55 articles tagged "Crop Culture".

The 2019 production season started with above-normal rains. The wet conditions affected agriculture production, including watermelon and cantaloupe. In this article, we will review some of the watermelon and cantaloupe problems that are often associated with wet conditions. Manganese toxicity– This nutrient disorder occurs more often on cantaloupe that is grown in soils with pH lower than 5.5. Although liming before planting is a common practice, it is not unusual that we see soil pH that has dropped below 5.5 in sandy soil, especially during wet years. Manganese exists in soil solution as either reduced (Mn2+) or oxidized (Mn3+) form. Plants take up manganese in the reduced form (Mn2+). The proportion of exchangeable Mn2+ increases dramatically as soil pH decreases, and this reaction is promoted in waterlogged soils with low oxygen condition. As raindrops fall through the air, they dissolve CO2 and form enough carbonic acid to lower the pH of[Read More…]


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The wet spring has likely delayed some planting of pumpkins. What does delayed planting mean for yield? Data and observations from Purdue Ag Centers offer some perspective to supplement other experience. Figure 1 shows how pumpkin yield was affected by planting date for 6 trials. Each line represents a different trial. The Y-axis shows relative yield within in each trial. Yield of the first planting date for each trial is set to 100. For the two trials at Pinney Purdue (orange lines, PP2002 and PP2003), pumpkins seeded June 20-25 yielded 70%-85% of pumpkins seeded by early June. In the 1995-1996 trials at Southwest Purdue Ag Center (light green lines, SW1995 and SW1996), pumpkins transplanted June 25-30 produced about 50% of those transplanted two weeks earlier (June 10-15). Transplanting two weeks later (July 10-15) produced only 30% of the yield compared to the June 10-15 plantings. In the 1997-1998 trials at[Read More…]


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Finally the time has come to plant warm season crops. Zucchini is a popular summer squash grown throughout Indiana and the United States. It always delivers a bounty of fruit. Yes, technically zucchini is a fruit (botanically classified as a modified berry) but as per the USDA it is listed under the ‘Vegetables and Vegetable Products” food group. Zucchini have a multitude of fruit colors and flavors. Therefore, this makes a great vegetable to present to consumers. Characteristics of zucchini – Typically, zucchini is non-vining and bushy but some varieties could have a creeping habit. Some varieties have prickly trichomes on both the stems and leaves. Male and female reproductive structures are produced on the same plant but in different flowers. The large yellow-orange unisexual flowers (a flower that possesses either stamens or carpels but not both) attracts bees, beetles and other insects to pollinate the flowers. The pollen is[Read More…]


Figure 2: Eight day-neutral stawberry cultivars grown under retractable low tunnel systems (picture was taken on May 20)

With the support of the Purdue Extension AgSeed Program, we are currently evaluating different production systems for growing strawberries in an open-field with plastic cultural systems for our area at Southwest Purdue Agricultural Center in Vincennes, IN. A day-neutral strawberry cultivar evaluation trial was established in the Spring of 2019. The evaluated cultivars include Portola, Evie-2, Mara Des Bois, Albion, Seascape, San Andreas, Monterey, and Tribute. Bare-root plants purchased from Nourse Farm and Indiana Berry were planted on black plastic mulch on Mar. 22. Cultivar Portola was planted on Apr. 10 due to back-order. Each of the eight cultivars were grown either with a retractable low tunnel system or without it (Figure 1). Although strawberries were planted this spring, most cultivars started to bloom toward the end of April. Removing runners started in early May. During the week of May 13, harvest started on the early cultivars: Tribute, Mara Des[Read More…]


Figure 4. Connect four stakes in a rectangle shape (A), cross the hook (12’’) with the central-string (B) and hook it to the side-strings between the two tomato plants (C).

The Florida-weave or sometimes called stake and weave is a commonly used tomato trellis system (Figure 1). It has several benefits and is easy to implement. However, sometimes the plants grow too tall and can hardly be supported by the stakes, or they may be too vigorous and break the strings. In this article, we will introduce an alternative tomato trellis system, Spanish-weave, and discuss its usage in tomato production. How to trellis tomato plants with the Spanish-weave system? Materials: tomato stakes, tomato strings, and hooks. We made the hooks from steel wire. They were made at 4-inch, 8-inch and 12-inch length (Figure 2). Prune bottom leaves of the tomato plant and suckers until the first flower cluster (Figure 3). Install tomato stakes on each side of the rows at every two tomato plants (A); Tie strings across the two wooden stakes at the beginning and the end of each[Read More…]


Two types of injury on young warm-season vegetable plants are caused by low temperatures: frost/freezing injury and chilling injury. Frost/freezing injury occurs when temperatures drop below 32°F. Ice formation in plant tissues cut cell membranes. When the tissue thaws, the damage results in fluids leaking from the cell, causing water soaked damage. Frost/freezing injury is detrimental to warm-season vegetables, such as melons, cucumbers, tomatoes, peppers, beans. To avoid damage, the best way is to plant warm-season vegetables later in the spring, after the last frost has passed. However, weather is difficult to predict, and there is a growing trend of planting early to achieve early harvests. For the early planted warm-season vegetables, here are a few suggestions that may protect plants from low temperature damages. Covering. The idea of covering the seedlings is to create a microclimate around plants. Because the heat accumulated in soil irradiate back at night, covering[Read More…]


Figure 1. Cucumbers start to wilt following a night average soil temperature was 58 °F

Chilling injury occurs when temperatures are above 32°F and below 55°F. The plant tissue becomes weakened that leads to cellular dysfunction. The most noticeable visual symptom of chilling injury is leaf and hypocotyl wilt (Figure 1). This is caused by the rapid decline in the ability of roots to absorb and transport water. It also caused by the plant’s reduced ability to close stomata. If temperatures do not improve, plants may be killed. Low temperatures also have an effect on mineral nutrient uptake of the plants. Absorption of ions by roots is difficult, as well as their movement in the above-ground parts of the plants. As a result, chilling injured plants often show symptoms similar to nutritional deficiency. Although warm-season vegetables are all susceptible to frost/freezing damage, their susceptibility to chilling injury varies among plant species. Pepper plants seem to have greater difficulty recovering after chilling injury compared to tomato[Read More…]


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…]


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