What I have here is a pumpkin plant and you can see the top leaves here are green and healthy, but when I spin it around you can see the lower leaves here are starting to yellow. I get lots of emails about yellowing leaves. Lower leaves like this that are yellowing are fine. What this might mean is it’s not getting enough light and that’s normal. As the plant grows up this is going to happen. Also notice these first little leaves here. These cotyledons are also yellow so this could mean that you need a little more nitrogen. Many times it means the plant is sitting in water too much. Another problem that could cause yellowing is if you’re leaving the lights on for 24 hours and not shutting them off, this can lead to excess yellowing. So when you see this it’s a minor problem. When it’s down low like this if all your leaves start to yellow the top leaves like this. You see yellowing most likely means you have a nitrogen deficiency. Yellow leaves aren’t the end of the world. It just means something has to happen. I think one of the problems with this, as you can see, the roots here for this plant is quite large for this small pot I put them in. This cups here are so you could see the roots. You can see they’re starting to grow round down here. So I think that this plants’ little root found the small container and as it gets bigger it is getting some yellowing. So what I’m going to do is put this in a bigger container. This has been under a fluorescent light. I’m going to put this under high pressure sodium light then eventually plant this outside. I think that’s going to take care of the problem. So yellowing leaves are not the end of the world. Oftentimes it means you’re over watering your plants or that they’re not getting enough light on the lower leaves. Yellowing is a normal thing. Don’t worry about it if your plant is flowering as that’s also a normal part of flowering.