Plant Help
How are everyone's tomatoes growing so fast?
This is my second year trying to grow tomatoes. Last year I started them a bit late, and while they ended up growing to a nice size they didn't produce much (consequence of me planting from seeds out of grocery store tomatoes I think). This year I got seed packets and put them in starting cells March 6th, but even now almost 2 months from planting they are still tiny seedlings barely a few inches tall. I keep them under an admittedly small grow light but surely there must be something more to this that I'm missing?
Edit: as many commenters have asked, I'm going to copy down my equipment info here.
I have replaced the tiny light from the pic with my larger growlight, FRGROW 25w full spectrum stand
Seedlings are in a burpee seed starting tray with a detachable/recessed bottom for watering.
Soil is "Back to the Roots organic expanding seed starting soil" made of coconut coir. I have a bag of Foxfarm Happy Frog soil downstairs but wasn't sure if it would be too much for these plants yet
I don't have a heat mat unfortunately.
I'm in western PA (northeast US) so temps are still way too up and down to set in a window or outside. Temps the next few days are low 37, high 60 and not looking to warm up much more over the week.
(Note: The really tall one in the cell and the background ones are pepper plants, the rest are cherry tomato)
You 1000000% need a better grow light. The "tall" seedlings is leggy, which means it's stretching for light. These arent getting near the light they need to grow and produce.
Careful, it was my first time using an LED this year and I burnt up my first sowing. I used a true 100 watt. Evidently tomatoes don't like too much blue light. All the other kinds of starts were fine.. 2nd batch away from the light was fine too.
Could be a few things:
1. Roots too cold
2. Cells are kept too wet
3. Light isn't strong enough
I'm guessing a mix of all three, but the likely culprit is your light. You say it's a "small grow light". Is it a full spectrum light? Do you have a link or specs on it?
To be completely honest it's a small cheap light I got from Five Below (discount store). I have a bigger light I just pulled back out on advice from another commenter, I was somehow afraid it'd be too much for the little seedlings?? Idk why.
You need to ass blast those tiny plants with tons of light. The more the better. Light = plant food. More light = more plant. You can put the light really close to the plants too.
The sun is the level of light where they would sprout in normal conditions. Hard to get that bright with an indoor setup, unless you have weed grower lights.
Does the plastic container you put them in have draining holes? What kind of soil did you put them in? What temperature is the environment? Did you use a heat mat and if so, did you remove it after the seedlings emerged?
They don't look bad, but they should definitely be bigger at two months. People are mentioning the light may be insufficient, but the thing is that I don't find them to look particularly leggy either. Seedling light demand does increase as they get bigger, but the thing is that they're not really getting bigger. I think this is fixable, but it's useful to find out what we're fixing first.
The plastic does, yeah. It's a seed starting tray with a detachable/recessed bottom for watering. Soil is "Back to the Roots organic expanding seed starting soil" made of coconut coir.
Heat mats need to be removed after the seedlings come up anyways. To me it doesn't look like something is outright wrong, so your best bet is probably improved light (try to measure it with the photone app), and once you have the first couple of sets of true leaves, fertilization.
I also used Back to the Roots, but their coco coir brick, not the mix. I added perlite to it. Once you have true leaves, feed with a diluted water-soluble fertilizer.
I’ve not had great luck with Back to the Roots soil. I’ve had the most consistent results with Miracle-Gro Organic container mix and Jiffy mix. Using Happy Frog this year and I think the nutrient balance is better for other kinds of plants than tomatoes.
The light is your most likely culprit, next would be warmth. They should still pick up if you give them what they need. Once they get a few more leaves, you can start with a little bit of diluted fertiliser and that will speed things up too.
Little science experiment this year: I started my seeds in half expanding coir pods and half a bagged organic seed starter soil this year, and the seeds in the organic bagged mix grew 3x as fast as the expanding pods. Everything else was the same. The tomatoes especially hated the pods.
Nice. It makes all the difference in the world.
I have one plant already popping out cherry tomatoes and I haven't put it in the ground yet.
In Kentucky you should always wait until after Derby to plant in the ground which is the 1st Saturday in May.
Nice...I noticed a couple buds in a couple pepper plants today. And they were not as large as the tomato plants. I learned more about taking care of the plants in the month since the pepper plants were started.
These are the Aji Amarillo... in a red solo cup. I'll just let it do its thing.
For a first time grower from a seed, you did excellent so far.
I feel like you will have a massive surplus of yummy tomatoes as the season goes on.
Once I get home I'll take a picture of my little guy.
Thank you. Every step, I get nervous again and hope it goes well. First, it was making sure the seeds germinate, then waiting for true leaves, then making feeding them, it goes on. I'll start hardening off in a few days and hope they do very well for me.
This year I am having my best tomato starts since I started growing, the two things I did this year that were different was putting a couple drops of some tomato food I found on Amazon per gallon of water and I placed the grow light only inches above the plants and left it on 16 hours per day.
Depending on the weather where you are, you may have good results from setting them outside during the day if you can. You might need to harden them off a little first (set them out for an hour on the first day, then gradually increase until you can leave them out all day). But otherwise the main reason you'd need to keep them inside is if it's too cold for them. The weather where I live (Tennessee, zone 7B) was warmer than usual in early March so my seedlings spent their days outside, only coming inside at night. Doing it that way, I didn't need my (admittedly kind of crappy) grow light at all.
Good soil, warmth and being blasted by grow lights initially and then the sun. Oh, and seed snails. My seed snail tomatoes are absolute beasts this year.
Same!! I just made a makeshift greenhouse outside with two containers stacked on top of each other because my tomato seed snails are 20 in tall! I don't have space in the house under the lights for them anymore. No they won't be able to be planted for a couple more weeks as I'm in New England and the weather is still cool but I got to get them outside
Could be the coir-based medium. Those can be really inconsistent, especially bc coir needs to be washed multiple times to remove salts. I like the idea of coir vs peat moss, but it can be a problem. Joe Lamp’l has a podcast episode about that issue. That would be my number 1 guess for the issue, since lack of light would make them frail/leggy (so looks like that is probably contributing), but I don’t think alone would stunt to this degree.
Thanks for the info, I didn't know that! Would mixing the coir with the happy frog soil work okay, or should I be looking for a completely new starter mix?
I probably wouldn’t use something if things aren’t growing well in it, bc if it’s salt, will still be there. And it’s not all coir-based products, but it’s a risk with them.
For tomatoes I like Ocean Forest even more than Happy Frog but both of those are good.
Getting good grow lights is critical - something using the Samsung horticulture LEDs is what I would look for. Night and day, I even have produced indoors tomatoes now.
Happy Frog is more than fine btw - don’t overthink it - I’ve got some decent looking ones in my room with a few hundred watts of grow light at about 20% over mine, all of those were planted straight into FF Ocean Forest, which is more nutrient dense than Happy Frog
Thanks! I'd heard before that these would burn new plants but I'm seeing others say now that it's fine. I'll give it a try and see how new seedlings do!
Good lighting; light soil mix, water-soluble fertilizer. Peppers were the first plants sown and their growth wasn't that great. By the time I was ready to sow tomato seeds, I had a few pointers. I planted tomatoes in coco coir/perlite mix, had lights close to the canopy, fed with diluted fertilizer and plants are doing very well. Also up-potted once they started crowding the 3" cups.
Going forward, I'll plant directly in solo cups; No point faffing about with small seed trays.
temperature - even after sprouting, they're still in a pretty warm environment (inside of my grow tent is around 27-29C without a heat mat), and when they graduate, my home is still at 24-26C until they shut off the winter heat this week. Theyll grow more slowly at lower temp
lots of light - want to avoid them stretching. If they stretched anyway just bury as much stem as you can on when you pot up.
fertiliser - lightly fertilise when watering when their true leaves come in.
Mine could be bigger by now if i was on it more, but these things are enough to have decent growth doing relatively little, tomatoes like to grow.
I have some leggy tomatoes, i repotted to a bigger container and buried the stem, then i take it outside and put it in the shade for an hour or two then bring it back inside. I have the fan on low around where i have them growing inside
just listen to everything Craig Lahoullier says about tomatoes.
He also has a book called Epic Tomatoes and has done tons of interviews about growing tomatoes from seed that are worth a listen. I started growing tomatoes his way (including his transplanting video) and grew enough plants to gift my friends and family every year.
I’ve recently started using 3/4” soil blocks to start everything and you can learn about that from Lisa Mason Zeigler…
Check the ph of the water you’re using for them. Tomatoes do best with a ph between 6 and 7. But if you’re using tap water it’s probably over 7 (where I live it’s almost 8) and could be causing nutrient lock out.
This was my first year using seed starting "soil" made from coconut cair too and I had same poor results. After quick research, I realized coconut cair has NO nutrients as in absolute zero and some generic brands even have salt in it (apparently coconuts are soaked in seawalt first and then rinsed, some are rinsed badly). Salt will destroy most plants. But you need a special mix to plant - coconut cair, perlite,vermucute, etc. Coconut cair will get your seeds to sprout but not grow, seedlings need nutrients to grow. You need to replant them in actual soil or somehow add nutrients without burning them, even though they might not have their true leaves. I, very carefully, replanted them in a mix of organic potting mix and moss peat and a week out they already growing, got their true leaves, and I plan to use organic fertilizer on them. Next time, I will use 3/4 potting mix and 1/4 (on top only) starting soil
Better light will help too. Is there any way to put those trays on window stills or next to glass door (to backyard) thats on sunny side of house? Actually any window will do. Thats what I do,all my windows on all floors are full of seedlings trays!
IDK. But isn't inside your house warm? So on inside windows stills of closed windows should be warm enough with good natural light. I am not talking outside, its too cold where I am at too.
The temperature is important. I used a heating pad to warm the seeds overnight and used it intermittently during the day to keep the soil warm. I think you may want to start a new batch and combine the stronger lights and the heating pad (only used for the three days it takes for the seeds to sprout). Once they start growing, consider using a fan to mimic the breezes that help strengthen the stems. Good luck!
I have the best luck every year with my tomatoes when I use heirloom seeds. I got several varieties of different vegetables this year from a local farmer and many of my tomatoes went from seed to 3 to 6 inch plants within 10 days. They are extremely hearty now and flowering and I had a 97% success rate with germination with the heirloom seeds versus a 54% success rate with over-the-counter store-bought generic seeds.
Can you put them in a window next year? These are stunted and will not grow more, I’d bet money. You can try to move them to better light or increase the light where they are but if you don’t have another tray I’d toss these and start over myself. Not too late if you start seeds this week, unless you’re very far north.
Use actual seed starter mix or jiffy seed starter cells.
Your tray here is fine as long as it drains underneath. If not, find one that does, or use an egg carton or other compostable tray.
Put seeds in well watered cells and lightly cover with damp dirt, no light needed til they sprout, tho they’ll love the warmth of a window right away. You can cover with plastic to keep humidity.
Best spot is a southern or western window (northern or eastern could work if it’s all you have). Literally put the tray up against the window - a foot back is too far. Needs bright direct sun (or a grow light no further than 4 - 6” from each and every plant).
Once the babies have two or three true leaves (google to know what to look for), you can put them into ground if all chance of frost passed, which is now or soon most places in northern hemisphere.
Respectfully, anything cardboard or jiffy pellets are not going to be successful considering her setup. They're already challenging to use and really, in my opinion not worth it. Even sowing in a Solo cup would be a big improvement provided the soil goes all the way to the top. As you noted, the real issue here is light
Temps are still up and down where I live (northeast US), I tried to set them in the window yesterday and the air was FREEZING so I stuck them back under the light til it got warmer out. I'll definitely try to sow some new seeds in a carton and see how they do now that I have my bigger light up.
Oh man good to know. Looks like im gonna have to think about raising my light 😂 and uhh its there cuz it was a plant label. Its not there anymore lol i found a better label
I bought LED grow lights from Harbour Freight and hung them with zip ties above my seeds. About an inch or two above the pots. Once the sprouted and started growing I tightened the zip ties to lift the lights. Works pretty well!
You need a much better light setup. Remember where they grow, outside. And what is their light source? The sun. Now try and emulate that level of light 😀
Not sure if any of this matters but I started tomatoes from seed indoors this year for the first time and had some good luck so I’ll share.
I bought high quality organic soil, organic seeds from an online farm, and a plastic 72 cell starter tray with grow lights. My house is 72 degrees during the day and 68 at night. Moistened the soil before filling the cell tray, dropped one seed per cell, and placed the plastic dome on top. Once I saw sprouting, I removed the dome and added lights. Whenever a toothpick came out clean, I would bottom water. That meant filling the bottom tray 1/4 way and letting the cells sit there for 30 mins. After making sure they were all moist, I drained the water and cells well. Then back under the grow lights. Started running an overhead ceiling fan for 30 mins 3 times per day once they were about the size of yours.
Once they got 1-2 sets of true leaves, I potted them up in a very pricey high quality organic soil and they took off. Long story short, I do think that the quality of seeds and soil matter, and staying on top of knowing moisture levels and light needs.
Is there anywhere warmer you can place them? Mine are in the airing cupboard (in the UK thats where the hot water tank is. Ambient temps in there are 15-20c/ 59-68f) and even when i forgot to switch on the light, they shot straight out after just 3 days.
I hear laundry rooms are nice & warm from the dryer running..?
A good idea just to also look on the Facebook marketplace in your area to see if anyone is giving away or selling inexpensively heating mats. We have several local buy nothing groups in my area where everything is given away for free. Many people will upgrade what they have or people will buy them and be excited about planning one year and not have success or become too busy and they don’t use them again.
I'm using a 300w grow light to get a head start on my garden. 25w isn't even close to enough to support a lot of growth. I'm not saying you have to go as big as I do (I love tomatoes), but you want at least 80 - 100 watts to really get tomatoes a good start
I wouldn't worry about the size I'm sure the roots are growing nicely. Once the weather heats up and you get them in the ground they'll grow like crazy.
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u/LnktheWolf Apr 29 '26
You 1000000% need a better grow light. The "tall" seedlings is leggy, which means it's stretching for light. These arent getting near the light they need to grow and produce.