Why are some of my begonias turning brown?

I have several begonia plants.They were all planted at the same time,but in the last few months I have noticed that some of the plants are turning brown and some are looking really good,nice and green and lots of flowers.About 4 months ago I repotted them into larger containers with fresh soil.They were doing great for awhile.Any suggestions?

Why are some of my begonias turning brown?
Either to much water or not enough; do you have good drainage? Sometimes if the water doesn't drain it will cause the plants to get root rot. Check out your potting situation and give them miracle grow and they should do fine.
Reply:brown is under watering, generally. Put your finger in the soil to test the moistness. If the soil sticks then don't water, if it's dry then do.
Reply:you may want to get a watering timer and make sure they are getting enough nitrogen so test the soil to make sure
Reply:Some may be undergoing transplant shock. Cut them back. Clip off all the stems that look weak and all the stems that have brown leaves. Isolate these plants from the others in case there is a disease. To test for infestation, hold a piece of white paper under some of the leaves; tap the leaves; see if any little bugs like mites fall unto the paper. If bugs appear, take the plant to a local nursery to determine what treatment you need. Sounds mostly like tranplant shock though. The ones you clip, remove to a non-sunny area for a few days and hold back on the water. Be patient, but they will show new growth if none of the other problems exist.
Reply:It's probably those damn kids in the neighborhood running around with brown spray paint. They like to spray everything in site and from what I hear, especially begonias. They are one of the favorite targets of those "spray painting fools". Try hiding behind the begonias and when they come by to spray them brown, jump out and say, "Boo, don't spray those begonias". That should work---scare those little buggers to death. Good luck...Brown Begonias can be a real problem.
Reply:'Cause they want to be gone? I don't know. Over-watering, or maybe contaminated soil? Tiny bugs?
Reply:put a little epsom salts in you water then water your plants , can be done about every 2-3 months. it really greens them up nice.
Reply:Maybe because it's fall. Are the beognia's indoors or out?
Reply:Sounds like your over watering them.
Reply:It depends on what kind of begonias you have. Tuberous begonias, at this time of year, are getting tired, and need a rest. If you've got tuberous begonias either stop watering, and cut the stem to dirt level, or take out the tuber and store it till next year. If you cut the stem water a little once a month, or until you see new growth.
Reply:well it sound like too much water to me. usually begonias are pretty hardy unless the stay too wet, if they are, you might want to ck for slugs or snails cause they love moisture and begonias are one of their favorite dish. if you find any snails use DE-diatomaceous earth is a deficant powder which will suck the moisture right out of their body. it will kill them in one day. if its root rot, then just let them dry up and cut anything that looks bad, wait about a week or so and then fertilize to get them to grow back thicker.