August 10, 2011
We finally have gotten some much-needed rain. The vegetable plants should be very happy!
Speaking of vegetable plants, do your tomato plants look like they have gotten skinny? During the past 10 days, we have had many people who have come into the store with stories about how there tomato plants look different. When the customer has looked at the plant over several days, it has finally occurred to them that the tomato plants are losing their leaves. The leaves are not falling off the plants; the leaves are just disappearing from the plant! Upon closer look, people find out that the leaves are being eaten. Upon close examination of the plant, they may find the culprit. The creature eating the leaves on the tomato plants is the tomato hornworm. The tomato hornworm is a green colored caterpillar. Its color allows it to blend in with the leaves of the tomato plant. They start off as a small caterpillar, but their appetite for tomato leaves allows them to very quickly grow to a large size. Last week, we had a customer who brought one into the store. The caterpillar was about 4 to 5 inches long and about as big around as a man’s thumb. As the hornworm grows in size, it may also start to eat the green tomatoes.
There are many different control methods you can use to kill this caterpillar. A search online will tell you to use a product called BT. This is a bacterium that kills just caterpillars. The problem with using it on hornworms this late in the creature’s life is that it may not work in time to kill the caterpillars before they defoliate the plants. You can use Sevin as a dust or a spray or you can use Pyrethrum. Pyrethrum is a more organic approach. There are also several synthetic forms of Pyrethrum that last longer on the leaves. Ultimately, if you can find the caterpillars, you can pick them off the plant and add them to the weekly trash bag.
As the tomato plants grow, they are now beginning to set lots of green tomatoes. In order for those tomatoes to ripen, the tomato plant will use lots of fertilizer. For the ripening process to happen, make sure you use a fertilizer with lots of potassium. Potassium is the third number on the fertilizer package. Make sure that you regularly apply the fertilizer from now until all of the tomatoes have ripened. This may be right through the month of September. If you skip even one application, you will wind up with a lot of green tomatoes as the first frost arrives.
In my last column, I had written about using soaker hoses to water your plants. A few people have asked about how long the soaker hoses should run to allow the plants to get enough water. The answer really lies in the quality of the soil. If the soil is on the sandy side, you will have to water longer. If the soil has some clay, you will have to water less. Ultimately, what you need to do is to turn on the soaker hose and let it run for ½ an hour. Go out to the garden and pull back some soil and see how far down the soil is moist. If the soil is moist down 3 to 4 inches, then you can stop watering. If not, let it run another ½ hour and check again. Eventually, you will know how long you have to run the sprinkler to get the soil moist down to the depth of 3 to 4 inches. You will need to water again when the soil is dry at a depth of 1 inch. You can use your finger as a guide. If you put your finger into the soil to about the second knuckle and the soil feels dry, it is time to put the soaker hoses back on.
Well, that’s all for this week. I’ll talk to you again next week.