Q. What is causing our tomatoes to have curled leaves? Could it be too
much water? We are watering with two PVC lines per 10’x34″ vegetable box.
Have been watering twice a day as the temperatures have been in the 90 degrees many weeks (live in southern California). We notice the water does come out from the bottom of the boxes into the surrounding soil – boxes are 12″ deep but the soil is about an inch below edge of box – Dr. M’s books say to level but we find that the water runs off too quickly when soil is that high.
Also, some of the plants have rusty or dried leaf edges, What could cause that? We looked in the three volumes of Dr. M’s -The Garden Doctor, and it showed too much fertilizer can cause dry leaf edges. Do you think that is the case?
A. Curled leaves could be because the leaves are old; it could be because of the heat; it could be a general deficiency; it’s highly unlikely that it’s too much water directly.
If you’re watering twice per day I recommend you consider applying less fertilizer and do it twice each week. Very frequent watering can leach the fertilizers out of the Grow-Boxes, and you can end up with a general deficiency and slow your plants’ growth.
Unless you’re applying more fertilizer than prescribed your dry leaf edges are not excess fertilizers. Lack of potassium can cause dry leaf edges, and I suggest you try applying some potash fertilizer one time between regular feedings, using 12-16 ounces per 30′-long bed.