Tomato Stunted Seedlings/Runts

[Setec Astronomy]

For the most part my tomato seedlings are doing well, most of them are 3-5" tall and have good growth, thick stems...then I have a couple that are 1.5" and 2.5" tall, and don't seem to be growing, even though I have been intently staring at them so they get the idea. I lost track if these emerged late relative to the other seedlings, and it's possible they missed a feeding if they were on the late side (I gave them a little half-strength liquid fertilizer this morning). They look a little yellowy also, and the cotyledon leaves are curled.

Are there some seedlings that are just runts? Or have I not given these enough TLC? Pay no mind to that small one further back on the right; it's a ground cherry.

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[Tormato]

In my experience, the runts almost always have very sparse roots. Overfeeding can be easily be done because they don't soak up liquid as fast as the more vigorous seedlings. I've learned to only water at the very bottom, with much less water than given to the big seedlings, in order to get those sparse roots to reach out for their moisture.

[Setec Astronomy]

Thank you, that's a little counterintuitive (for me), I'll let them dry out and then water them only lightly from the bottom. And yes, they have sparse roots, nothing coming out of the Jiffy pellet, unlike their more vigorous counterparts.

So back to my other question--are they runts because I didn't properly nurture their root development? Or are they just runts because...some seedlings are just runts?

[Tormato]

Thank you, that's a little counterintuitive (for me), I'll let them dry out and then water them only lightly from the bottom. And yes, they have sparse roots, nothing coming out of the Jiffy pellet, unlike their more vigorous counterparts.

So back to my other question--are they runts because I didn't properly nurture their root development? Or are they just runts because...some seedlings are just runts?

It was counter-intuitive for me, too. It took a few years to figure out what works, here. I used to just re-pot everything, no special order, not observing anything. When one is handling 150+ seedlings, one can easily skip what was thought to be unneeded observation. Then one year, I separated the runts from the vigorous. All seedlings were as equally watered as I could manage. When examining the seedlings root system and growing medium, the runts always came up with stunted roots and fairly soggy seed starting mix.

I know my level of incompetence when it comes to nurturing plants. I just don't believe that it is so low, that at least at times they are just runts because some seedlings are just runts.

[Setec Astronomy]

I know my level of incompetence when it comes to nurturing plants. I just don't believe that it is so low, that at least at times they are just runts because some seedlings are just runts.

Thank you...given that I had this (runt) problem last year with most if not all of my seedlings, I'm going to cautiously chalk this up to MY level of incompetence (I think this is year 3 of me growing seedlings). As I hedge I have planted backups for the two runts, even though they are weeks later, perhaps they will overtake the runts, if need be.

[Tormato]

I know my level of incompetence when it comes to nurturing plants. I just don't believe that it is so low, that at least at times they are just runts because some seedlings are just runts.

Thank you...given that I had this (runt) problem last year with most if not all of my seedlings, I'm going to cautiously chalk this up to MY level of incompetence (I think this is year 3 of me growing seedlings). As I hedge I have planted backups for the two runts, even though they are weeks later, perhaps they will overtake the runts, if need be.

I should have mentioned that it's good to have a backup plan.

Even if optimum growing conditions can be dialed in for the runts, some of them can still languish for an extraordinary amount of time. I've had seedlings started 3+ weeks after the runts, pass them by, in about the first 2 weeks of the new seedlings growth.

It sounds like you have vastly improved your growing conditions from last year. Pure accident, or modified methods of growing? And I like accidents, if I can look back on them and figure out what they were, and why they worked.

[Setec Astronomy]

It sounds like you have vastly improved your growing conditions from last year. Pure accident, or modified methods of growing? And I like accidents, if I can look back on them and figure out what they were, and why they worked.

I think I may have talked about this in another thread...or maybe I just planned to. As I said, I think this is my 3rd year growing seedlings, the first year I had troubles, not enough light and too much fertilizer (maybe--I got a lot of opinions). So last year I had too much light (really too much heat), and not enough fertilizer--I think. So this year I'm trying to get the right balance.

[Tormato]

It's a learning curve, and you seen to be advancing quickly.

After 20+ years, I'm still leaning. I may, or may not, have overdid it last year. I only grow for flavor, which means that I don't want a huge root ball soaking up heavy rains too quickly. I've been trying to restrict the root ball size, and may have finally overbalanced the plant size to the root ball size. I know that it is not a good combination with transplanting trees.

So, this past year, my plants had a load of tomatoes on the first couple of trusses, and very little after that. My plant size to root ball size may have been the problem, but other people in town said they had the same production problems.

[JRinPA]

Unless it is hybrid seed I only have a few of, I rarely plant just one seed per soil block. I'm more likely to plant five per block than one. This overseeding tends to reinforce the law of averages and quash outliers. I do get variation, but I know it is not because there were four weak seeds in one block, while I somehow planted four good seeds in another. Instead, I know the variation in germination time is due to my actions or equipment. The most common problem I get is delayed germination, from soil blocks that are sitting over a cold spot on a heat mat. The second most common is probably overheating due to a failed thermostat or a temperature probe knocked askew. When the heat is left on, those same middle blocks that start earlier, instead they die earlier.

For me, a single small one like that is probably just delayed due to lower temps at that spot. If there are 4 big sprouts and 1 actual runty one, it just gets snipped along with 3 of the big ones. I use 25% vermicompost in my block mix, so I don't add any fertilizer. I used to use "organic" blood meal/greensand/rock phosphate as well, but when they ran out I couldn't bring myself to repurchase. Mice always seem to get into the blood anyway, when I'd inevitably leave it out on the carport. I've never had to deal with the vagaries liquid fertilizer and moisture control. Just put the blocks in a tray of shallow water when they start getting light, and they wet themselves properly.

[Setec Astronomy]

Unless it is hybrid seed I only have a few of, I rarely plant just one seed per soil block. I'm more likely to plant five per block than one.

I usually plant 2-3 seeds per cell/pellet. You can see in the picture of the runts that I thinned one plant out of each, I'm presuming they were both about the same size at the time I snipped them, in this case.

[AKgardener]

I’m actually glad I saw this post I feel like I got wip lash from posting here and there but I only do it to learn and receive advise so I can apply it and be better . But my point when I tossed all my my tomatoes last night they had no root system what so ever and they have been growing for almost 6 weeks Wich tells I did something wrong. I hope the little guys make it for you .

[JRinPA]

If you have three sprouts like that corner block and the best of three is stunted, like I said, I don't believe that is the seed itself. There are bad seeds, sure, but three bad seeds in one cell is unlikely. In such a case, I'd say there was something wrong with the planting cell environment. For me that is usually the temperature, since I start most seeds in the basement on heat mats. If I get three bad ones in a cell, it is probably due to getting too hot and dried out, just as they were forming cotyledons.

I bought a big 48x20 mat this year, because I was sick of the 10x20 mats always having a cold perimeter. For my soil blocks, that is a 5x10 arrangement, so the perimeter contains 10+10+3+3= 26/50 blocks. More than half of the blocks. Early, when the basement is cold, it is often like 2 sets of seeds. The best I could do to sync up germination was to seed the perimeter and put on the mat, then wait two-three days to seed the interior blocks. That is for tomatoes. I didn't like to seed twice like that, I'd forget, etc. So this year I got a big mat, thinking it would be a lot better, more interior area. Well, turns out it is probably worse, because there are huge cold spots, in areas along the perimeter, and in lines throughout the mat. I sort of mapped it by feel, with tape, so I can sort of see where the wire must run. But it is less predictable than the small mats that are just "cold perimeter". The best I can do now is spin the trays. I do like that it is only one cord for four trays, rather than four cords.

Spinning the trays last week got me this fairly even germination. I started these the evening of Wed 6th, so 8 days old. All the cells were showing loops in 3-4 days. Are there bad seeds in there... probably some, but if so they will not make the cut.

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I have no experience with those things you are using, Jiffy pellets? Do you do the mix yourself, or is it already packed in there? With the soil blocks, my mix is 2 parts peat moss, 1 part perlite, 1 part screened vermicompost, worms included if they don't show themselves in time. Then about 1.3 parts water. It get mixed well so all the blocks are practically the same. After that it gets a lid so they stay wet through germination, and won't get watered for at least a couple weeks, then just a taste, maybe 15 seconds of sitting in a tray so the water comes an inch up the block. I don't have to do anything with liquid fertilizer, so that is one less variable for me.

[Tormato]

I’m actually glad I saw this post I feel like I got wip lash from posting here and there but I only do it to learn and receive advise so I can apply it and be better . But my point when I tossed all my my tomatoes last night they had no root system what so ever and they have been growing for almost 6 weeks Wich tells I did something wrong. I hope the little guys make it for you .

Most likely the seed starting medium was too damp. In growing for almost 6 weeks, my guess is that were not very tall. I've been there.

[Pleepleus]

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I leave the last two rows of the flat o cells empty for just the reasons you stated JR, they ends always struggle with the 10x20 mats.

[Setec Astronomy]

I have no experience with those things you are using, Jiffy pellets? Do you do the mix yourself, or is it already packed in there?

Yes, Jiffy Pellets. They come as a compressed disk that you soak with water to expand them. They are very fine peat. As I have noted, this is my third(?) year growing seedlings. The first year I used the Jiffy Pellets and then Jiffy Pots, because that is what my Dad did, and I thought that was just the way you did it. Then I came here and got a lot of negative Jiffy feedback, so last year I just did a cell tray with seed-starting mix and plastic pots. But I decided to go back to the Jiffy Pellets this year because it gave me easy flexibility to treat plants individually, like moving some out of the germination dome when the others weren't ready yet. Of course then there is the question of, as was raised by someone in another thread...do you wait until all the seeds have germinated in that cell/pellet, etc. etc.

If you have three sprouts like that corner block and the best of three is stunted, like I said, I don't believe that is the seed itself. There are bad seeds, sure, but three bad seeds in one cell is unlikely. In such a case, I'd say there was something wrong with the planting cell environment. For me that is usually the temperature, since I start most seeds in the basement on heat mats.

I leave the last two rows of the flat o cells empty for just the reasons you stated JR, they ends always struggle with the 10x20 mats.

I also use 10 x 20 mats, I don't know where the runts were on the mat.

If I get three bad ones in a cell, it is probably due to getting too hot and dried out, just as they were forming cotyledons.

Most likely the seed starting medium was too damp.

Ok--one vote for too dry, one for too wet, LOL.

In growing for almost 6 weeks, my guess is that were not very tall. I've been there.

Mine are just over 3 weeks in, since I planted the seeds. On the plus side, I have 32 other healthy tomato seedlings, where in comparison last year, pretty much my whole crop were runts. I don't know whether the runts were too hot, too cold, too dry, too wet, got taken off the heat/out of the dome too soon, too late. As Tormato suggested, right now I am drying out these two runts on a heat mat next to a tray of squash seed starts (and runt replacements); once I get them dry I will try a small amount of bottom-watering to see if I can get them back on track.

[Tormato]

Runts, on a heat mat, with a small amount of bottom watering, sounds like a combination without a lot of room for error.

[AKgardener]

Sounds my like my nightmare to I moved my racks away from the walls re did the lights hopefully things turn around when do you all fertilized and what do you start out with ? I have the alaska fish amulian and master blend our local greenhouse recommended. Really have never been to shure when to start that process

[Yak54]

Sounds my like my nightmare to I moved my racks away from the walls re did the lights hopefully things turn around when do you all fertilized and what do you start out with ? I have the alaska fish amulian and master blend our local greenhouse recommended. Really have never been to shure when to start that process

I also use Masterblend but don't give my plants any till about 3 weeks after I pot them up and only a half strength mix at that.

[bower]

Well, I am of the opinion that some runts are just... runts. Sometimes they had damaged cotyledons. Or they started out blind and only later decided to make a shoot. Variation in seed quality is inevitable.... some of them are not up to scratch.
That being said, if there's a problem with the whole batch there's something wrong with the soil, water, temperature or light.

@AKgardener I am in a cold climate like you, and I have my lights set up in the basement - in a window, in an unheated room (it just poaches some heat from the house). I hate peaty mixes, and I really struggle to come up with something that works well and has not too much peat, because it is either too wet or too dry for me, never optimal. That is because of my cool temperature. I'm using a mix of mostly commercial compost and a small bit of promix this season, but still too peaty for me, and next year I'll try the compost with just some perlite instead.
It is just way too easy to overwater with the cool temperature at my place. I can't do bottom watering at all, they would end up drowned for days afterwards...
The other thing I do to avoid overwatering, I use granular ferts - bone meal - instead of liquids. I mix a bit right into the first size of cells, and every time I pot up I mix a bigger pinch into the bottom 2/3 of the pot. That way I know they got the same amount, being I am a very sloppy waitress at best, and could never manage to give them all equal. And this way I only water the cells that are actually dry - they never seem to dry out equally either, because they don't all grow at the same rate. Anyway the bone meal is pretty good for getting healthy roots on seedlings and might help - it works for my cool temperature setup.

Also besides the 'too wet' issue for weak roots, I did some experimenting this winter with distance of lights from my greens. It made a huge difference to the growth rate if the light was too far away. And one of the things I noticed when potting up, those slower growing plants with not enough light also had very scanty roots. They weren't overwatered in this case, but the low light did a number on them.

So I think there can be several causes for seedlings to fail. I hope you have better luck next time!

[AKgardener]

I have mine in a spair room Wich was supposed to be a 3rd bedroom but double doors were installed when we got the house so it’s definitely cooler in the room even thought there are 2 floor vents you still have to keep the main door open to keep it warm enough to thrive. And of course putting certain up to maintain warmth last year everything grew great indoors despite the room this year there just not feeling it I guess haha so you try and work with Whst you got a keep on moving forward the best way you know how I love all the advice and learning so thanks for all from everyone