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Potting up seedlings

Posted by greenlott Mississippi Delta (My Page) on
Mon, Mar 3, 14 at 13:12

I have seedlings in small baking tins. They were planted on Feb. 15th and now have their first true leaves. Each baking tin has about 15 seedlings. They are ready to be transplanted to growing pots but the weather is really awful here. I normally pot them up and put in a greenhouse but am afraid that the cold weather will hurt them because I have no heat in the greenhouse. How long can I keep the seedlings in the baking tins before potting up without hurting the plants?


Follow-Up Postings:

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RE: Potting up seedlings

Is there no intermediate solution, one that gets them out of the over-crowded tins where the roots will quickly become entangled and matted and into individual containers but that can remain in the house where it is warm?

Many go from seedling trays into individual plastic cups of various sizes and then only later once the weather improves and AFTER they are hardened off - out to the greenhouse.

Dave


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RE: Potting up seedlings

I have too many to keep in the house in individual cups. 15 baking tins with 15 seedlings in each tin. My goal is to have 15 plants of 15 different tomatoes.


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RE: Potting up seedlings

So you planted 225 seeds to get 15 tomato plants? What did you plan to do with all the rest?

If 15 plants is all you need then just sacrifice/scissor snip off all the extras in each tin. That way the ones you want can stay in the tins longer alone and do ok for awhile longer.

Only other alternative is to heat the greenhouse but even then they would still have to be hardened off first. Indoors out to a greenhouse is a BIG environmental change even if it is heated.

Dave


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RE: Potting up seedlings

I would go ahead and pot up a few of each and move them to the greenhouse. I know it's a pain in the rear because I have done it but you can bring them in at night and put them out the next morning and so on until the night temps stay 45-50 degrees. Just looking at the forecast down there it looks like temps in the mid 60's during the day for this week and it will probably be warmer from there. I think it's worth the risk from getting stunted from the competition and or leggy from lack of light depending on your set up.


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RE: Potting up seedlings

Put them in the greenhouse so they can begin to get acclimated to the cool nights and warm days, be sure to open the greenhouse a little during the day to let in a breeze and if it gets too hot put a shade cloth inside the greenhouse just under the plastic. In a cold night of possible frost i use a piece of wire mesh to go over my tomatoes and cover with a frost blanket on top.I grow tomato plants in my greenhouse with no heat during the winter I just cover them very good at night through mid 20's 30's so it can be done. good luck!


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RE: Potting up seedlings

You might try setting up a bit of a mini cold frame inside your green house until it warms up. You could put some plastic bottles full of water in with the seedlings to warm up in the daytime and release their heat at night.

Having said that, if your daytime temps are in the 60's, I can't imagine your nights being cold enough to hurt them?


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RE: Potting up seedlings

Thanks all. I have decided to wait until this week end to pot up. The forecast looks as if I can safely keep them at night above 40 degrees in the greenhouse.


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RE: Potting up seedlings

I just up sized the pots for a bunch of seedling. They were in starter pods. They grew too tall so I was very careful in tearing away the Jiffy starter trays, and repotted them into 4 inch Jiffy pots. Though I have them on a bench with lights. I put them out in the shade on decent days to let them get a little breeze to move them. As you can see from the picture I am starting to run out of room on my reloading bench. Though I have the trays to put the pots in to move them. The garden center at Home Depot gives them to me if I ask for them.

Once the weather stays to where night time lows are above 50 for two straight weeks I will harden them, then plant them.


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RE: Potting up seedlings

At what stage should I start hardening off my plants and leaving them out in the sun it's around the 90s to 100s here .. They are starting to our grow there box will post some photos later


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RE: Potting up seedlings

Here's the pictures


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RE: Potting up seedlings

Another


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RE: Potting up seedlings

They look nice and healthy, I'd start hardening them off ASAP (where are you that it's 100 already? Is it supposed to get any cooler soon?). But put them in opaque cups or pots - it's not good for the roots to be exposed to light.


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RE: Potting up seedlings

I'm in Perth Australia so pretty warm here.. It will probably stay around that for another month .. Sounds good they are starting to crowd my peppers because they are so much bigger than them. Got a couple of cooler days to come but will put them out in the afternoons and mornings .. How long should they be out in the sun for? Thanks
Jarryd


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RE: Potting up seedlings

Start slowly, don't put them in direct sun at first, move them inside as soon as they start to wilt. Build up the time gradually until they're able to stand being out in indirect sun, then you can move them into early morning or late afternoon direct sun for a short time. Best to start this process on a day (or few days in a row better) when you don't have to work and can keep an eye on them. It's likely to take 10-14 days depending on weather.

They look like nice sturdy stems but also want to provide a bit of a wind break at first - if only to prevent the cups from tipping over.

Just do a search for "hardening off" - I call it "the tomato shuffle" LOL b/c there's a lot of back and forth, esp. if the weather turns hot or cold or very sunny or cloudy and rainy - some years it's taken 3 weeks to harden off b/c Mother Nature wasn't on the same schedule that I was!


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RE: Potting up seedlings

Greenlott & Centexan, the main problem I hear (or see) is that you want to take a big leap from closely planted seedlings to larger pots or cups. Pot-up gradually and space won't be the extreme issue you imagine. I always transplant first to 48 cell 1020 trays from seeding 1020 trays, a 5-6 fold increase that for 225 seedlings requires only 5 trays- still very manageable indoors (I currently have 23 trays of only tomatoes currently under lights).

If you go to the garden centers for used trays or packs (not visible from pictures) just be sure to dip them in a bleach solution to sterilize before using. Those same 6-packs and trays can be reused 20-30 times and are meant to be plant friendly, unlike solo cups or even peat pots. Furthermore Centexan, one plant per peat pot if you use them.


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RE: Potting up seedlings

Should I put my plants in the previous pictures into larger pots will that help there growth? Also one of my cups fell over and kinked one of the main leaf stems what should I do it wants to just hang now?


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If a person pots up from seedlings gradually all the way up to a two gallon container, setting the plant deeper each time will the transplant shock still be as evident as a 12" plant in a 6" pot? or will it be more? Is it the lack of roots on a larger plant the reason transplanting set back is more dramatic?


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RE: Potting up seedlings

Should I put my plants in the previous pictures into larger pots will that help there growth? Also one of my cups fell over and kinked one of the main leaf stems what should I do it wants to just hang now?

You could - it would be helpful to them to get out of those clear cups. But given their size already they really need to be planted in their final growing place by now, weather permitting. So it depends on how long it will be before you can get them into the garden?

Just pinch off the broken part at the break. It causes no problems.

If a person pots up from seedlings gradually all the way up to a two gallon container, setting the plant deeper each time will the transplant shock still be as evident as a 12" plant in a 6" pot? or will it be more?

It will be more. The larger the plant, the greater its over-all needs, and the less it tolerates transplanting and adjustment to new environments. It isn't "lack" of roots. It is total plant adjustment. Bigger/older the plant the greater the shock, the greater the care required, and lower the survival rate..

The ideal transplant size is 6-8" tall with root development proportionate to that size. Of course there is some marginal room in that standard but it shouldn't be pushed any more than is absolutely necessary.

Dave


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RE: Potting up seedlings

jarry - Just pot those plants into opaque pots or cups (with holes drilled in the bottom), soil-less mix for now, not sure what you mean by "main leaf stem" but you can take off all but the top couple pairs of leaves and pot them deeper than they are now, if stem is only kinked it will be fine. Roots will develop all along the stem underground (in fact, sometimes you will see white bumps above ground if it's really moist, they're called adventitious roots).

Not sure what your season is, sounds like you are shooting for harvest in Aug/Sept if plants are that big now - when did you start the seed? But your seasons are reverse of what we have here in N. America, it's hot there now but when is your first frost? What varieties are you growing and what are the DTMs?

I'm hoping you can take the next few weeks/month while it's hot to harden these off, but still have 3 months or so of nice weather to get them to harvest.

stimey - being rootbound doesn't help, but the reason you try to transplant around 8 weeks is that if the plant is much older/bigger, it starts to go into reproductive phase (getting flowers and fruit), not vegetative (growing) phase, it's kind of like a tween or teenager maturing and then you're trying to get him/her to grow taller when the kid has already entered puberty. Doesn't work (esp. with girls - though with tomato plants it helps to nip the flowers off and plant deeper to get roots along the stem).


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I start my seed about 5 weeks ago don't know if that's quick or not? I won't get a frost it won't get cold enough over the winter, days won't get colder than 20 degrees Celsius and not often under 10 at night. I'm growing Roma tomatoes I don't really know I got them from the local shop was an after thought to do with my peppers but glad I did. What's DTM's?


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RE: Potting up seedlings

You are in PERTH, West Australia, subtropic ? And now it is the end of your summer ?
So , why can't you grow them outside, either in ground or in pots ?. Is that because it is still TOO HOT outside ?

Anyway, you can harden them off in shade/partial sun then introduce them to more sun. Your situation if foreign to most of use here in the US. Maybe, some gardeners in West Texas and Florida might have your problem, 6 months from now.


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RE: Potting up seedlings

Those are big for 5 weeks, pot them up in opaque pots and harden them off in the shade, gradually introducing indirect sun, until the real heat is over (I'm assuming they're in the house in about 20-24 degrees C right now?). Maybe some shade cloth after you get them transplanted?

You may want to check out the Florida gardens, or start a new thread on this forum looking for help from Southern (US or hemisphere) tomato growers.


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RE: Potting up seedlings

It's really hot at the moment like 35-40 degrees celsius so as soon as you put them outside they wilt. Iv hAd them outside in a box since seeding them and in indirect for awhile just opening the lid to the box so trying to harden then off at the moment in the sun. I think ill grow them in pots as i don't have much garden. What size pot you recommend?


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RE: Potting up seedlings

Thai is ok for plants to wilt a little bit. Even inground established plants do witl in a bright warm sunny day. With the seedlings, you do it a couple of hours a day at first and keep extending it. That is what HARDENING OFF IS. In a way, it is like humans getting a tan. You don't lay down on the sands for hours the first day ; Do it a bit at a time and use some sun screen lotion. Of, course the plants are tougher than we are.


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RE: Potting up seedlings

Put them out in the evening when it's still warm but not sunny if they're wilting. Yes, a little bit of wilting will occur but unlike humans (who may burn but then peel and recover from sunburn), a serious case of sunscald can kill a pepper or tomato seedling. Build up slowly, first getting used to heat and then sun.

See above for pot sizes.


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