Since we last talked, there have been a few things going on in the gardens. The vegetable gardens have seen an increase in the appearance of fungus diseases.
Fungus diseases thrive in cool and damp weather. When you have dew settle on your plants, the dew makes the leaves wet and fungus diseases begin to grow. We had rain Thursday night into Friday morning. This rain in the relatively cooler night can lead to fungus diseases.
Tomato plants have begun to develop leaf spots and in some cases early or late blight. If you recall, late blight pretty much wiped out all the tomato plants a few years back. You will find that powdery mildew has settled in on squash and cucumber leaves. This disease will kill the leaves in short order.
As soon as you can, go out and look at your vegetable plants. If you see yellowing of the leaves, brown spots on the leaves or what looks like white powder on the leaves, you need to treat your plants with an appropriate fungicide. Once a fungus disease has begun, some fungicides will not stop the disease. You can take a few leaves off your plants, put them into a clear plastic bag and bring them to the store. We can identify the problem and then show you the proper fungicide to effectively control the problem.
Insect problems have been on the rise on both flower and vegetable plants. The hot weather in July allowed spider mites to get established on many plants. Spider mites do feed on tomato leaves. They also feed on verbena and dwarf Alberta spruce. Sometimes, you will see the webbing formed by large numbers of this mite.
Generally speaking, the first sign of this insect feeding is the leaves of your plants developing a gray coloration. By the time you see the webbing, you have a major infestation happening on your plants. The problem with spider mites is that they go from egg to reproducing adult in less than a week. You can use a systemic insecticide on ornamental plants, but you should not use one on vegetable plants. Many insecticides are labeled for use on spider mites. The unfortunate thing is that many are not very effective at controlling this insect. If you think you have spider mites on your plants, clip off a few leaves or some of the discolored needles on your evergreens, place them in a clear bag and bring them into the store for us to identify the problem. We can recommend the correct insecticide for the particular plant that the spider mites are attacking.
We are still having customers with issues concerning the growth of their vegetable gardens. Often, the problem is that the plants are not being fertilized as often as they should be fertilized. Early in the season, you may be able to fertilize the plants once a month. At this time of the growing season, your plants are getting very big, and they are trying to set the vegetables, too. This requires a lot more fertilizer to keep the plants going strong. With vegetable plants, you need to fertilize the plants until the plants no longer produce vegetables or until the fall frost kills the plants.
When you get those green tomatoes and they are not ripening, it usually means that the tomato plants are not getting enough fertilizer. This is critically important on those late-season tomatoes. Choose whatever fertilizer is appropriate for vegetables, and keep on fertilizing your plants. You will find that, in many cases, you will have to fertilize every 10 to 14 days.
Japanese beetles are still feeding, and they can do a lot of damage to your plants. A regular application of neem oil on your plants will help to control these beetles. Remember that these beetles lay eggs in your lawn. The eggs hatch out as the white grubs that kill the roots of your lawn. It is best to apply your grub control in the fall to kill the grubs while they are still small. If you wait until spring to control the grubs, they grow very quickly, and at some point, grub control methods are not effective.
Well, that’s all for this week. I’ll talk to you again next week.
Tim Lamprey is the owner of Harbor Garden Center on Route 1 in Salisbury. His website is www.harborgardens.com. Do you have questions for Tim? Send them to firstname.lastname@example.org, and he will answer them in upcoming columns.