We cleaned a flood tank with chlorine and forgot to flush it out before using to flood poinsettias. We not have quite a bit of yellowing and leaves falling of. Will the chlorine continue to have activity in the soil or is the damage done. Should we try to leach? it has been four days since the irrigation.

It is hard to say how long the chlorine will remain active in the soil but our initial thinking is that most of the damage has been done. Leaching the excess chlorides out is important but we think you should water with a weak fertilizer solution to displace and replace the ions rather than watering with clear water.

You may continue to see leaf yellowing and drop as well as black streaking on the stem and the undersides of the leaves. It will be important now to keep the plants as happy as possible and not add to the stress of the chlorine injury. If the roots were damaged you may want to make a fungicide application in a few days to help prevent root rotting pathogens that can enter the roots through the damaged tissue. Excess chlorides in the soil slow the uptake of water so it will also be important to make sure you don't let the plants dry out too much while they are recovering. Hope this helps...good luck with the crop.