48 articles tagged "Crop Culture".

Bolting of crops overwintered in high tunnels is common in the spring. ‘Bolting’ refers to lengthening and blooming of the flowering stalk. Bolting is often a problem because the quality of the marketable part of the plant declines. Also, plants subject to bolting are programmed to die once they complete flowering and seed production so yield will decline in quantity as well as quality. Sometimes bolting is not a problem because the stalk, buds, and flowers can be sold as a new product while they last; this is often the case with kale,  mustards and related crops. Crops susceptible to bolting include those in the mustard family such as kale, mustards, tatsoi, bok choy (pac choi), mizuna, turnip, radish, etc.; carrots; beets and in some cases Swiss chard; onions; lettuce; and spinach. (Figure 1)   Bolting is triggered by environmental conditions. Some plant types are triggered to develop flowers by[Read More…]


Tomato and Cucumber growers who are interested in grafting tomato and cucumber plants by themselves may find this information helpful. Step-By-Step instruction of how to graft tomato plants is available from Purdue Extension publication Vegetable Grafting: Techniques for Tomato Grafting https://mdc.itap.purdue.edu/item.asp?Item_Number=HO-260-W as well as a Purdue Extension video https://www.youtube.com/watch?v=7Ufx66Isf88 A cucumber grafting instruction was also recently released. It provides step-by-step guidance of cucumber splice grafting technique. The publication is available at https://www.extension.purdue.edu/extmedia/HO/HO-328-W.PDF


Figure 2. A severe case of hollowheart watermelon.

Hollowheart of watermelons is a physiological fruit disorder. Flesh separates inside of the fruit, typically forming three gaps (Figure 1 and 2). In severe cases, hollowheart could cause watermelon load rejection. Watermelon fruit that has hollowheart tends to be triangular shaped. Poor pollination is the primary reason causing hollowheart. Scientists were able to prove that seedless watermelons are more likely to develop hollowheart when the pollenizer plants (diploid watermelons) are located further away from the seedless plants. The study found hollowheart incidence starts to increase when the distance between the seedless plant and the pollenizer plant is more than 6 feet. Cold weather and the lack of bee movement during pollination period causes poor pollination and increases the chance of hollowheart. Some growers use mixed pollenizer plants with different flowering peaks to ensure availability of pollen matching the blooming period of seedless plants. Bumblebees, in addition to honeybees, are sometimes used; bumblebees are relatively more[Read More…]


Figure 1. A server case of leaf burn under high temperatures.

Strawberries are primarily grown in the mattered row system in Indiana, in which bare-root strawberry plants are set in the spring, fruit is first harvested in the second year and plantings are renovated each year for a few seasons. Growers in southern Indiana have expressed interest in growing strawberries in the annual plasticultural system. With this annual system, plants are set in the fall and harvested in the spring of the following year. Plantings are not normally carried over a second year. Although the annual plasticultural system is very popular in the southern states, its usage is limited in Indiana mainly because our short fall weather conditions pose a challenge for strawberry plants to develop enough branch crowns, which allows them to achieve the optimal yield in the following spring. In the past two years, we have been testing the annual strawberry production system with additional protection from high tunnels[Read More…]


Watermelon harvest is in full swing in southern Indiana. At this time, we frequently see many types of leaf symptoms. Some of them are caused by foliar diseases, such as anthracnose, Alternaria leaf blight and gummy stem blight. These diseases require special attention, normally in the form of fungicide sprays, to slow spread of the disease. However, the appearance of a moderate amount of foliar disease in mid-season doesn’t necessarily need an immediate fungicide application. Other leaf symptoms may not be caused by diseases or insects. Here are some examples of leaf symptoms that are not associated with a pathogen. It is important to correctly identify the source of the symptom to prevent unnecessarily pesticide spray. In the article When a yellow leaf is just a yellow leaf, Dr. Dan Egel discussed general rules for determining if the symptom is a disease or not. If you are not certain whether the symptom[Read More…]


I have recently received a number of calls from growers about how to prune determinate tomatoes in a stake and weave system. Although this is relatively easy compared to how to prune indeterminate tomatoes with a trellis system, there are a few things I would like to call to your attention. What to prune  The common practice is to prune the suckers at the bottom of tomato plants. The benefit of this practice is to improve airflow which may help to control foliar diseases. Shoots of determinate tomatoes stop growing once they set a terminal bud. Most of us understand that if suckers are pruned too much, plants may have reduced yield.  However, there is confusion about exactly what to prune. Normally, the bottom 6-7 suckers should be pruned until the first flower cluster. But it is important to note that the sucker just below the first flower cluster develops a[Read More…]


Figure 1. Strawberries were covered with straw mulch and row cover. Picture were taken in Jan. 9 2018.

Although strawberry plants can be quite cold hardy, they need protection to survive the winter. In North Carolina, growers use floating row covers to protect strawberries in the winter. In Indiana, straw mulch is a more traditional way of winter protection for strawberries grown in a matted row system. After two relatively mild winters in 2015 and 2016, I heard successful stories about growing strawberries with the plasticulture system and using row covers for winter protection in Southern Indiana. Can the system also be successful in a colder winter, like the one that just passed? Our ongoing strawberry study will provide the answer. This article provides an update from this project comparing strawberries covered with straw mulch (about 4-inch thick) and row covers (two layers of 1.5-oz/yard2 row cover laid on wire hoops) this past winter (Figure 1). Temperature Between Dec. 27 to Jan. 6, we had the coldest nights[Read More…]


Figure 2. Plants died in the second day after average soil temperature was 54 °F

Growers start to plant tomatoes in unheated high tunnels around the end of March in southern Indiana. Around that time, there may still be a few light frosts, or even heavier ones, like the one we just experienced in the past week. With additional help from row covers inside of high tunnels, temperatures normally can be maintained above 32°F. Tomatoes typically do not have problems with the short-term low temperatures. However, this may not be the case for cucumbers. Although they are both warm season crops, Cucurbits (cucumbers, cantaloupes, and watermelons) are much more cold sensitive than Solanaceous crops (tomato, pepper). From a temperature perspective, this article discusses important considerations for deciding the time for planting cucumbers in a high tunnel. The best condition to grow cucumbers is when soil temperatures are above 70°F. This situation may not happen until the middle of May inside of the high tunnels, according to our[Read More…]


On January 1, products containing >6.5% dicamba and an agriculture use label are now restricted use pesticides. In order to purchase these herbicides, buyers must carry a private or commercial pesticide applicator license. While dicamba herbicides have been on the market for over 50 years to control broadleaf weeds, the recent development of dicamba resistant soybeans has given soybean producers a new post-emergent option for the management of herbicide resistant weeds. The new soybeans are XtendiMax® soybeans and FeXapan®, XtendiMax®, or Engenia® herbicides, all dicamba-based products can be sprayed on them. Those producers who plan to apply any of the three soybean dicamba products MUST attend a training before any of these products are applied. This is a requirement mandated by the EPA approved label. These trainings cover basic drift reduction techniques, as well as label requirements. One requirement is before application of a soybean dicamba product; producers must visit[Read More…]


A grafted tomato plant grown in a high tunnel

Awareness of tomato grafting has increased tremendously in the past years. Some growers fall in love with this technology and apply it to every tomato they grow. While others find this technology is not cost effective. The growers who have successfully adapted this technology are often small-scale, high tunnel or greenhouse growers who have mastered the grafting technique. They graft tomatoes by themselves and often can achieve a high survival rate. In this case, the added cost for grafted plants is mainly the cost of rootstock seeds, which is roughly 30-50 centers per plant. A small amount of yield increase could easily compensate for the added cost. This is particularly true for tomatoes grown in high tunnels that often sell at a higher price. In situations that farmers buy grafted plants, the cost rangs from $1 to $3 per plant. Farmers would expect a high percentage of yield increase to compensate for[Read More…]


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