accelerates the germination rate pretty significantly, which then reduces the time needed for flat covers or wrappings. The high humidity levels can cause problems with diseases.

The need for extra warmth will cease once germination occurs, unless you have your set-up in a very cold location in a very cold climate. You should leave the lights on, of course, but open the flaps and even consider a small fan for air circulation. Or, as I mentioned in my earlier post, you can take introduce your plants slowly to the great outdoors. With so few flats to tote around, you can move them around a bit at first, so that they are not exposed to a full day of direct sun all at once.

Speaking of next year, I'm going to have my husband make a couple of wooden germination flats for me. I've been using the plastic ones but I think the wood will work better with the heating cable I like to use. The cable is buried inside the flats; an in-line thermostat keeps the soil temps at around 72 or so.

It was a great weekend for transplanting here. I ended up with 18 flats of transplants, more than I told myself I was going to do this year. Our estimated last frost date around here is mid-April, I think, so these will have over a month to outgrow their cell packs, lol.

I surely wish you luck and good fun in your first endeavor. Remember, for every 50 people you ask to describe their procedures, you'll get 50 different methods! If you gather enough good information, you'll be able to come up with a system that works for you.

    Bookmark   March 14, 2011 at 1:52PM
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donnabaskets(Zone 8a, Central MS)

A lesson I learned the hard way early on is that you want to take that lid off the seedlings almost immediately after the first two leaves emerge. Otherwise, you run a high rsk of damping off.

And, as Ken said, resist the temptation to over water. If the seedlings are indoors, once a week is probably plenty enough.

    Bookmark   March 14, 2011 at 9:11PM
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Thanks for all the advice.

After 3 hours installing the temperature reader, the temperature was 68.7F. I saw more seeds sprouting. Looks like it's their dream temp. :) What do you think about this temp? Should I cover the shelf more to prevent cold air in?

I'll make sure I don't over water. I noticed condensation is doing the watering for them. I'll also make sure to remove the lid once I see the cotyledons.

    Bookmark   March 14, 2011 at 11:15PM
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I meant, it took me only a minute to install the temperature reader. After 3 hours, I looked at it and it was at 68.7f. :)

    Bookmark   March 14, 2011 at 11:34PM
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rhizo_1 (North AL) zone 7

Is that the soil temp or the air temp? If soil, it's within the ideal range, for sure. But even if your temperature reader is registering the air, I'd not monkey around too much with anything, since you seem to be getting some good germination!

About the watering...just be sure that the whole soil volume is getting watered and not just the top layer. Those roots will grow down rapidly, as long as the medium is porous and full of oxygen filled pore spaces. Underwatering brand new seedlings can be just as detrimental as overwatering. OOOH, those dreaded damping off diseases!

    Bookmark   March 15, 2011 at 3:50PM
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ken_adrian Adrian MI cold Z5

the problem with tenting..

the upside.. it increases heat in a cold basement ..

the downside is the dead air ... without air movement .. which then could lead to too much trapped moisture.. and dampoff .. root rots.. or mildews ..

its a real catch 22 ...

i think rhiz mentioned a small fan for air movement ... been there.. done that ...

perhaps you have it enclosed enough.. and should not over-think it more??? I DO NOT KNOW ...

if you think about what goes on.. out in the garden .. these things are usually very hardy ... the problems really start ... when we start trying to manipulate all the variables .. and start screwing up how easy it can all be ..

you have to CONSIDER all the variables.. but it does not follow that you have to act on them all ... e.g. .. a seed needs a lot of dampness.. to soften the coat ... and initiate germ. .. so the soil has to be pretty damp ... but once we move from the seed .. the roots need air.. as much as water.. and if the soil does not start drying A BIT(!!!) ... then the baby roots can rot ... again.. a catch 22 ...

ambient humidity.. in a house with a forced air furnace... is necessary .... but not if it gets so high.. that mildews start on the soil ... sunlight outdoors usually stop or retard that.. but you dont have that here ... a variable.. a consideration.. and something to watch for ...

i hope you got rid of the xmas lights.. if you have germination.. then the added bottom heat is probably a non-starter ...


    Bookmark   March 15, 2011 at 4:20PM
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Thanks ken and rhiz for the advice. I took the lid off today and guess what I found out :)

Under 3 days, they have cotyledons now.

Hopefully with the lids off, I'll still see germination.

By the way, I changed the way I placed the tray over the xmas lights. The tray doesn't touch the lights anymore.

    Bookmark   March 15, 2011 at 5:56PM
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I read your first post again specifically the last sentence. I would like to confirm that there is no need for me to transplant to a bigger container since I am using cell packs. I also would like to confirm that they can go directly to the ground. If so, am I correct that I should transplant them when danger of frost is gone?


    Bookmark   March 17, 2011 at 9:58AM
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ken_adrian Adrian MI cold Z5

looks great so far ...

one observation.. the cells in back look like they are drying.. and ones in front sodden ... water management is your next hurdle ... perhaps it is just the pic ...

there is a media actually made for seed starting ... you might want to look into that in the future ...

keep us posted..


    Bookmark   March 17, 2011 at 3:42PM
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ken_adrian Adrian MI cold Z5

I also would like to confirm that they can go directly to the ground. If so, am I correct that I should transplant them when danger of frost is gone?


are you all up to date on HARDENING OFF .. to both temp and sunlight???

and good luck on never transplanting.. whether or not they out grow the cell pack.. is a simple function of whether or not.. you timed the planting out perfectly ... if you started them a month earlier than the weather will allow them outdoors.. you MIGHT need to figure something out ...

also.. the last two weeks.. they should probably be out to the garage ... increasing light .. and tempering to ambient temps ...


    Bookmark   March 19, 2011 at 9:01AM
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I was about to ask if I can start bringing those tiny seedlings out. I think they're still very small and hasn't shown the true leaves yet.

Thanks for the idea about the garage. I'm thinking of putting them outdoors but placing them under a table so they don't get direct sunlight or prolly use my black mosquito screen as a shade.

    Bookmark   March 19, 2011 at 11:52AM
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ken_adrian Adrian MI cold Z5

you were thinking about doing that when????

in mid may????

my garage faces due west .... i could open the door and leave them there in the doorway .. in bright shade all day..until late in the afternoon and evening ... by which time.. the sun would be weaker anyway .... and then shut the door for the night ... to keep out the aminals ...


    Bookmark   March 20, 2011 at 2:09PM
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rhizo_1 (North AL) zone 7

Do we know your location? I'm in the upper mid-South with an average last frost date of around April 15th. I've had my seedlings outside for a week now, even with one near freezing night. They were only about an inch or so tall at the time, but they all took it like little champs, lol! They get full sun until about noonish, when they are shaded by the house. I'll move them to where they get full sun all day long when I get around to it....maybe tomorrow.

Oh, I just saw your question about transplanting....

I'd certainly wait until all chances of frost are over AND until your plants have a good root system going on within that cell pack. If your planting mix is nice and porous, the roots will develop rapidly. If it's on the mucky side, it might be slow going.

    Bookmark   March 20, 2011 at 5:09PM
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you were thinking about doing that when????

in mid may????

I'm thinking around transplanting them last week of May. It's because for 3 straight years, I've had 98% germination success with direct sowing seeds of zinnia/castor beans/cosmos/cleome around second week of May. I was hoping that when I transplant those plants(hardened) I'm growing indoors during that timeframe, it will make it.

rhizo, I'm in northwest illinois about 20 miles east of Rockford, about 15 miles from south border of Wisconsin.

    Bookmark   March 20, 2011 at 5:28PM
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ken_adrian Adrian MI cold Z5

seeds and babes.. have differing ability to cold weather... more tolerance

but big huge fresh leaves from inside the house have another ... less tolerance ...

presuming you have a bazillion of them... plant in one week intervals from mid may until mid june... so if you lose the first batch.. so be it..

i presume you will have many ...

think of planting groups of 3.. but instead of planting all 3 at once.. plant one in each of a dozen spots.. then a week later.. add a second to the eventual 3... and then the last week.. add the third ...

so many options.. so little time.. lol ..

you made it sound.. like now that they germinated.. you were going to throw them out the door ... lol .. been there done that .. lol ..

experiment.. take notes.. the learning is in the experiment... not just in the execution ...

throw in some extra seed when you plant the first set ... if you saved any as a failsafe ...


    Bookmark   March 21, 2011 at 1:45PM
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Sure will do.

Check out my link below for an update about my growing indoors.


Here is a link that might be useful: Growing Indoors

    Bookmark   March 27, 2011 at 9:38PM
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