Wednesday, July 04, 2012

High Tunnel Crop Talk Notes July 2, 2012

High Tunnel Crop Talk Notes July 2, 2012

Summary: Hot and dry conditions have prevailed in the region over the last two weeks until storms over the past weekend. High winds from those storms have damaged tunnels in some areas. Yield and eating quality of tomatoes from high tunnels have been good this year, and demand and prices have been good. Tomato harvest in tunnels will be ending in July for many growers who will be moving to harvest field tomatoes. 

Join us again on July 16, 2012. 12:30 - 1:30 p.m. Eastern/11:30 - 12:30 Central. Point your web browser to and click on the phone icon to be dialed in to the call. Or participate without a computer by dialing 1-866-492-6283. 

Throckmorton PAC, Meigs Horticulture Research Facility: In the experiment to look at how fertility amendments mineralize, sweet peppers transplanted May 3  have been doing well the last month. They are starting to get mature fruit. 
Overview of peppers in high tunnel.
 Photo by Matt Rudisill.
Pepper fruit. 
Photo by Matt Rudisill.    
The treatments with fertilizer are doing pretty well. There are some observable differences in numbers and size of fruit between fertilizer treatments. Leaf greenness measurements have shown no differences yet. Blossom end rot is occurring in one replication of the composted chicken manure treatment. (Matt Rudisill)
Blossom end rot on pepper fruit.
Photo by Matt Rudisill.  
Blossom end rot beginning on pepper fruit. 
Photo by Matt Rudisill.
Question: Has crown fruit been pruned? Often in greenhouse pepper production crown flowers are removed because if left to develop those fruit often become wedged in between branches and are misshapen and unmarketable. Answer: No. 
Question: How much hotter in the tunnel than outside has it been? Answer: Last week it was 100°F outside and 105°F in the tunnel. Roll-up sides have been open all the way and upper vents have also been open.
Question: What is the plant spacing? Answer: Two feet apart in rows, about 1 foot between rows on a bed.
Question: How are plants irrigated? Answer: There are two lines of T-tape in each raised bed. Irrigation is run daily for an hour.

Southwest Ohio: A storm went through Friday with high winds and took out power. Some tunnels in the area have been damaged, and some plastic and shade cloth have been ripped off. Prior to that it has been very hot, in the mid to high 90's and low 100's, and very dry. Growers have covered tunnels with shade cloth and whitewash to keep things cool. Tomato yields and production are great so far; tomatoes are doing very well. At this time people are beginning to see blossom drop, probably due to the heat. It has gotten too hot for the cool season crops. People are getting busy in the field and so management in tunnels is not as intensive, and they are beginning to see leaf mold and irrigation management issues. Some yellow shoulder is also showing up. Most growers who don't plan to continue harvesting tomatoes in tunnels throughout the summer have topped the plants, and they will finish the crop by the end of July. They intend to switch to their field tomatoes. Some will plant a fall or winter crop in the tunnel after cleaning it out; others will not use the tunnel until next season. Tomatoes planted in the tunnel in Feb. were ready at the end of May. One grower with a 30 ft. X 120 ft. house, has been harvesting 1 ton of tomatoes per week, and selling them retail at $3.00/lb. Demand for tomatoes has been great, with prices $2.00 to $2.50/lb. even for Number 2's at wholesale. The flavor of the tomatoes from tunnels has been really good. Interest in new tunnels is still strong, with half a dozen NRCS EQIP-funded tunnels going up, and another 6 or 8 approved for funding. (Brad Bergefurd)

Daviess County: It has been hot and dry. Storms moved through yesterday, with rainfall varying from about 0.9 to 0.1 inch. People are busy harvesting tomatoes in tunnels. The Daviess County Produce Auction is distributing about 2 tons of tomatoes 3 times a week. Last Friday Number 1's in 10-lb. boxes averaged $11.16/box, with a high of $31.00. Number 2's averaged  $7.20 with a high of $15.00 The auction will fax price and volume reports after each auction on request; call 812-486-2445 to be added to the fax list. (Scott Monroe)

Southwest Indiana: Fusarium crown and root rot was observed in one high tunnel tomato planting last week. This disease is caused by a different organism than Fusarium wilt. Symptoms of the disease include wilting. A lesion may appear on the outside of the stem, and internally there will be discoloration at the base of the stem. In contrast, with Fusarium wilt, no external lesion would be present and internal discoloration would go all the way up the stem. Fusarium crown and root rot could have been introduced in soil, seed, or transplants. There are no curative measures. Practices that may reduce the problem in future years include solarizing the soil after this year's tomato crop, and planting a brassica cover crop and incorporating it into the soil. (Dan Egel and Shubin Saha) 
Question: Would grafting help? Answer: It may help if it makes the plant more vigorous. 'Maxifort', a common rootstock, is reported to be resistant to Fusarium crown and root rot as well as Fusarium wilt, so grafting onto that rootstock should help.

Southwest Purdue Ag Center: The 10 tomato varieties planted in tunnels on March 28 have been harvested since the last week of May. A field day / twilight meeting on July 12 will include a tour of the trial. (See the registration flyer here.) They will probably wrap up the crop in the middle to end of July. Varietal differences in tolerance to changes in environmental conditions are apparent. Temperatures have been high over the past few weeks. Highs of 112°F to 113°F have been recorded in the tunnels in the last few days. This is about 5 degrees warmer than outside. As a result of the high temperatures, flowering may stop soon, and some leaf roll is occurring. There may also be persistent growth regulator injury from the exposure earlier in the season–there are some odd flower clusters, with an unusually large distance between flowers. 
At the start of the season, the crop was irrigated every other day, and based on tensiometers at 6-inch depth, the soil moisture tension was in the desired range of 10 to 20 centibars. Fruit developed blossom end rot (BER) at a high rate. Blossom end rot is associated with low calcium levels in the blossom end of the fruit. Leaf tissue analysis showed calcium levels almost excessive, so a lack of calcium in the soil did not seem to be the likely cause. Uneven or inadequate soil moisture is known to promote BER. They switched to watering 4 times a day, supplying about 1/2 gallon per day per plant. Watering begins just after sun-up and ends just before sundown. A battery-operated solenoid valve is used to turn the irrigation on and off. This particular system has the capability to run 6 different irrigation programs, with varying length of time for the irrigations. The incidence of BER is much lower since this new irrigation timing has been implemented. (Shubin Saha)

Some growers use sprinkler or mist nozzles inside the high tunnel to reduce air temperature. Comments? 
Shubin Saha reported on a trial he and others did in Florida comparing misting and Aluminet shade cloth for a pepper crop in a high-roofed, passively-ventilated greenhouse. They found higher photosynthetically active radiation (PAR) with mist vs. shade cloth. Both systems reduced air temperature: average daily temperatures were 81.0°F (mist), 81.9°F (shade) and 84.7°F (no cooling) in 2004, and 82.9°F (mist), 87.3°F (shade) and 87.4°F (no cooling) in 2005. The shade cloth was more expensive than misting. With cheaper shade cloth (more like what growers in this area use), shade would probably be less expensive than installing a misting system. 
In this area, in low humidity conditions like this year, misting would probably work. In higher humidity conditions, like Florida, or our typical year, misting is not an efficient method of cooling. Another concern with misting is the likelihood of increasing foliar diseases. No increased disease was noted in the pepper crop in the trial above, but in a tomato crop there are several diseases that would be a concern. 

Notes by L. Maynard. Please get in touch with corrections or additions, or just post a comment. 

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