Horticulture 2020 Newsletter
No. 28 July 14, 2020
Reminders
- Tomatoes can be harvested when they are green and red to prevent sunscald and to allow the development of a deeper red color during hot weather. The fruit will have the same quality as if it were vine ripened if allowed to ripen inside.
- Can plant potatoes if you have a source of seed potatoes.
- Can plant cabbage, broccoli and cauliflower from seed to be transplanted later
VEGETABLES
Tomato Cracking
Tomatoes often have problems with cracking caused by pressure inside the fruit that is more than the skin can handle. Cracks are usually on the upper part of the fruit and can be concentric (in concentric circles around the stem) or radial (radiating downward from the stem). We don’t know everything about cracking but here is what we do know.
Tomatoes have a root system that is very dense and fibrous and is quite efficient in picking up water. Unfortunately, the root system can become unbalanced with the top of the plant. Early in the season it may be small in relation to the top growth resulting in blossom-end rot when the weather turns hot and dry. Later it may be so efficient that it provides too much water when we get rain or irrigate heavily after a dry spell. This quick influx of water can cause the tomato fruit to crack. Therefore, even, consistent watering can help with cracking. Mulching will also help because it moderates moisture levels in the soil. However, you can do everything right and still have problems with cracking in some years.
We have evaluated varieties for cracking during our tomato trials at K-State. It takes several years worth of data to get a good feel for crack-resistant varieties but we have found some real differences. Some varieties crack under about any condition and others are much more resistant. The difference seems to be pliability of skin rather than thickness — the more pliable the skin the more resistance to cracking.
The old variety Jet Star has been the most crack resistant of any we have tested including the newer types. Unfortunately, Jet Star is an indeterminate variety that puts out rampant growth.
Newer varieties with more controlled growth are often more attractive to gardeners. Mountain Spring, Mountain Pride, Mountain Fresh, Floralina and Sun Leaper are smaller-vined types that have shown good resistance to cracking. (Ward Upham)
How to Pick a Ripe Melon
Telling when a melon is ready to be harvested can be a challenge, or it may be quite easy. It all depends on the type of melon. Let’s start with the easy one. Muskmelons are one of those crops that tell you when they are ready to be picked. This can be of help to not only harvest melons at the correct time but also choose good melons when shopping. As a melon ripens, a layer of cells around the stem softens so the melon detaches easily from the vine. This is called “slipping” and will leave a dish-shaped scar at the point of stem attachment. When harvesting melons, put a little pressure where the vine attaches to the fruit. If ripe, it will release or “slip.”
When choosing a melon from those that have already been harvested, look for a clean, dish-shaped scar. Also, ripe melons have a pleasant, musky aroma if the melons are at room temperature (not refrigerated).
Watermelons can be more difficult and growers often use several techniques to tell when to harvest.
- Look for the tendril that attaches at the same point as the melon to dry and turn brown. On some varieties this will need to be completely dried before the watermelon is ripe. On others it will only need to be in the process of turning brown.
- The surface of a ripening melon develops a surface roughness (sometimes called “sugar bumps”) near the base of the fruit.
- Ripe watermelons normally develop a yellow color on the “ground spot” when ripe. This is the area of the melon that contacts the ground.
Honeydew melons are the most difficult to tell when they are ripe because they do not “slip” like muskmelons. Actually, there is one variety that does slip called Earlidew, but it is the exception to the rule. Ripe honeydew melons become soft on the flower end of the fruit. The “flower end” is the end opposite where the stem attaches. Also, honeydews should change to a light or yellowish color when ripe, but this varies with variety. (Ward Upham)
FRUIT
Green June Beetle
These large beetles feed on sweet corn, blackberries, and peaches. They look much like the common May beetle, or June bug, but have a dull, velvety green color. The underside is more of an iridescent green. These beetles have poor navigational skills and seem to fly until they hit something. They also make a buzzing sound somewhaWhent like a bumblebee. Unfortunately, they are also about the size of a bumblebee and so cause concern for many gardeners even though they cannot harm people. As noted above, they may damage crops.
A number of general-use insecticides, including acetamiprid (Ortho Flower, Fruit & Vegetable Insect Killer), carbaryl (Sevin) and malathion, may be used to discourage feeding. See table below for what can be used and the number of days between application and harvest.
| Insecticide | Peaches | Blackberries, raspberries | Sweet Corn |
| Carbaryl* | 3** | 7 | 2 |
| Malathion | 7 | 1 | ——– |
| Acetamiprid | 7 | 1 | ——- |
* Carbaryl is found in Sevin Ready to Use and Sevin Dust but not in Sevin Ready to Spray or Sevin Concentrate.
** Days to harvest
Carbaryl has a two-day waiting period between spraying and harvest on sweet corn and a three-day waiting period on peaches. There is a seven-day waiting period for Sevin on blackberries, so malathion, with a one-day waiting period, may be a better choice. Acetamiprid has a 7 day waiting period on peaches and a 1 day waiting period on blackberries and raspberries. (Ward Upham)
Raspberries and Blackberries After Harvest
Raspberries and blackberries are perennial plants with biennial canes. What that means is that though the plants live year after year, each individual cane only lives two years. Most commonly the first year canes, referred to as primocanes, grow but don’t fruit. Primocanes become floricanes the second year. Floricanes fruit and then die.
So what do you do with these dead canes when they die after fruiting? Though many gardeners leave the canes for removal the following spring, it is best to remove them immediately after they die if your plants have had problems with disease such as anthracnose. See https://ohioline.osu.edu/factsheet/plpath-fru-27 . Remove the canes as close to the ground as possible without damaging the primocanes. It is best to discard, burn or bury any infected canes. (Ward Upham)
Netting Grapes
If you have grown grapes before, you have likely discovered that birds like grapes as much as you do. There are two methods homeowners can use to protect the fruit. The first is bagging where a paper bag is placed over the cluster and secured with a twist tie or staple. The bag can be left until it is time for harvest as flavor and color are determined by sunlight hitting the leaves rather than the cluster.
The second method is to net the crop. The most common and least expensive netting is the lightweight, black, polypropylene type with a square mesh size of ” x ”. This can be difficult to install and remove as it tends to stick to itself and to the vines. However, it is effective. Woven mesh bird netting is also effective and easier to work with but is more expensive.
If your trellis has a wire at six feet high, purchase a net that is at least 14 feet wide so that it can be draped over the grapes and secured along the bottom edge with clothes pins. Nets that are 17 feet wide are less common but give more material to work with and are therefore easier to secure. (Ward Upham)
Tan or White Drupelets on Blackberry and Raspberry Fruit
Blackberry and raspberry fruit will often develop white or tan drupelets on the berry. Though we are not completely sure of the cause in all cases, two commonly given reasons are stinkbug damage and sunscald. Damage has been attributed to stinkbugs if the pattern of off color (not white) drupelets is random. Stinkbug damage is caused by the insect feeding on the blackberry receptacle and injuring drupelets on either side. Damaged drupelets are often scattered. Sunscald damage will be on the side of the fruit exposed to the sun and has several to many drupelets in an area being affected.
Neither condition affects the eating quality of the fruit unless the stink bug releases the “stink” with which it is associated rendering the fruit inedible. By the time damage is seen, it is too late for control. (Ward Upham)
PESTS
Budworms on Garden Plants
If you have noticed a small hole in the buds of some of your flowers, you may have tobacco (geranium) budworm (Helicoverpa virescens). Though a number of flowers can serve as hosts, geraniums and petunias are most commonly attacked. The larva of this insect damages the buds by boring into them before they open. The caterpillars feed on the flowers for about a month and then drop to the soil to pupate. There are normally two generations per year, with the second causing the most harm. The striped caterpillars vary widely in color with green, red, light brown and dark forms possible. The color of the larva is related to the color of the flowers on which they feed. The adult of this insect is a moth.
Damaged buds often fail to open. Those that do will show evidence of feeding on the blackberry receptacle and injuring drupelets on either side. Damaged drupelets are often scattered. Sunscald damage will be on the side of the fruit exposed to the sun and has several to many drupelets in an area being affected.
Neither condition affects the eating quality of the fruit unless the stink bug releases the “stink” with which it is associated rendering the fruit inedible. By the time damage is seen, it is too late for control. (Ward Upham)
Spider Mites
Most spider mites like summer weather. Look for stippling on the upper surface of the leaves as well as some fine webbing on the underside of the leaves. These tiny arthropods (they are not true insects) are often difficult to see due to their size and their habit of feeding on the underside of leaves. If mites are suspected, hold a sheet of white paper beneath a leaf and tap the leaf. Mites will be dislodged and can be seen as tiny specks on the paper that move about.
Spider mite control can be challenging. A strong jet of water can be used to remove the mites but may not be as easy as it sounds. A high-pressure directed spray is needed to dislodge the mites. Since spider mites feed on the underside of the leaves, the spray is most effective if it comes from below. This can be difficult to accomplish with a thumb over the end of the hose.
Some gardeners use a water wand hooked to a shut-off valve. The water breaker is then replaced by a brass nozzle. Specialized spray wands can also be used. For example, Mite-Y-Fine (miteyfine.com) has a wand that makes spraying the underside of leaves easy. Spraying once will not be enough. It is recommended to use 3 sprays spaced 3 to 4 days apart.
Horticultural oils and insecticidal soaps (Safers, for example) can also be helpful. Spray early in the morning when temperatures are cooler and plants have rehydrated. Resprays will likely be needed. (Ward Upham)
Contributors: Ward Upham, Extension Associate
Division of Horticulture
1712 Claflin, 2021 Throckmorton
Manhattan, KS 66506
(785) 532-6173
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Cooperating, Ernie Minton, Dean.
Ward Upham
Extension Associate
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Video of the Week: When to Pick Tomatoes
https://kansashealthyyards.org/all-videos/video/when-to-pick-tomatoes
