42 articles tagged "Greenhouses & High Tunnels".

Figure 5: Tirreno, an Italian netted variety, orange flesh color

Indiana is a very important player in the domestic melon market. The total acreage planted in Indiana peaked in 1997 at 3,600 acres. In that year the total production was 455,000 cwt with an average income of $16.00 per cwt. The total farm value of production was $7,280,000 ($2,022 per acre). Yield has increased since 1997 from 130 cwt per acre to more than 200 cwt per acre in 2014. The Indiana melon growers have lost a significant share of the melon market since the 2011 and 2012 food borne illness outbreaks. Compared to 2011, the acreage planted and production in 2015 decreased by 900 acres and 52% (300,000 cwt), respectively. Quick Facts about Indiana Cantaloupe Transplant Production: March/April Planting Season: April – June Harvest Season: June – Sept. Plant Population (2.5 ft. x 6 ft.): 2,904 plants per acre Total acres planted: 2,100 acres (2013), 1,900 acres (2014), 1,800[Read More…]

Figure 1. A 30% black shade cloth was added to one of the high tunnels

We have discussed the pros and cons of using shade cloth for growing high tunnel tomatoes in this article https://vegcropshotline.org/article/whether-to-put-shade-cloth-on-high-tunnel-tomatoes/ Shade cloth helps with reducing temperatures inside the high tunnel. But it also reduces light intensity that is essential for photosynthesis. To better understand to what extent can temperature and light reduced with a shade cloth applied on top of a high tunnel, We did a comparison this summer at Southwest Purdue Agricultural Center, Vincennes, IN, with one high tunnel applied with 30% black shade cloth, and the adjacent one did not (Figure 1). The following figures (Figure 2 and 3) illustrate how temperature and light levels in the high tunnel were affected by the shade cloth in a typical sunny (July 23) and a cloudy day (July 2). On both days, about 10 degree difference of maximal temperatures were observed between the two tunnels. On the sunny day of July[Read More…]

Figure 2. Cowpea was worked into the soil

We have grown strawberries from Aug, 2015 to May, 2016 in one of our high tunnels at Southwest Purdue Agricultural Center. After taking the strawberry plants out of the high tunnel in the end of May, we did have enough time to grow a warm-season crop, like cucumbers. However, because for most of us June is such a busy time working in the field, we decided to put cover crops inside the high tunnel in the summer months and plant cool-season crops in the fall. Our primary goal of growing cover crops is to provide nitrogen for the following crops and increase soil organic matter. We decided to use a legume cover crop cowpea in this case because it has excellent drought and heat tolerance. Cowpea at a rate of 100 lbs per acre was sowed on June 17th. With the high temperatures inside the high tunnel, cowpea reached 30’’ high[Read More…]

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…]

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Driving across IN now, it is not uncommon to see many recently built high tunnels standing along the roadsides. These structures have become an important tool for farmers to extend production seasons of vegetable and fruit crops. Compared with traditional greenhouses, high tunnel demand much less energy as they are heated by solar energy and ventilated through natural air circulation. Similar to high tunnels, Chinese-style solar greenhouse is an important tool for season extension in specialty crop production in China. The structures are facing south, featured by supporting north walls (Figure 1 and 2). The north walls are essential in maintaining temperatures inside the structure. They are made up with materials having good insulation properties and with a thickness more than 30 inches. The south sides are arch-shaped, supported by steels and covered with polyethylene or polyvinyl chloride films. From north to south, the structures span 26-46 feet. A short[Read More…]

Figure 1. Hornworm feeding on tomato leaves in a high tunnel.

Hornworms can be pests of tomato and pepper in field grown crops, but for some reason seem to be particularly severe in high tunnels. Hornworms are very large caterpillars, measuring up to 4 inches long (Figure 1), and they can consume large quantities of foliage and will also feed on green fruit (Figure 2). In fields, hornworm damage is usually localized and tolerable, although treatment is sometimes required. In high tunnels, hornworm damage, particularly to tomato, is often severe (Figure 3) and will require several applications of insecticides. In field situations, the treatment threshold is one hornworm per two plants. Since the infestations are often localized, it may not be necessary to treat the entire field. In high tunnels, there is no established threshold, so my recommendation would be to treat as soon as you seen caterpillars or their damage. The good news is that hornworms are fairly easy to control.[Read More…]

Figure 1. A ladybug feeding on aphids

Supplementing the natural enemy population to control insect pests, i.e. augmentation biological control, is of interest to many high tunnel producers. Augmentation biological control has proven very effective at managing a number of greenhouse pests and there are a variety of commercial suppliers. For high tunnels, the greatest challenge is keeping the released predators or parasitoids inside the tunnels and choosing agents that are effective under high temperatures, during the peak of the growing season. We have evaluated some of the more common control agents in high tunnel cucumber and tomato production. The convergent ladybug, Hippodamia convergens, is not grown in a growth facility but rather caught in the wild in the western U.S. (typically California) and shipped throughout the US for control of aphids in particular. They are a fairly inexpensive predator (1500 for about $15.00), the immature form (larvae) and adults feed on aphids (Figure 1). However, you[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 1. Aphids on tomatoes in a high tunnel (Photo credit Wenjing Guan)

We have begun to receive the first reports of aphid outbreaks in high tunnels on tomato, pepper, and cucumber (Figure 1). Aphids are a very common problem in high tunnels because the covering excludes rainfall, which is a major mortality factor for small insects like aphids. Some growers are interested in using biological control in their high tunnels because the ability to contain natural enemies within the tunnels increases the likelihood of achieving control. Based on our experience, we believe that lacewing larvae hold the greatest promise for successful biological control of aphids in high tunnels. Because they don’t fly, they are less likely to leave the high tunnel than many other biological control agents. There are a number of biological control suppliers who can provide lacewing larvae for growers. For growers interested in chemical control, some of the insecticides that could be expected to provide good control and are[Read More…]

I have observed leaf mold of tomato in greenhouses and high tunnels recently. This article will discuss this disease and management options. In the last issue of the Hotline, I discussed Botrytis gray mold. I noted how gray mold is favored by the cool, cloudy weather we experienced earlier this spring. The warmer and sunnier weather we have experienced more recently should favor leaf mold over gray mold. Leaf mold is caused by the fungus Passalora fulva. Cercospora leaf mold of tomato is rare in Indiana and is discussed here (https://vegcropshotline.org/article/cercospora-leaf-mold-of-tomato/). The first symptom of leaf mold one is likely to notice is a pale yellow lesion on the top side of the leaf (Figure 1). When the leaves are turned over, the fungal mold that gives the disease its name becomes evident (Figure 2). Leaf mold often becomes a problem under humid conditions (85% humidity or greater) and temperatures between 71 and 75°F, although leaf[Read More…]

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