“How would a parking lot with 16 stalls [and the car exhaust] next to my garden interfere with plant photosynthesis?” Sylvia of Belle Plaine, Minnesota
Answer: It is a very interesting question. Car exhaust contains gasses that are helpful to plants and photosynthesis and some that are harmful. Car exhaust is also everywhere, especially if you live in an urban area, though the increase in […]
Upward curling tomato leave indicates stress more often than disease.
“Lots of my tomato plants have curling upward leaves, and in most cases only edge damage. Why?” Questions from James of Greenville, South Carolina
Answer: There is a Tomato Yellow Leaf Curl Virus, but your plant lacks several of the symptoms, including stunting, yellowing, and eventual leaf browning. Tomato plants more commonly experience physiological leaf curl when […]
“All my cabbage family plants…example broccoli, cabbage…etc. get worms on them and they eat them up. What is the best pesticide to use? I even cover them with netting and they still get wormy.” Question from Chris of Orange, Connecticut
Answer: White cabbage moths, also called cabbage loopers/worms, are the most common pest (click here to learn how to manage them) of crops in the […]
“I read that Thyme can repel deer from your veggie garden. Is it true?” Question from Sylvia of Belle Plaine, Minnesota
Answer: Thyme is a mint, and on the whole, deer dislike the strong smell of many plants in the mint family (Lamiaceae), so mints, like thyme, can repel deer. But, I cannot say whether repellent mints would keep deer away from vegetables that they […]
“I have phlox growing in a big container. The bottom leaves are looking mottled/veiny. I have fed them and also added iron, but it doesn’t seem to be improving. Is there something else it needs?” Shawn from Kenosha, Wisconsin
Answer: Tall phlox (Phlox paniculata) varieties are prone to a series of diseases and foliage disorders, but yours sounds like it is physiological leaf blight of […]
“My succulent house plants have dry leaves in the middle of the stem and black spots. Why is this happening?” Question from Karina of Wenatchee, Washington
Answer: Succulent plants can develop dry leaves when they are being either overwatered or underwatered. The black spots and the fact that leaves are drying and dying in the center of the stem indicates stem and root rot, which […]
“I have a St.Theresa grapevine that has grown and produced very well. After being devastated by Japanese beetles last year, it developed several distorted leaves. Is it possible the Japanese beetles gave it some virus or disease? I cut it way back. Now, this spring, it has been making a comeback. But I noticed yesterday that some of the leaves at the ends of […]
“What is the best organic way to get rid of whiteflies?” Question from Shawn of Kenosha, Wisconsin
Answer: Whiteflies can become awful pests to manage if the populations become large, but they are relatively easy to kill. Here is a little more information about these pests and some organic methods for handing them.
What Are Whiteflies?
Whiteflies sucking insects that remove the juices from plant leaves and […]
“How does one get rid of [Canada] thistle?” Question from J Marsh of Fenton, Michigan
Answer: I am so sorry that you have this plant in your garden. Canada thistle (Cirsium arvense) is by far one of the worst of all garden weeds. It has painfully prickly foliage and produces lots of early summer flowers that produce copious puffy seeds that are distributed by wind and […]
“What’s the best flower to control unwanted bugs in your veggie garden?” Question from Sylvia of Belle Plaine, Minnesota
Answer: Some commonly recommended companion plantings are ineffective, while others are supported by research. Most of the research surrounds vegetable crops and companion plants that reduce the number of insect pests that attack these crops. Companions fall under two categories:
Trap crops: These plantings attract insect pests, luring […]
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