Question
The leaves of my sunflower plants are turning brown and are translucent.  I am a novice, south Florida gardener trying to grow organically.  Do you have any insight to this problem?  
Thanks.

Answer
Gretchen,
Fungal problems might turn leaves brown, but they usually do this in a spotty manner, not the entire leaf at one time unless the fungus is attacking the stem. Usually this is seen in conditions that are too wet, because most fungi need damp conditions to flourish. Have you had a lot of rain or are you watering frequently?  For most plants, a deep soaking less often is best, not watering every day. If you soak the soil deeply then the plants can go for a few days without watering.

Another thought that occurs to me is this: have they been watered recently with water that might have started out being hot from the hose?  You know how sun makes the water in a hose very hot - might that have hit these leaves?  I once saw another type of plant get translucent leaves that looked as if they'd been hit by a frost, but it was the hot water from a hose.

all the best,
C.L.


Gretchen,
Have the flowers stopped blooming and started (or finished) making seeds? If so, this is the natural way that a plant shuts down. True sunflowers have a very short life - they grow for two to three months, bloom, make seeds, and then die. If your sunflowers have not yet bloomed, they might have dried up. Since you garden organically, we know it's not fertilizer burn from synthetic fertilizers. And since you live in south Florida it's not that they went through a frost! If the plants were too wet the leaves would first all yellow, and then turn brown.  So it sounds to me like either the plants are done for the season, and you can plant new seeds next spring for more, or they have dried out.

I hope this helps,
C.L.