Confused about proper starting containers for indoor seedlings

15 years ago

I read Nancy Bubel's Seed Starter's Handbook chapter and I checked YouTube for videos. I am still confused, so I came here to ask more experienced gardeners.

1. What exact type of container or tray do you start your seedlings in? (I see different types at the store. Some are flat peat pellets. Others are black flat trays with 72 container 2" deep pots (6 to a section) like the ones you see at the Home Depot garden center.)

2. Do you transplant your seedlings once the cotyledon pops up? If you do, then what type of container do you transplant into?

3. Do you only use grow lights with the second transplant attempt? Or do you use grow lights both times?

4. Do you water from the bottom or spray mist from the top?

Sort by:Oldest

Comments (12)

digdirt2
15 years ago
Check out these FAQs here:

I'm new to growing from seeds so how do I get started?

OK,my seedlings are growing,now what do I do?

Do I need lights for starting seeds?

What Types of Containers Can I Use for Seed Sowing?

They should answer all your questions. ;)

Dave
Karen Pease
15 years ago
1. The flat trays with many small pots. I don't like peat pellets.

2. "Do you transplant your seedlings once the cotyledon pops up?" - No. You only transplant plants when you have to -- when they outgrow their container or they're too crowded together. Transplanting is a shock to plants, so you avoid it insomuch as you can.

3. As soon as the plant is out of the soil, you want light to be there ready for it, and lots of it.

4. Bottom, absolutely. Wet stems and leaves are much more prone to disease. So is having a wet soil surface more prone to fungus. Bottom watering is more efficient and healthier.
Related Discussions
some ?'s about starting onions indoors
Q
Comments (5)
i always plant my seed in 4" X 6" containers and put the seed into rows, 8 or 9 per row going in the 4" direction, i use tweezers to put 1 seed in the right spot tedious but it works well. one year i just sprinkled seed to see the difference. i decided that sprinkling seed did not produce seedlings that developed as well as when i did rows. maybe they were too close? i went back to planting in rows. greenhouses have onions in containers that are very crowded and they seem to do ok as far as attaining a good size for planting out but i'm sure they over fertilize for the growth otherwise people may not buy them if the plants were small and thin. personally i prefer allowing the plants to have more room. i have 1 4' X 6" of red wing about 75-80 plants and 2 containers of copra about 150-160 plants. tom
...See More
This confuses me when starting seeds
Q
Comments (50)
Chandra, It is too early in March to trust the weather forecast and it certainly is too early to set out any warm-season crops without the use of Wall-o-Waters or other plant protectors. I've only planted out this early once (on March 9th that year) and had my plants survive. Even as far south as I am--about 120 miles south of OKC--I won't even consider transplanting any warm season plants into the ground until March 20th at the earliest, and my average last freeze date is March 27th or 28th, depending on which data you use. At our house last night/early this morning, for example, the forecast low was supposed to be 39, and we went down to 35 degrees at our house with a medium frost and our OK Mesonet station at Burneyville went down to 28 degrees. If I'd had warm-season plants in the ground already, or even outdoors in pots, they would have frosted and would be either dead or severely frozen back this morning. I know the frost was on the ground for at least 3 hours and tomato plants can't take that, and neither can peppers and other warm season plants. Yesterday afternoon, I carried ten flats of tomato plants into the well-insulated garage well before sunset and closed the door to help hold in the heat, so the cold night didn't affect them. I left the flats of pea, nasturtium and strawberry plants in the uninsulated potting shed and they are fine but the nasturtiums looked the slightest bit sulky when I moved them outside to the shed's little front porch this morning. The peas are going into the ground today. I've been watching the calendar carefully because peas can freeze in the low 20s and I feel fairly confident that in my area, we will not go any lower than the mid-20s from this point forward. I still feel like we will have more frost and more freezing nights here in southern Oklahoma, and certainly y'all will have them there in central Oklahoma as well. One important thing to remember is that frost can occur at temperatures higher than 32 degrees. At our house, we often have frost even when the air temperature is in the upper 30s. I don't remember having that happen in Fort Worth, but in Ft. Worth we often went from cold to hot just like that and winter was over. Here, in the spring, the daytime highs indicate winter has ended and spring has arrived, but the nights stay winter-cold until almost April, and sometimes beyond. Your potatoes in the ground will be fine. Even if you have some dieback of above-ground potato foliage from freezing temps or frost, they'll often resprout and produce, although sometimes they are damaged so badly that production is lower than it otherwise would have been. When I start putting warm-season crops in the ground, I'll post here and say so. As far as I know, no one here in my county has put any warm-season plants or seed in the ground yet. Some folks in far eastern and southeastern OK likely can plant warm-season crops before I can because they have their last freeze and last frost a few days before we do here. In general, folks in central OK don't put warm-season crops into the ground until April. (Some will plant earlier if they have a warmer microclimate or can use plant protectors like low tunnels, buckets to cover up plants, Wall-O-Waters, etc.) My experience covering up tomato plants and pepper plants with 5-gallon buckets on cold nights is that is only works about 50% of the time, so I just hold my plants in their cups longer and don't risk losing them to frost or a freeze. Remember that in central OK, your last freeze date doesn't even occur until somewhere between April 1st - April 10th at the earliest, and the average date is the "50%" date, meaning on that date you still have a 50% chance of having a night cold enough to damage or kill plants. The conventional wisdom says that to be safe, you should wait and plant your tomato plants two weeks after your average last freeze date, and in a climate where the heat is slower to arrive, I agree with that. However, since we are in a tremendous race to get good fruitset before the temperatures get too high here, there are not a lot of us who wait until two weeks after our average last frost date to plant. We have a hard enough time restraining ourselves from planting two weeks before our average last frost date. My personal experience here indicates that in my specific location in our county, we will have a freeze after our "average last freeze date" about 9 years out of 10. I've learned that the hard way. On the attached link, click on the freeze data to see the maps that show average (50%) last freeze data. There's also maps for a 90%, 70%, 30% chance, etc. This data generally represents 30 year averages, so it is as reliable as anything else we have. Dawn Here is a link that might be useful: Last Frost Data from the OCS
...See More
Indoor seed starting basic question
Q
Comments (8)
My own small, informal trials are enough to convince me of the value of using the "paramagnetic" volcanic powder. Back in the spring, I was starting several kinds of plants using a bagged potting soil my wife and I bought. I used that "growing medium" unamended, in sets of matched starter trays, except for those trays in which I'd added about 15% volcanic rock powder to the mixture. All those seedlings were started under grow lights. (I didn't take pictures of the results.) Somewhat over a week ago, I again used starting trays ("six packs") and matched the basic growing medium, the watering regime, and the lighting on the experimental and control trays. However, I made up my own starter medium as follows: 50% sphagnum peat moss; 30% worm castings; 20% perlite - well stirred. This, in itself, is a pretty rich mix because of the worm castings. One of the trays contains this mixture as such. The other has this mixture with about 12% volcanic rock powder stirred into it. I made up only two trays, and identified each one to be able to interpret my results. With each of the six packs, I filled each of the cells as close to the same level as I could. I planted each cell with two radish seeds from the same packet. I kept the trays on a bench in our greenhouse. Then I was careful to keep the watering and the light exposure the same. Seed germination took about 48 hours, on average - and the germination rate was pretty much the same, comparing the two six packs. The picture, taken eight days after planting the seeds, pretty much tells the story. The seedlings (on the left) with the volcanic powder in their growing medium are clearly doing better. I'd estimate the difference in vitality and growth to be maybe 20%, at this early stage. With my spring-time experiment, the difference seemed more marked - probably because the commercial growing medium was very basic and not high in nutrients (such as those the worm castings provide to the new mixture). With the spring experiments, the seedlings growing in the medium that included the volcanic rock powder did twice as well, in my assessment, in terms of vitality and size. However, I judged this difference not after eight days, but after a month or so. I was thinking some people who look at this thread might like to see a picture that conveys the benefit. While Paramount Growth Holdings is not yet retailing their product, other sources for this sort of volcanic rock powder in the U.S. and Canada might be available.
...See More
Confused about container planting
Q
Comments (3)
how big are they?? putting a tiny babe.. tissue culture plant.. or mini hosta.. into a large pot.. just doesnt seem to work ... im not sure i ever heard a reason why ... other than to say... they like to be a bit root bound.... i presume it has something to do with how water moves thru a media ... insuring proper flow.. drainage.. and perhaps nutrient availability ... especially on a commercial level ... and i dont really think it is only a hosta thing ... i dont see why you wouldnt get the same issues.. if you put a 4 leaf seedling of anything.. into a one gallon pot ... usually we see them going from cell packs.. to quarts ... to gallons .. and the price going up accordingly ... i see no issue going from a quart.. to a gal .... within the season.. the plant should fill the one gal by fall ... or perhaps you did something wrong ... you do want to give it room to expand the roots ... this is also why ... if you have some GIANT pot ... you might want to do a pot in pot system ... among other reasons [was that your post???] .... comparing pot culture with soil grown plants ... is hard to do ... as there are so many variables to take into account ... but once you put one plant in each.. i think you cant compared directly .. or predict.... also.. keep in mind... with a hosta.. it is what it is.. after it leafs out ... after that.. its growing roots and storing energy for next year .... dont expect it to increase in size ... as you might see with other perennials ... and especially annuals ... btw ... there is a container forum ... you might find other muses there ... it is a real art.. when it comes to long term container growing .... starting with the media ...and moving on from there ... ken
...See More
janbanks
15 years ago
Question for Karenrei - in terms of bottom watering... I have some seedlings in the 72 cell flats. Do I simply bottom water by lifting up the cells and pouring the water to the bottom of the tray? That seems logical but I fear it won't get the soil wet enough.
Thanks!
kistler
Original Author
15 years ago
Thanks for your responses. Great stuff! :) Okay then, here's what I'm planning to do. Please shout warning if I'm off-base.

I'm going to put a half and half mixture of potting soil with vermiculite into my 2" high 72 pot flat. I will fill each pot so there is only a 1/2" to the top. I'll do that so light can reach the plants better. Each pot will get one seed.

I will water from the bottom and cover the seeds with plastic until they start coming up. At that point I will remove the plastic cover and turn on the grow lights.

Once my plants look strong enough I'll harden them off. I will not pull them out of the pots until it's time to put them in the actual garden. That will be their only transplanting moment.

Sound good? ;)
hatchjon
15 years ago
"I will fill each pot so there is only a 1/2" to the top. I'll do that so light can reach the plants better."
I think it would be better to fill the cells to the top. The seedlings will have more room to spread their roots with the cells filled all the way. Also, I don't understand why half filling the pots will allow for more light?

Jon
Karen Pease
15 years ago
Question for Karenrei - in terms of bottom watering... I have some seedlings in the 72 cell flats. Do I simply bottom water by lifting up the cells and pouring the water to the bottom of the tray? That seems logical but I fear it won't get the soil wet enough. Thanks!

Yes, just lift up one group of cells (no need to lift it all up) and pour in water. Trust me, you can get them as wet as you want, anything from dry as a bone to a rot-your-plants-in-an-hour swamp. All that matters is how full you fill it.

I'm going to put a half and half mixture of potting soil with vermiculite into my 2" high 72 pot flat. I will fill each pot so there is only a 1/2" to the top. I'll do that so light can reach the plants better.

I agree with Hatchjon. I'll also add that loose soil (which is what you should fill them with -- don't manually compact it!) will get compacted somewhat on its own as you water. So if you start them at only half full, they'll end up at 1/3 full or so. Go ahead and fill them up full to give your little plants all the room they need to grow. :)

Apart from that, sounds good!
digdirt2
15 years ago
A couple of possible problems that are addressed in the FAQs here.

I'm going to put a half and half mixture of potting soil with vermiculite into my 2" high 72 pot flat.

Not potting soil. Using potting soil will almost guarantee you damp-off problems. Why potting soil is NOT used but soil-less mixes are is explained in detail in the FAQ I linked for you above. Soil-less potting mix or better yet, sterile seed starting mix is used for germinating seeds. They come with vermiculite already added.

I will fill each pot so there is only a 1/2" to the top. I'll do that so light can reach the plants better. Each pot will get one seed.

As others have said that doesn't improve the light any. If you use only 1 seed in each containers you will have empty cells because not all the seeds will germinate. If you want a higher rate of germination place at least 2 or more in each. This too is explained in greater detail in the FAQs.

And if you mix varieties in the same tray you will get all sorts of germination times. There are many discussions here about how to cope with this problem. Once the first ones germinate they must be removed from the tray and uncovered while the rest remain covered.

Once my plants look strong enough I'll harden them off. I will not pull them out of the pots until it's time to put them in the actual garden. That will be their only transplanting moment.

Very few things can grow in the 72 cell flat to garden size without getting root bound. They also tend to get long and leggy with weak stems and so need to be deeply transplanted at least once.

Most every experienced seed grower transplants the plants at least once to larger containers - larger cell packs, foam cups with holes in them, small 3 or 4" pots, etc. Here in the greenhouse plants are transplanted 2x before they are ready for garden planting. How to do this is discussed in detail in the FAQ "OK, my seedlings are growing,now what do I do?"

Plants that have been transplanted at least once have much stronger toot systems as a result and will tolerate hardening off and garden transplanting much better - that's why pro growers do the interim transplanting.

Good luck with your plants.

Dave
kistler
Original Author
15 years ago
It takes time to help a newbie and I really appreciate your sharing your knowledge. It's a huge help. Yeah, it turns out the "potting soil" I used is Ferry-Morse Seed Starter Mix. I mixed that with vermiculite 50/50. A nurseryman here told me to mix potting soil with some perlite half and half with vermiculite and the Ferry-Morse seemed to fit the bill. If I've overdone the vermiculite, then oh wow, I've already made the mistake.

I'm glad you shared about planting more than one seed. I'll go back and add more tomorrow when I get my hands back in the soil. :) Today I only planted one in each pot. I thought they looked rather lonely. *grin*

Dave, what you're talking about with the foam cups with holes in them, small 3 or 4" pots - can I just get foam coffee cups and use those? They're good and cheap.

I'm watering from the bottom and it seems to be taking a while for the soil mix to wick the moisture up to seed level. I'll check again in the morning.

What you've said makes good sense. Understanding the "why" of things helps. Thanks.
Karen Pease
15 years ago
Well, how many seeds to plant in each is a matter of personal preference. If you plant more, you may want to have some spare trays around for "thinning out" into. In general, I do multiple of tiny seeds, or seeds I'm uncertain about, but often, with seeds that I know have very high germination rates (like tomatoes, for example), I'll just put one. I've had enough experience with putting three tomato seeds in each planter pot and ending up with three times as many tomatoes as I have room for that I don't care to repeat ;)
kistler
Original Author
15 years ago
Thanks Karenrei. That's good to know and will save me some trouble.

At one of the links Dave shared it says:

"Sowing seeds: Fill containers,allowing an inch or so from the top for easier watering, and moisten well. Allow excess water to drain, medium should be moist,not soggy. Press the medium down lightly to eliminate air pockets. "

It sounds like I should thoroughly wet the soil prior to planting my seeds. I bet that's why my soil isn't wicking from the bottom very well yet. It just needs a good soaking first. I pulled this together in a hurry which is why I'm missing important details I think. We're building the square foot garden planters and doing everything at once. Not recommended! :)
digdirt2
15 years ago
Sure the 8 oz. foam coffee cups works very well. Just be sure to poke holes in the bottoms of them and a couple near the bottom on the sides too for drainage. And then just write the name right on the cup.

If you needed bigger containers later on for some reason you can go to the 12 or 16 oz. plastic drink cups. Some even use the paper Dixie bathroom cups for small things and there is always newspaper pots too.

On the multiple seeds in each cell bit - any extras that do sprout can either be transplanted out or just snipped off with small scissors if you don't want the extras.

I don't think adding the extra vermiculite will hurt anything. Just extra $$. We grow many things in the greenhouse in straight vermiculite. But you will have to feed them once they develop true leaves. No nutrients in the FM mix or in the vermiculite. Use a 1/4 strength diluted mix of any good liquid fert.

And yes, definitely wet your soil well before planting. ;)

Dave
hsernulka
15 years ago
Thanks digdirt for the info on the FAQ section. For as long as I have been on these forums, I never knew there was a FAQ section offered for each. Learn something new everyday from y'all! Thanks again!

Confused about proper starting containers for indoor seedlings

Comments (12)

digdirt2

Karen Pease

Related Discussions

janbanks

kistler
Original Author

hatchjon

Karen Pease

digdirt2

kistler
Original Author

Karen Pease

kistler
Original Author

digdirt2

hsernulka

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Confused about proper starting containers for indoor seedlings

Comments (12)

Related Discussions

kistlerOriginal Author

kistlerOriginal Author

kistlerOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

kistler
Original Author

kistler
Original Author

kistler
Original Author