Video of the Week:
Common Tomato Problems
Vegetables:
Pulling Onions
Onions are ready to harvest when about half the plants have tops that have fallen over. This is a sign that the onions are mature and need to be pulled out of the ground. Bulbs may sunburn without the foliage to protect them. The secret to onions keeping well is to allow the tops to dry completely before storage. Move onions to a shaded, well-ventilated area after harvest. After tops are completely dry, store in a cool, dry location. Large-necked onions take more time to dry than small-necked onions such as Bermuda types. Avoid storage in plastic bags because the lack of air circulation will shorten storage life. Use an open, mesh bag instead. (Ward Upham)
Harvesting Potatoes
Potatoes are ready to harvest when the vines are about half dead. Potatoes dug too early have tender skins and are easily bruised. Delaying digging will allow the soil to heat because it is no longer shaded by foliage. High soil temperatures can lead to sprouting potatoes. Allow potatoes to "set" by keeping them in a shady, dry location for a day or so. Move them to a cool, moist environment such as a cellar or cool basement for longer storage. (Ward Upham)
Bumps on Tomato Stems
Tomato stems sometimes develop “warts” or “bumps” on the stems close to ground level. Though this looks abnormal, the condition is natural and not harmful.
These bumps can eventually give rise to roots (called adventitious roots) if conditions are favorable. This is actually the mechanism the plant uses to form roots when tall, leggy plants are planted in a trench. Some varieties tend to be more prone to this condition than others and stress such as that produced by waterlogged soils also makes a “warty” stem more likely. Growth regulator type herbicides such as 2,4-D can also induce this state. So if you see a warty stem, don’t be concerned. The bumps will not harm the plant in the least. (Ward Upham)
These bumps can eventually give rise to roots (called adventitious roots) if conditions are favorable. This is actually the mechanism the plant uses to form roots when tall, leggy plants are planted in a trench. Some varieties tend to be more prone to this condition than others and stress such as that produced by waterlogged soils also makes a “warty” stem more likely. Growth regulator type herbicides such as 2,4-D can also induce this state. So if you see a warty stem, don’t be concerned. The bumps will not harm the plant in the least. (Ward Upham)
Pests:
Sweet Corn Earworm
Corn earworm tends to be a problem every year on sweet corn in Kansas. The earworm moth lays eggs on developing silks at night. When the egg hatches, the larva crawls down the silk and into the ear. Feeding starts at the tip of the ear and works down. Though several earworms may hatch and attack a single ear, only one is usually present at harvest
Control is challenging as silks continue to grow over a period of time. This means that even if silks are treated, new silk will appear that hasn't been protected. Applications every 2 to 3 days are needed for insecticides to be effective, especially in late June to early July when peak flight of these moths usually appear.
There is a three-week period from silking to harvest, but there is only a two-week period from when the silks appear to when they begin to dry. Since moths prefer juicy silks and shun those that have started to dry, insecticides are only needed the first two weeks of silking.
Homeowners can use cyfluthrin (Baythroid; Bayer Powerforce Multi-Insect Killer) or spinosad (SpinTor; Captain Jack's Dead Bug Brew; Conserve; Borer, Bagworm, Tent Caterpillar & Leafminer Spray). Spinosad is an organic product. Commercial growers have additional choices including zeta-cypermethrin (Mustang Max), bifenthrin+zeta-cypermethrin (Hero), spinetoram (Radiant) and flubendiamide (Belt).
Though more time consuming, mineral or other light horticultural oils may also be used. The oil is placed inside the silk end of the ear with a medicine dropper (½ to 3/4 of a dropper) after the silks brown. This will coat the earworms already present and likely suffocate them, though some damage to the tip of the ear will likely have occurred. Applying the oil before the silk has browned may interfere with pollination, leading to incompletely filled ears. (Ward Upham)
Control is challenging as silks continue to grow over a period of time. This means that even if silks are treated, new silk will appear that hasn't been protected. Applications every 2 to 3 days are needed for insecticides to be effective, especially in late June to early July when peak flight of these moths usually appear.
There is a three-week period from silking to harvest, but there is only a two-week period from when the silks appear to when they begin to dry. Since moths prefer juicy silks and shun those that have started to dry, insecticides are only needed the first two weeks of silking.
Homeowners can use cyfluthrin (Baythroid; Bayer Powerforce Multi-Insect Killer) or spinosad (SpinTor; Captain Jack's Dead Bug Brew; Conserve; Borer, Bagworm, Tent Caterpillar & Leafminer Spray). Spinosad is an organic product. Commercial growers have additional choices including zeta-cypermethrin (Mustang Max), bifenthrin+zeta-cypermethrin (Hero), spinetoram (Radiant) and flubendiamide (Belt).
Though more time consuming, mineral or other light horticultural oils may also be used. The oil is placed inside the silk end of the ear with a medicine dropper (½ to 3/4 of a dropper) after the silks brown. This will coat the earworms already present and likely suffocate them, though some damage to the tip of the ear will likely have occurred. Applying the oil before the silk has browned may interfere with pollination, leading to incompletely filled ears. (Ward Upham)
Grub Control
If you plan on using a grub preventative on your lawn, the first half of July is a good target date for most products. Preventatives are normally used on areas that have had a history of grub problems. Traditional grub insecticides such as Dylox orcarbaryl (Sevin) are normally applied in late July after grubs are present or as a rescue treatment once damage is seen. Products that contain Merit (imidacloprid) are considered grub preventers. Actually, neither product prevents grubs, but rather they kill grubs when they are quite small, and long before they cause damage. Merit is safer to use around pets and humans than traditional grub killers. Merit can be found in Bayer's Season-Long Grub Control, Grub No-More, and Grub Free Zone.
Another grub preventer with the trade name GrubEx contains chlorantraniliprole. Though this product is very effective, it is less water soluble than imidacloprid. It should be applied earlier, preferably April or May, but applications through June should still be effective. Remember, all grub products should be watered in soon after application. (Ward Upham)
Another grub preventer with the trade name GrubEx contains chlorantraniliprole. Though this product is very effective, it is less water soluble than imidacloprid. It should be applied earlier, preferably April or May, but applications through June should still be effective. Remember, all grub products should be watered in soon after application. (Ward Upham)
Miscellaneous:
Checking for a Healthy Root System in a Potted Plant
What a foundation is to a house, so a root system is to a plant. Yet the root system is often overlooked even when it is easy to check as with potted plants. So how do you check the root system of a potted plant? The first step is to knock the plant out of the pot.
Place your hand over the top of the pot with the stem of the plant passing between two of your fingers. Turn the pot upside down and tap the edge of the pot against the edge of a table, counter or other hard surface. The plant should release and come out.
A healthy root system will typically have white roots or at least roots with white tips. The roots should be visible along the outside of the rootball and should reach the bottom of the pot. Unhealthy roots will be blackened and may have a slimy appearance and foul smell. Also, an unhealthy root system often does not reach the bottom of the pot. By far the most common cause of an unhealthy root system is overwatering.
Water by touch, not by calendar. If the soil is dry an inch deep, it is time to water. An alternative method is to water by weight, if practical. Lift the pot after a good, deep watering to determine the weight of the well-watered plant. Then use the “dry an inch deep” method to determine when it is time to water. Check the weight of the plant at that time. This will give you an idea of the difference between a well-watered plant and one that is ready for more water. The time between waterings will vary tremendously between summer with its long days and active plant growth and winter with cooler days, shorter days and little to no growth.
Be sure to add enough so that some water flows out the bottom of the pot. This will help wash out excess salts that tend to accumulate within the potting soil.
Contributors: Ward Upham, Extension Associate
Place your hand over the top of the pot with the stem of the plant passing between two of your fingers. Turn the pot upside down and tap the edge of the pot against the edge of a table, counter or other hard surface. The plant should release and come out.
A healthy root system will typically have white roots or at least roots with white tips. The roots should be visible along the outside of the rootball and should reach the bottom of the pot. Unhealthy roots will be blackened and may have a slimy appearance and foul smell. Also, an unhealthy root system often does not reach the bottom of the pot. By far the most common cause of an unhealthy root system is overwatering.
Water by touch, not by calendar. If the soil is dry an inch deep, it is time to water. An alternative method is to water by weight, if practical. Lift the pot after a good, deep watering to determine the weight of the well-watered plant. Then use the “dry an inch deep” method to determine when it is time to water. Check the weight of the plant at that time. This will give you an idea of the difference between a well-watered plant and one that is ready for more water. The time between waterings will vary tremendously between summer with its long days and active plant growth and winter with cooler days, shorter days and little to no growth.
Be sure to add enough so that some water flows out the bottom of the pot. This will help wash out excess salts that tend to accumulate within the potting soil.
Contributors: Ward Upham, Extension Associate
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