Ask A Master Gardener
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Q. How can I boost my success rate when transplanting garden plants?
A. Soak the soil you are transplanting into at least twice before you add the new plant, then soak it once again after the plant is in the ground. Another trick that has been successful is: dig the hole, add a handful of compost or manure, completely fill the hole with water, then add the plant. In either case, maintain adequate moisture levels until plant is established.
(Thanks to Deb P. and Lisa D. for these tips)
A. Soak the soil you are transplanting into at least twice before you add the new plant, then soak it once again after the plant is in the ground. Another trick that has been successful is: dig the hole, add a handful of compost or manure, completely fill the hole with water, then add the plant. In either case, maintain adequate moisture levels until plant is established.
(Thanks to Deb P. and Lisa D. for these tips)
Grass & Turf Lawn
Q. What do I do about moss in my yard?
A. Moss in a yard is a symptom of a bigger problem, and killing it off will only be temporary unless overall conditions are improved. Moss grows in moist conditions. If the yard is shaded, grass is not happy so moss out-competes it. If there is moss in a yard in a sunny location, my guess is that there is a “layer” in the soil—a compacted bottom layer or a change in soil type. This happens during construction or if topsoil is brought in from off site. Low fertility can contribute to the problem. The solutions are complicated. If it’s a shady site, it will be difficult to ever get grass growing there, so turn it into a hosta bed! If it’s a sunny site, they could start with a heavy aeration to try to break through layers/compaction. Then fertilize and overseed. This would be another case where more conversations with the people is necessary to find out exactly why moss is growing in their yard!
A. Moss in a yard is a symptom of a bigger problem, and killing it off will only be temporary unless overall conditions are improved. Moss grows in moist conditions. If the yard is shaded, grass is not happy so moss out-competes it. If there is moss in a yard in a sunny location, my guess is that there is a “layer” in the soil—a compacted bottom layer or a change in soil type. This happens during construction or if topsoil is brought in from off site. Low fertility can contribute to the problem. The solutions are complicated. If it’s a shady site, it will be difficult to ever get grass growing there, so turn it into a hosta bed! If it’s a sunny site, they could start with a heavy aeration to try to break through layers/compaction. Then fertilize and overseed. This would be another case where more conversations with the people is necessary to find out exactly why moss is growing in their yard!
Trees & Shrubs
Q. Will black walnut roots cause wilt in cucumber or other vegetable plants?
A. Yes, it can. Black walnuts exude a compound called juglone, which basically tries to knock out the competition. While some plants are tolerant of juglone, many are not. While there is not enough hard research on this topic, there are lists that have been compiled of plants that are affected and tolerant. Wilting of plants is a common symptom, especially in tomatoes. If you have a big black walnut tree, DON’T plant your vegetable garden within 80 feet or so. For more info on walnut toxicity, see the Extension publication.
Q. Have a pagoda dogwood tree and the leaves get black spots that then turn red and the tree is dying. What is it?
A. Dogwoods get a variety of leaf spots, caused by different fungal pathogens. It’s hard to say exactly what is causing the spots. But the spots on the leaves are probably not killing the tree, as leaf spots are usually more of a cosmetic issue. One of the most common diseases of pagoda dogwood is Golden Canker. This gets on branches and twigs and is very easy to diagnose—it is a bright golden color, like goldenrod, and it will kill the branches or trunks. In this case, I would want to talk more with the tree owners and find out more about what might be killing the tree.
A. Yes, it can. Black walnuts exude a compound called juglone, which basically tries to knock out the competition. While some plants are tolerant of juglone, many are not. While there is not enough hard research on this topic, there are lists that have been compiled of plants that are affected and tolerant. Wilting of plants is a common symptom, especially in tomatoes. If you have a big black walnut tree, DON’T plant your vegetable garden within 80 feet or so. For more info on walnut toxicity, see the Extension publication.
Q. Have a pagoda dogwood tree and the leaves get black spots that then turn red and the tree is dying. What is it?
A. Dogwoods get a variety of leaf spots, caused by different fungal pathogens. It’s hard to say exactly what is causing the spots. But the spots on the leaves are probably not killing the tree, as leaf spots are usually more of a cosmetic issue. One of the most common diseases of pagoda dogwood is Golden Canker. This gets on branches and twigs and is very easy to diagnose—it is a bright golden color, like goldenrod, and it will kill the branches or trunks. In this case, I would want to talk more with the tree owners and find out more about what might be killing the tree.
Fruit
Q. Why do apples drop off early when they are little and green?
A. There are two reasons small green apples drop. Usually, those apples have not been well pollinated. If pollination would result in only a couple of seeds in the fruit, the tree (whose goal is to reproduce) decides it’s not worth the energy to produce the fruit, and instead uses the energy to expand those fruit which have been fully pollinated. Some apples might be lopsided—flat on one side—which also indicates the seeds on that side of the apple were not pollinated. Trees also sometimes “self-thin”. If fruit set is really heavy, the tree might drop some fruit knowing it won’t have enough resources for all of them. If they don’t self-thin, the fruit might all be smaller than normal.
Q. Concord grape has leaf galls.
A. This is very common—grape leaves get “bumps” from an insect called grape phylloxera. It builds up over time. Only when it gets really bad does it reduce yield, and then an insecticide can be used.
Q. Raspberries have little white worms in them.
A. This is probably the Spotted Wing Drosophila that has become a major problem. Google “Spotted Wing Drosophila Wisconsin” and you will get to the University’s site about this pest with all the latest info. Note: Traps are only to determine if you have it, but traps will NOT protect the fruit—spraying is the only option.
A. There are two reasons small green apples drop. Usually, those apples have not been well pollinated. If pollination would result in only a couple of seeds in the fruit, the tree (whose goal is to reproduce) decides it’s not worth the energy to produce the fruit, and instead uses the energy to expand those fruit which have been fully pollinated. Some apples might be lopsided—flat on one side—which also indicates the seeds on that side of the apple were not pollinated. Trees also sometimes “self-thin”. If fruit set is really heavy, the tree might drop some fruit knowing it won’t have enough resources for all of them. If they don’t self-thin, the fruit might all be smaller than normal.
Q. Concord grape has leaf galls.
A. This is very common—grape leaves get “bumps” from an insect called grape phylloxera. It builds up over time. Only when it gets really bad does it reduce yield, and then an insecticide can be used.
Q. Raspberries have little white worms in them.
A. This is probably the Spotted Wing Drosophila that has become a major problem. Google “Spotted Wing Drosophila Wisconsin” and you will get to the University’s site about this pest with all the latest info. Note: Traps are only to determine if you have it, but traps will NOT protect the fruit—spraying is the only option.
Vegetables & Herbs
Q. Onions are small. Soil is sandy. Rabbit and chicken manure was used.
A. Onions are actually BIG feeders! They need plenty of nitrogen to grow big. Manure is relatively low in nitrogen, compared to synthetic fertilizers. Onions should be given nitrogen at planting, and again 6 weeks later. Synthetic high nitrogen fertilizer can be used, or, organic choices that are higher in nitrogen include blood meal and fish emulsion.
Q. Why are ends of tomatoes rotting?
A. Classic Blossom End Rot, where the end of the tomato fruit opposite the stem turns black, sinks, and rots. This is caused by a lack of calcium getting into the fruit. It does NOT mean you need to add calcium to the soil, as RARELY is there a deficiency. Rather, the calcium is not being taken up by the plant efficiently and moved to the developing fruit. This is usually caused by uneven moisture, where the soil gets dried out before being watered. The solution is to maintain even moisture. We see this problem more with the early fruit produced, and more with tomatoes planted in containers because the containers dry out faster than an in-ground garden does.
Q. Vegetables including peppers and melons didn’t set.
A. I assume this means they didn’t get fruit. There are a couple possible reasons. If it was really hot when the flower buds were at the right stage, they may have “aborted” so no fruit formed. Also, if the flowers were not pollinated, no fruit would form. I would also ask and make sure they are growing in full sun!
Q. Will black walnut roots cause wilt in cucumber or other vegetable plants?
A. Yes, it can. Black walnuts exude a compound called juglone, which basically tries to knock out the competition. While some plants are tolerant of juglone, many are not. While there is not enough hard research on this topic, there are lists that have been compiled of plants that are affected and tolerant. Wilting of plants is a common symptom, especially in tomatoes. If you have a big black walnut tree, DON’T plant your vegetable garden within 80 feet or so. For more info on walnut toxicity, see the Extension publication.
Q. What is "catfacing" on tomatoes and what can we do about it?
A. Insect damage, poor pollination, and environmental factors all cause catfacing, a term that describes the puckering, scarring, and deformation of strawberries, stone fruits, and tomatoes. You can recognize catfacing in tomatoes by the scarred indentations found on the blossom end of the fruit. Sometimes this scarring extends deep into the fruit cavity, making much of the fruit inedible. For images of what catfaced tomatoes look like, go here.
The most common cause of catfacing in tomatoes is exposure to temperatures below 50 degrees F during flowering and fruit set. Low temperatures inhibit pollination and cause the blossom to stick to the developing fruit. Both of these factors prevent certain parts of the fruit from developing. The undesirable scarring and indentation occurs when unaffected parts of the fruit continue to expand.
Tomatoes that develop during warm weather do not usually experience catfacing problems. However, evidence suggests that even when temperatures are warm, excessive soil nitrogen, exposure to the pesticide 2,4-D, and erratic soil moisture can cause catfacing.
Some cultivars and varieties, including many heirlooms, are more susceptible to catfacing. You can avoid the problem by choosing resistant varieties, such as 'Homestead' and 'Monte Carlo'. If your favorite varieties are susceptible but you'd still like to grow them, either protect your transplants with cloches in cold weather or wait until day and evening temperatures are consistently warm to plant them. Catfaced tomatoes are safe to eat; simply cut away the scarred areas.
A. Onions are actually BIG feeders! They need plenty of nitrogen to grow big. Manure is relatively low in nitrogen, compared to synthetic fertilizers. Onions should be given nitrogen at planting, and again 6 weeks later. Synthetic high nitrogen fertilizer can be used, or, organic choices that are higher in nitrogen include blood meal and fish emulsion.
Q. Why are ends of tomatoes rotting?
A. Classic Blossom End Rot, where the end of the tomato fruit opposite the stem turns black, sinks, and rots. This is caused by a lack of calcium getting into the fruit. It does NOT mean you need to add calcium to the soil, as RARELY is there a deficiency. Rather, the calcium is not being taken up by the plant efficiently and moved to the developing fruit. This is usually caused by uneven moisture, where the soil gets dried out before being watered. The solution is to maintain even moisture. We see this problem more with the early fruit produced, and more with tomatoes planted in containers because the containers dry out faster than an in-ground garden does.
Q. Vegetables including peppers and melons didn’t set.
A. I assume this means they didn’t get fruit. There are a couple possible reasons. If it was really hot when the flower buds were at the right stage, they may have “aborted” so no fruit formed. Also, if the flowers were not pollinated, no fruit would form. I would also ask and make sure they are growing in full sun!
Q. Will black walnut roots cause wilt in cucumber or other vegetable plants?
A. Yes, it can. Black walnuts exude a compound called juglone, which basically tries to knock out the competition. While some plants are tolerant of juglone, many are not. While there is not enough hard research on this topic, there are lists that have been compiled of plants that are affected and tolerant. Wilting of plants is a common symptom, especially in tomatoes. If you have a big black walnut tree, DON’T plant your vegetable garden within 80 feet or so. For more info on walnut toxicity, see the Extension publication.
Q. What is "catfacing" on tomatoes and what can we do about it?
A. Insect damage, poor pollination, and environmental factors all cause catfacing, a term that describes the puckering, scarring, and deformation of strawberries, stone fruits, and tomatoes. You can recognize catfacing in tomatoes by the scarred indentations found on the blossom end of the fruit. Sometimes this scarring extends deep into the fruit cavity, making much of the fruit inedible. For images of what catfaced tomatoes look like, go here.
The most common cause of catfacing in tomatoes is exposure to temperatures below 50 degrees F during flowering and fruit set. Low temperatures inhibit pollination and cause the blossom to stick to the developing fruit. Both of these factors prevent certain parts of the fruit from developing. The undesirable scarring and indentation occurs when unaffected parts of the fruit continue to expand.
Tomatoes that develop during warm weather do not usually experience catfacing problems. However, evidence suggests that even when temperatures are warm, excessive soil nitrogen, exposure to the pesticide 2,4-D, and erratic soil moisture can cause catfacing.
Some cultivars and varieties, including many heirlooms, are more susceptible to catfacing. You can avoid the problem by choosing resistant varieties, such as 'Homestead' and 'Monte Carlo'. If your favorite varieties are susceptible but you'd still like to grow them, either protect your transplants with cloches in cold weather or wait until day and evening temperatures are consistently warm to plant them. Catfaced tomatoes are safe to eat; simply cut away the scarred areas.
Weeds & Invasives
Q. How do you control invasive weeds in raspberries?
A. Raspberry patches can be overrun with perennial weeds, especially quackgrass, over time. There are a couple of options. Because quackgrass is a cool season grass, it becomes active in spring before the raspberries do. You can therefore spray glyphosate (Roundup) on the grass BEFORE any green shoots appear on the raspberries. This can also be effective in late fall after raspberries have gone dormant. Once the grass is removed, heavy mulching can keep weeds from invading the patch.
Q. Wild parsnip and scarring?
A. I’m assuming this question was about if wild parsnip will cause scarring on the skin. It can! Wild parsnip has an oil that can get on the skin and cause hyper photosensitivity—in other words, just a small about of sun exposure will cause severe sunburn. Severe sunburn is damage to the skin, and if it’s bad enough, it could cause permanent scarring!
A. Raspberry patches can be overrun with perennial weeds, especially quackgrass, over time. There are a couple of options. Because quackgrass is a cool season grass, it becomes active in spring before the raspberries do. You can therefore spray glyphosate (Roundup) on the grass BEFORE any green shoots appear on the raspberries. This can also be effective in late fall after raspberries have gone dormant. Once the grass is removed, heavy mulching can keep weeds from invading the patch.
Q. Wild parsnip and scarring?
A. I’m assuming this question was about if wild parsnip will cause scarring on the skin. It can! Wild parsnip has an oil that can get on the skin and cause hyper photosensitivity—in other words, just a small about of sun exposure will cause severe sunburn. Severe sunburn is damage to the skin, and if it’s bad enough, it could cause permanent scarring!