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Bill Robinson
  MARCH  2015
In my last few articles I have had a lot of fun and I hope my readers have too. This newspaper column must keep the theme of plants and gardening so be that as it may. Let’s assume I received a phone call at 8 am this morning from a crying young female trying to tell me her prized green plant has yellow leaves on it. She insist that I must come over and find out what is wrong as she can barely speak on the telephone. So I go over to her house and find the plant on the porch with some yellow leaves on it. A close inspection reveals green veins in the leaf with yellow areas between. This condition is almost always chlorosis which indicates a lack of nutrition.
I’ve had this condition a number of times in the greenhouse and finally found through some research that there are two major things to consider. The first is obvious, lack of fertilizer but the second one is very seldom considered; improper pH value. These two things very closely interrelate. I’m sure some gardeners know more about their pool pH than their garden soil pH. 
 In my greenhouse I know through fertigation that I have plenty of fertilizer so I know pH is the problem. pH is based on a scale of 1-14 with 7 being neutral as 1-7 being acid and 7-14 being alkaline. When the soil tests to much either way from 7 the nutrients are not available to the plants. With few exceptions a pH range of 5.5 to 7.5 will work most of the time.
To go down the scale add powdered Sulphur, to go up the scale add lime. Just to add insult to injury the scientists made the pH scale logarithmic instead of mathematic. An example; to go from 8 to 7 add 5 pounds, to go from 8 to 6 add 50 pounds to go from 8 to 5 add 500 pounds (the exponent is 10) so now you can see how hard it is to move up and down the scale. Well the lady had just fertilized this plant two weeks ago so being an acid loving gardenia I added a small amount of powdered Sulphur and watered it in.
Two weeks later i received a happy thank you call finding out the gardenia was all green again plus an invitation for dinner. We had tropical drinks in the gardenia lounge before having an excellent meal.

 Watch your pH . . . . . Broccoli Billy

Copyright © by Bill Robinson 2015