Answer: Based on your description it is a bit difficult to tell what is happening, but here are some possibilities. Sunflowers grow very quickly and for this reason are generally started in the ground rather than in pots. If the pots are too small it will stunt the plants. They are also sun lovers, so if the light levels are too low they will decline. For the same reason, they need ample air circulation and again, plenty of room. Finally, if the soil is too wet or too dry it can cause problems. Try to keep it evenly moist like a wrung out sponge rather than sopping wet or very dry. It is also possible that there is a disease problem, in which case starting again with clean tools and supplies (rinse them with nine parts water to one part bleach solution) along with assuring them ample light, air and water should help.
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