So I’ve had two rounds of trying to plant seedlings for a rooftop garden. Last year I had good success with buying started plants and keeping them in pots but this year I wanted to try to start with seeds. Having good success getting them sprouted but most have been dying off around the time their first true leaves start growing and I can’t figure out why. The first round that I killed off I think I overwatered/soil not draining good enough (which started a fungus gnat problem). For the second round I mixed up the soil with more bark and rocks, checked the soil in a couple spots before watering to make sure, but they’re still dying! So far my tomatoes and bell pepper seedlings have stayed strong, but my pumpkin, zucchini and watermelon (didn’t even make it to fully sprout this time) are just struggling. The seedling stems just start going limp, droopy, shrink at the end in the soil and then the leaves start dying. They’re near a north facing window and have a grow light to help support maybe 2-3ft above them. The sweet grass seeds that I planted at the same time for my dogs that are getting the same treatment as the others are having no issues growing at all. The seedlings were watered yesterday and soil was dry beforehand. Soil today is dry on top but underneath still has some moisture but I would say it’s less than damp but is not dry. I included pictures of how they looked last week on 5/9 and pictures of them today 🙁 I’m only planning on actually growing one of them in the pot, planned on keeping the best looking one and giving out the rest once they’re ready to go upstairs to the roof. But I know these pots have been able to support these plants before.
by tuna_salad1
19 Comments
I can’t be sure but I would assume they’re not getting enough light. Some of those long stems also seems like they trying to reach for the light. I had similar issue and it only resolved after I increased lighting. I know, I know, it’s really frustrating. If you could get them closer to the window or place your growing light about 0,5 ft above them.
Second tip is that you let them grow in a smaller container first and after that transplant to the bigger ones.
Good luck.
Edit: If you want them more compact so they’d fit under the lamp, you can seed them in those containers and separate them when they have couple of leaves.
The “shrink at the end in the soil” symptom is called damping off. It’s a fungus that gets in there and kills the seedling. What it means is that the top of the soil is too wet, and the seedlings are too weak to resist.
I recommend the following to help your setup:
1. You need a lot more light. I have my seedlings under 5 Barrina T5 lights (2 feet long), about 6″ above the seedlings, spaced about 3″ apart. I go for 200 – 300 ppfd, and run them for 16 hours per day (though 12 is probably fine too).
2. Use smaller containers. Start in small cubes or pots (2-3″ max), then up-pot after they get that 1st set of leaves. The soil in your larger pots will stay wet too long for those little seedlings.
3. Add a small fan. You don’t need much airflow, but a small fan run on a timer (15 minutes / hour or so) will help dry the top of the soil out, reducing the chance of damping off, and help them grow stronger stems so when you set them out, they’re more ready for the outdoors.
they look like they‘re either etiolated (not enough light) or you didn‘t bury the seeds deep enough.
You’re growing them in dust. Start over. Water the poor things!!! Bottom soaking, and lots of light, grow lights down close if possible. Keep soil level up even with pot edge for plenty of air circulation. Run a fan in the room (not directly aimed at them).
They need more sun I think. See how this stem
Is really long and thin?
Get yourself a humidity tray with a transparent cover and a heat mat. Put the tray in a sunny spot or under grow lights. Soak the heck out of your seedlings and put them in the tray, cover it up, and check in them periodically. Do not let them dry out. If you don’t feel like getting a tray, a takeout container will do in a pinch lol.
Once they’re much bigger you can pop them in a slightly larger container and take things from there.
As much as I love this sub, I think you’d get muuuuuuuuch more helpful advice for advice on r/gardening, r/vegetablegardening, or probs even a homesteading subreddit in this case since you’re growing from seed.
use a good seed starting mix like ProMix
These are absolutely not getting sufficient light exposure, which is why they’re stretched. They require a lot of direct sun. The composition of the soil is fine. A finer substrate is traditionally used for starting seeds anyhow.
When I would start my seedlings I would use a heat mat until germination then a grow box. I simply got a plastic tote and lined it with aluminum foil. I cut a hole in the top for the light to fit through and put them on a cycle that was specific for the type of plant. You want the light a few inches from the plant but not so close that you fry the leaves. This method also works as a green house because it traps the moisture inside. I started alllll types of fruit and vegetables this was and I never had an issue. The heat mat speeds up germination but the grow light was crucial for me as I was on a covered north facing balcony.
Another thing is that the pot is too big. When you water, the seedling can’t get to the water.
They need to be moist. You can put a plate of water under the pot.
A fast trick to save them is to take them out and plant them deeper to the hight of the leaves. Theyre growing too high rn. The soil is wayy to dry but DO NOT overwater them. Put a plastic bag over them and isolate them completely from air after your first watering, then wait for maybe 2-3 days. The soil will water itself with the plastic bag, which will also make them grow faster (humidity). Give them air sometimes. Also, they need light but be careful with direct sun since it can burn them fast. Give them maybe 15-30 minutes of direct sun when you can, or growth light for 12 hours a day depending on how fast you want them to grow. Or place them next to a window. But not too much light or they will burn, fast.
A fast trick to save them is to take them out and plant them deeper to the hight of the leaves. Theyre growing too high rn. The soil is wayy to dry but DO NOT overwater them. Put a plastic bag over them and isolate them completely from air after your first watering, then wait for maybe 2-3 days. The soil will water itself with the plastic bag, which will also make them grow faster (humidity). Give them air sometimes. Also, they need light but be careful with direct sun since it can burn them fast. Give them maybe 15-30 minutes of direct sun when you can, or growth light for 12 hours a day depending on how fast you want them to grow. Or place them next to a window. But not too much light or they will burn, fast.
A fast trick to save them is to take them out and plant them deeper to the hight of the leaves. Theyre growing too high rn. The soil is wayy to dry but DO NOT overwater them. Put a plastic bag over them and isolate them completely from air after your first watering, then wait for maybe 2-3 days. The soil will water itself with the plastic bag, which will also make them grow faster (humidity). Give them air sometimes. Also, they need light but be careful with direct sun since it can burn them fast. Give them maybe 15-30 minutes of direct sun when you can, or growth light for 12 hours a day depending on how fast you want them to grow. Or place them next to a window. But not too much light or they will burn, fast.
A fast trick to save them is to take them out and plant them deeper to the hight of the leaves in small pots. Theyre growing too high rn. The soil is wayy to dry but DO NOT overwater them. Put a plastic bag over them and isolate them completely from air after your first watering, then wait for maybe 2-3 days. The soil will water itself with the plastic bag, which will also make them grow faster (humidity). Give them air sometimes. Also, they need light but be careful with direct sun since it can burn them fast. Give them maybe 15-30 minutes of direct sun when you can, or growth light for 12 hours a day depending on how fast you want them to grow. Or place them next to a window. But not too much light or they will burn, fast.
Need water. You can’t just lightly water seedlings as seen in the photos with only some of the middle soil even being moist.
The soil needs to stay evenly wet so some saran wrap or a clear dome over the top until the seedlings become more robust is needed.
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That’s not how you start seedlings. Look for a seed starting tray.
On top of what everyone else said, those containers look huge for seedlings. Start them in something much smaller.