It SOUNDS like over-watering - possibly over-fertilizing, or both. It could also be a fungal infection if you're fond of wetting the foliage when you water - especially if you water late in the day.

Let the soil dry to the point where it feels very dry deep in the containers - or if the containers are plastic/small, use weight as your guide. You're actually better off to wait until you see the first signs of wilting before you water than to over-water, though drought stress isn't good either - only not as bad as over-watering.

Tell us about your fertilizer program. With what product (specifically - include NPK %s), how concentrated, how often, applied to foliage?

Al

i forgot to mention that i'm new at gardening. i don't know much about fertilizers. the miracle grow potting soil has some in it already. so, i didn't think i needed to add more for 6 months. in case of fungal disease, i have been spraying my plants with a mixture of hydrogen peroxide and water because i heard that helps. if i'm doing something wrong..please let me know.

btw, if i added organic fish emulsion to my flowers to perk them up, would that be overfertilizing? maybe the color could back to the leaves?

I'm sort of having the same problem and I appreciate this advice! I think I am probably over-watering and I am also a new(ish) gardener as well (second year with growing food) and there is a lot of trial and error, but it's so much fun and rewarding.

I have been gardening for nigh on 40 years but this year is only my 2nd year at trying to grow sunflowers. I'm having the same problem too. No creepy crawlies thank goodness. A lot of ants in my garden. Will they take nutrients from sunflowers?

Ants can sometimes mean you have an aphid problem. They like to eat the aphid secretions and will protect the aphids. But I do not remember aphids being a big problem with sunflowers.

Sunflowers need full sun and that could also be a reason for the yellowing of the lower leaves. Annual sunflowers are a weed in my area. A picture would help to see how the plant is doing by the size of the leaves. Also, where you are growing them and in what climate would help. In almost all of the mainland US sunflowers would not be getting enough sunlight or heat to be growing this time of year. I have not grown sunflowers in a long time but they did not seem to be a problem, as long as they were planted after the soil warmed up.

Looks like the same problem I'm having. What's causing mine is a worm. We recently have had leaf miners attack our citrus plants. Not sure if it's the same bug attacking the citrus, but similar damage.

The areas affected on the leaves will be soft. Inside the leaves you will probably see a few small worms.

On the citrus I have to spray with spinosad. On the sunflowers I'm removing the damaged portion of the leaves containing the bugs and destroying them.

My sunflowers are having dame problems I took one leaf off and I found worms in between layers of the burnt parts.