This is the Q&A for the Yard and Garden show for June 30, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.
Guest Host: Connie Fisk, Cass County Extension Educator
If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/44qr and be entered to win a free plant book or some free UNL gifts.
1.The first caller of the day wanted to know if he could fertilize his tomatoes, potatoes, and cucumbers with the same fertilizer?
A. Yes, the same product could be used for all three of these crops. Be careful when fertilizing to not use too much Nitrogen during the bloom period which will cause the plants to grow large but not produce any fruits. Also, too high of Nitrogen for the plants can lead them to grow large and dense which can lead to more fungal diseases.
2. A question came through email asking what would cause red spots on strawberry leaves?
A. This could be either due to leaf scorch or leaf blight. The leaf scorch will have red spots that have a red or purple center and the leaf blight will be a red spot with a gray center. For both of these diseases, you can use Captan fungicide.
3. How soon can peonies be cut off?
A. Peony leaves should be left on the plant through the growing season and can be removed in the fall when the leaves turn yellow. Otherwise, this time of the year you should only remove the flower stalks. Leaving the leaves on the plant will help the plant build sugars to help it bloom early next year.
4. A caller planted Karl Forester Reed Grass in 2 locations in his landscape at the same time this spring. One location, the grasses are doing well, but in the other location, the grasses are much smaller and not growing well. The worse plants are on the east side of the house while the good grasses are on the west side of the house. What would cause them to grow so differently?
A. The east side of the house would be in more shade than those plants growing on the west side. Most of our grasses like to be grown in full sun, this difference in sunlight could cause the difference in growth. Because they are in different locations, a nutrient deficiency could be causing the few on the east side to be growing less. Add a general fertilizer to help with growth.
5. This caller is applying a fertilizer with 24% Nitrogen every 7 days to her tomato plants. Is this too high of a percentage of Nitrogen for the plants to grow well?
A. The percentage isn’t as important as how much is applied. Applying a fertilizer every 7 days is too often. For most vegetable gardens, fertilizing three times a year will be sufficient. With this high of Nitrogen in the soil the plants will not produce and may grow too large and develop diseases in the deep canopy.
6. A caller had golf ball sized hail a couple of weeks ago that hit his tomato plants. The plants are still growing and have leaves on them. Will they be ok?
A. Yes, they should be fine. Keep them mulched to help reduce competition with weeds and keep them uniformly watered as needed. Don’t fertilize the tomatoes because they are stressed from the storm damage and fertilizing a stressed plant will increase the stress.
7. This caller wondered if grass clippings will negatively affect the soil in his vegetable garden? He had been using the grass clippings for a couple of years and now his vegetable plants don’t look as healthy as before he started using grass clippings.
A. After discussions, the caller said he had been using herbicides on his lawn and using the grass clippings on his garden. Pesticides can have a long residual on the grass clippings and this can negatively affect the plants. Especially if he was using broadleaf herbicides such as 2,4-D for dandelions. Broadleaf herbicides will damage vegetable plants which are all broadleaf plants. It would be best to avoid using his grass clippings if he is to continue using herbicides on his lawn. He can use other types of mulch such as straw, woodchips, newspaper, cardboard, or grass clippings from a neighbor who isn’t using herbicides on his or her lawn.
8. A caller has hollyhocks that have copper colored, round spots on the leaves and the leaves are falling off. What is the problem and what can be done to improve the flowers?
A. This is likely due to hollyhock rust, a common fungus of hollyhocks. Remove the leaves as they develop the disease and destroy the leaves and plant parts removed in the fall cleanup. Fungicides can be used if necessary, such as a liquid copper fungicide.
9. Do weeds need to be controlled in sweet corn or will the plants grow tall enough and shade them out soon?
A. Weeds should always be removed to reduce competition and lead to better overall plant growth. You can hoe the weeds out and use mulch between rows.
10. This caller has squash plants growing in black containers that are growing in potting soil. They are not thriving, what could be the problem?
A. The pot could be getting too hot because it is black. It would be beneficial to add mulch around the container or paint it another color to keep the roots cooler inside. It also could be drought stressed. Plants grown in a container get drought stressed sooner and need to be watered more than those growing in the ground because they have more limited root space. It also might be beneficial to add a general fertilizer to help the plants grow better.
11. A caller has flagging on cedars that is causing the tips of the branches to turn brown. What would cause this damage to 20 year old cedars?
A. This could be due to bagworms which would be very small yet. Bagworms can be sprayed with any general insecticide. It also could be due to drought stress or Kabatina tip blight. There is no fungicide control for Kabatina. The best management is to cut out the affected areas.
12. This caller has sweet corn growing in his garden. The corn is about 2 feet tall and is now tasseling and it is very light colored. What would cause this problem? He is watering his garden for 1.5-2 hours every night.
A. This is likely due to overwatering. Vegetable gardens need about 1 inch of water per week, watering every night is not necessary and that much water would cause the nutrients to leach down through the soil, which would account for the lighter green coloration. The corn will likely not produce this year since it is already tasseling.
13. A caller wondered if the wood chips being produced from all of the downed trees would be safe to use as mulch around living plants or if there would be an issue with insects in the mulch?
A. This would make a good mulch for your plants. If there was an insect in the trees being chipped, the chipping process will kill it.
14. This caller has grapes that were hit by herbicide drift this spring. The leaves were all the size of a nickel and deformed, but the plants are not pushing new growth. What should they do to help the grape plants make it through this stress? Should they fertilize the plants?
A. Unfortunately, grapes are very sensitive to herbicide drift. 2,4-D can drift about 1/2 miles and Dicamba can drift about 1 mile, so it can move from a long way and grapes will be the first to know. If these are mature plants and they are pushing new growth, they should be fine. Don’t fertilize the plants, this will add more stress to the situation. Keep them well watered to help them through.
15. A maple tree was recently hit by hail. Now the trunk and branches have wounds on them. Should anything be done to cover these wounds?
A. No, don’t apply anything to the tree or cover the wounds with anything. Allow the tree to go through it’s normal processes to seal up the damage to reduce decay further into the trees.
16. A caller has cantaloupe plants that are not growing well. They have very small leaves but they are flowering already. What can be done to help them grow better? They are growing in a garden with many other vegetable crops that are growing much better.
A. Remove the flowers that are developing on such a small plant. When plants try to push flower growth and fruiting, they reduce their growth. Removing the flowers will push the plants to try to grow more before they begin flowering.
17. This caller is growing strawberries that have been growing for a few years. They bloomed and looked healthy this year, but the strawberries produced were very small. What would cause this problem? Also, what will help stop strawberries from rotting if they ripen on the ground?
A. The plants should be thinned at the end of the year to help increase the size of the berries. They also could be dealing with an issue of poor pollination. The cool, wet weather this spring led to low pollination because the bees don’t like to fly in the rain. Poor pollination may lead to development of the fruits, but at a much lower size than normal. Poor pollination can also cause the plant to drop small fruits from the plant before they mature. Mulch the strawberry beds with straw to help keep the berries from laying on the soil and rotting as they mature.
18. A caller from the Geneva area has an ash tree. Should he be treating for Emerald Ash Borer now?
A. No, Emerald Ash Borer (EAB) has only been found in Greenwood and Omaha in Nebraska and we recommend waiting until the beetle has been found within 15 miles of your tree before beginning treatments to reduce injury to the trees and to reduce the amount of insecticides in the environment. There is no need to treat for a problem that we don’t have yet.
19. This caller has one apple tree and needs to get a second tree for pollination. What would be a good variety?
A. It is necessary to plant a second variety of apple tree to help increase pollination. Look at the local nurseries to find good choices that go with the variety you already have planted. They will have a chart to show which trees pollinate which.
20. A caller has a fungus in the lawn every year. This fungus shows up in different locations throughout the yard every year and she treats with a fungicide every year. Is there anything she can do to make it so she can stop treating every year?
A. If you see the fungus in your lawn every year, you would need to treat for it earlier in the year before the fungus appears. If the fungus is present before treatments begin, they will not stop the damage that is already present.
*A caller later on the show suggested that these spots may be due to a dog urinating in the lawn, which can cause brown spots similar to many of our summer fungal diseases. There is no way to stop the brown spots left after a dog urinates on it, you would need to walk the dog somewhere else to do his or her business.
21. The final caller of the day has tomatoes that are growing well and they are now 3.5 feet tall, however, they have no blossoms on the plant. What would cause this?
A. This would be due to high Nitrogen levels in the soil. It cannot be fixed at this time, but don’t add any additional fertilizer to the garden for a couple of years to bring the level back down.