40 articles tagged "Crop Culture".

Figure 1. Strawberries grown inside a high tunnel at Southwest Purdue Agricultural Center. Photo was taken on April 16 2016.

We are familiar with strawberries grown as a perennial crop in Indiana. Bare root strawberry plants are set in the spring. Fruit is first harvested in the second year and the planting is renovated annually. Using this system, strawberry seasons last for three to four weeks from middle May through June. The traditional system has been replaced with an annual plasticulture system in the southern United States ever since the 1980s. In the annual plasticulture system, strawberry plugs (rooted runner tips) are transplanted in plastic covered beds in late summer or fall. Fruit are harvested in spring in the next year. After the fruiting season, the plants are removed. The annual plasticulture system is favored in the south because it has a longer harvest period and produces strawberries with better quality. In Indiana, trials established to test the annual plasticulture system had limited success because of short fall season and harsh[Read More…]

Last week, the highest temperature reached 110°F for a few successive days inside of our high tunnels. As a result, we observed some blossom drop on tomatoes. More information on high temperature effects on tomato fruit set can be found here. In addition to blossom drop, high temperature and high light intensity contribute to sunscald injury, uneven ripening, and cracking of tomato fruit. To protect tomatoes from damage caused by excessive heat, we placed 30% black shade cloth on top of the high tunnel. By installing the shadecloth, we expect there will be less cracking and more uniformly ripe tomatoes. Tomato marketability will increase. However, using shade cloth also has some negative effects. In this article, we review the effects of high temperatures on tomatoes, and discuss positive and negative aspects of using a shade cloth. Excessive high temperature (above 100°F) lasting for a few hours for successive days could cause tomato flower abortion and affect[Read More…]

Figure 2. Wilt cucumber plants in a high tunnel

  Last week, we were called by a few watermelon growers who reported their newly planted watermelon seedlings were dead (Figure 1 ). After closely inspecting the affected plants, we did not find any pathogens. This reminded us of what happened to our cucumbers back in early April in our high tunnel. We will review the cucumber story first, and rethink what might have happened to the watermelons. Cucumbers were planted on March 30 in a high tunnel located at Southwest PurdueAgricultural Center (SWPAC), Vincennes, IN. The lowest air temperature after planting was recorded at 37.5°F inside the high tunnel, which should not be low enough to cause frost damage. However, we lost 40% to 80% of the newly planted cucumbers depending on varieties. The symptoms were similar to water deficiency-caused plant wilt (Figure 2 ). Most of the dead plants had intact stems, however, we did find wire worms[Read More…]

Planting density plays an important role in the optimization of labor efficiency and productivity of your high tunnel. For the purpose of this article I will focus on tomato which is commonly grown as a high value crop on small farming operations. Usually growers select varieties according to customer (market) preference and then try to combine that with other attributes such as ease of production, disease tolerance/resistance and productivity (yield). Consumer preference usually helps to determine the fruit color, size and shape, and the sweetness (soluble solids) of the tomato variety to be grown. The grower again is interested in earliness, growth habit (determinate and indeterminate), and ease of pruning, trellising and picking. Most growers in Indiana choose determinate varieties for high tunnel production, because it has limited growth and is easy to stake and allows for early production (short production cycle), with most fruit ripening before field grown tomatoes[Read More…]

Every year since 1980, we have conducted watermelon and cantaloupe variety trials at Southwest Purdue Agricultural Center. In 2016, our variety trials include 44 standard seedless watermelons, 12 cantaloupes, 4 mini-sized seedless watermelons, and 5 seeded watermelon varieties. Seeds have already been planted in the greenhouses and our target date for transplanting in the field will be the week of May 9th. The fruit will become ripe around the middle of July. If you are interested in observing how each variety performs during the season, don’t hesitate to come to visit us and witness the plots first hand. We will continue to present the results of our variety trials, as in the past, at the annual meeting held at the Southwest Purdue Ag Center in late November or early December but don’t miss the opportunity to visualize them during the growing season. In the winter meeting, we will discuss yield[Read More…]

Lettuce is grown in channels using the Nutrient Film Technique

Travelling through Indiana last summer, I realized that many growers plant their crops in soil inside their high tunnels or greenhouses. Soilless production offers different benefits and challenges. This is the first article in a series focusing on soilless crop production in high tunnels and greenhouses. Today we are discussing Hydroponics. What is Hydroponics?  The word hydroponics technically means ‘working water’, derived from the Latin words “hydro” meaning water and “ponos” meaning labor. Hydroponics is a method to grow plants using a mineral nutrient solution, in water and without soil. Two types of hydroponics are commonly found: a) solution culture, and b) medium culture. Solution culture types include continuous flow solution culture (Nutrient Film Technique) and Aeroponics. Medium culture types include ebb and flow sub-irrigation, run to waste, deep water culture and passive sub-irrigation systems. History.  The first research published on the production of spearmint in water was conducted by[Read More…]

Tomatoes grown in controlled environment are exposed to conditions that are different from their original habitats. As a result, varieties that are not specifically bred for greenhouse production may respond to the controlled environment with abnormal symptoms. One group of the symptoms is called edema. Bumps, galls or blisters develop on tomato leaves, petioles or stems (Figure 1). In severe conditions, it causes leaf curling, distortion and abscission (Figure 2). A couple of factors including high humidity, excessive water in the soil, air pollution, and low light condition could cause the symptom. Tomato varieties respond differently in susceptibility to the physiological disorder, and the primary contributing factors can also be different among tomato varieties. The most severe case of edema that we have observed so far is on tomato rootstocks including ‘Maxifort’. This is not surprising as most of the commercial tomato rootstocks are hybrid of wild tomatoes Lycopersicon esculentum[Read More…]

​Crop production, decomposition of organic matter, using ammonium-producing nitrogen fertilizers, and rainfall all lower soil pH. To maintain soil pH in the optimal range (6.5 to 6.8) for vegetable production, periodic application of lime is needed. The primary form of agricultural lime is calcium carbonate (CaCO3). It is the carbonate (CO3^2-) part that brings up soil pH. Whenever lime is applied, a large amount of calcium is also added to the soil. The good news is that calcium is an essential plant nutrient. Several vegetable problems that we are familiar with are caused by calcium deficiency for example, blossom end rot of tomatoes and peppers, and tip burn of cabbages. However, it should be noted that excess calcium might interfere with plant available magnesium and potassium. Therefore, it is always better to keep a balance of those nutrients. Some lime products are specified as dolomitic lime. Dolomitic lime is common[Read More…]

Vegetables such as this watermelon may become sunburned if lack of foliage cover exposes the fruit to excess sun and heat. (Photo by Dan Egel)

​Loss of foliage due to poor growing conditions or disease can cause fruit to be exposed to the sun. Hot temperatures and direct sunlight can lead to areas of the fruit that appear bleached or sunburned. Sunburned fruit may not be marketable. To reduce the probability sunburned fruit, every effort should be made to maintain foliage throughout the season. Early wet weather encouraged foliar disease and recent hot, dry weather may have restricted foliar development. Orienting vegetable plantings to minimize damage from the prevailing winds and providing windbreaks such as strips of rye or wheat may help to reduce sunburn. Several products are available that are labeled for use as a preventive for sunburn. These products may be broken into two groups: kaolin (clay) based products and calcium carbonated based products. Kaolin based products include Surround®. Some Surround® products are labeled for use as sunburn protection, while others are not. For example,[Read More…]

​Growers may be wondering whether to replant pumpkin fields where the stand is uneven due to excess moisture. Potential yield of the replants is one thing it would be good to know. We have data on yield of pumpkins direct-seeded or transplanted in mid-July in northern Indiana. The trials were no-till planted into a harvested wheat field. Pumpkins were harvested in mid to late October. Yield of direct-seeded pumpkins ranged from 0 to 0.6 tons per acre for 8 varieties in 2004, and from 2.6 to 6.4 tons per acre for 5 varieties in 2005. Yield of transplanted pumpkins ranged from 2 to 8 tons per acre for 8 varieties in 2004 and from 4.4 to 9 tons per acre for 5 varieties in 2005. For comparison, typical yields at this site for an early- to mid-June planting date with conventional tillage range from 10 to 25 tons per acre.[Read More…]

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