Minecraft agriculture goes wrong?

I play a lot of Minecraft 1.12.2 with the Mod Thaumcraft in the Minecraft Forge, but I already had the problem without mods…

And that is so if I do now, for example, a triple bed. (Picture is attached), that if I do red beet or carrot or potatoes in these three rows, which place them in the second - third, again and again (jump off, so again plop away.

How do I get that that does not happen

Although I can put something on the red marked positions, it drops again.

I would say too little light

but so btw. Your layout is generally quite ineffective

Could not be enough light.

Okey one needs light / thank you

Thank you

The answer with the light was right

The answer with the light was right

Too little light, you can see.