📌 Quick Summary (TL;DR): Seedling Growth Spurts & “Praying” Leaves
- 🌡️ Optimal Temperatures: Growers discuss keeping indoor seedlings at 64-72°F (18-22°C) during the day and dropping to 59-61°F (15-16°C) at night to prevent them from getting leggy.
- 🌱 The “Wall” Growth Spurt: Seedlings often sit seemingly stagnant for a while. Growers note that intense top growth usually kicks in right after the roots hit the side of the cell or pot.
- 🪴 Why Do Leaves Point Up? (“Praying Leaves”): When seedling leaves point straight up toward the light, growers debate the cause. Common theories include a need for water, a mild phosphorus deficiency, or even the phototropic and gravitational pull of a waxing moon phase!
Aleksan9ra (Ludmila) wrote:
My tomatoes. Here on the windowsill, I have 6 plug trays with 10 plants each. I’ll only be selecting the best 40.
If you sowed them on February 23-24, they are about 21 or 22 days old now?
Not a huge difference compared to my test batch. I’m testing out growing temps of 64-72°F (18-22°C) during the day and dropping to 59-61°F (15-16°C) at night. I specifically took a photo of Burkovskiy Ranniy (on the edges) and German Red Strawberry in the center. They look almost identical to yours, but mine are only 15 days old (the sprouts broke the surface on the 8th). I run grow lights for up to 14 hours on sunny days, and leave them on all day when it’s overcast.
Valtwelve (Valery) wrote:
Not a huge difference compared to my test batch…
Yeah, looks similar. Mine are older, of course. But they usually just sit there doing nothing for a while, and now that we have more daylight and the sun is getting warmer, you can really see them take off and start growing.
Aleksan9ra (Ludmila) wrote:
But they usually just sit there doing nothing for a while, and now that we have more daylight… you can really see them take off.
It seems like they really start growing fast right after the roots hit the side of the cell wall. Here is a photo of Rozovyi Myod (Pink Honey) at 10 days old, and then 3 days later:
By the way, when seedlings point their leaves straight up like that—does it mean they are asking for water? Some sources say they need water, while a popular gardening channel on YouTube claims they are supposedly asking for phosphorus. In this case, neither would hurt, but still, what’s the real reason?
Valtwelve (Valery) wrote:
By the way, when seedlings point their leaves straight up like that—does it mean they are asking for water?
Valery, as far as I know, the explanation for this phenomenon is actually very simple—it’s the influence of the moon. We are currently in a waxing moon phase. The moonlight increases every day, the moon’s gravitational pull gets stronger, and this leads to intense upward leaf growth. That is exactly what we are observing right now.
👨🔬 Editor’s Botanical Note: While moon phases and phosphorus deficiencies are popular gardening theories, the real reason tomato seedlings point their leaves straight up (often called “praying”) is actually a sign of excellent health!
This upward movement is driven by high turgor pressure (meaning they are perfectly hydrated). Toward the evening, plants naturally raise their leaves in a process called nyctinasty (plant sleep) to conserve heat and moisture. If they do it during the middle of the day, they are simply angling their leaves to avoid absorbing too much intense light from the grow lamps. Your seedlings are happy and growing vigorously!
