Monday, September 23, 2013

Heavy Rainfall Causes Tomato Problems by Mary Small

Fruit Splitting Caused by Too Much Water photo by Mary Small

There are some strange things happening to my tomato plants. They are wilting, some have blossom end rot and some fruit is splitting open.  Don’t plants wilt when they need water? Isn’t blossom end rot due to irregular watering? Well, yes, but………
Plants can wilt when there’s excess water around, like the 6 inches that fell on my garden. Soil contains pore space between the mineral and organic particles, some holding water and some holding oxygen.  But when a lot of water is applied to the soil, it drives the oxygen out.  Soil oxygen is needed by plants to perform various functions.  No (or low) soil oxygen damages or kills roots and these damaged roots can’t absorb nutrients and water.  So plants wilt. 

Weeks have gone by with no sign of blossom end rot, so why am I finding it now? Blossom end rot occurs when there’s not enough water to move calcium, which is absorbed by roots, into the fruit.  Even though there’s plenty of water around to move the calcium, the roots are either poorly functioning or non-functional (see above paragraph).  The calcium still isn’t getting to the fruit for its proper development.  Fortunately, tomatoes are still edible after removing the damaged area!
Fruit splitting happens when the fruit absorbs a lot of water and expands faster than the skin of the tomato.  The cracks are attractive to disease organisms as well as insects looking for a sweet drink!  Fruit that is not rotting, smelly or oozing can be harvested and used quickly, before rot does set in. Otherwise, send them to the compost pile.
Blossom End Rot photo by Mary Small

Tomato Splits photo by Mary Small