Tag Archive for: Organic

, , ,

True Love, Tomatoes, and Trouble: Managing Heat Stress in Tomato Production

By Andy Pressman, NCAT Sustainable Agriculture Program Director

“Homegrown tomatoes, homegrown tomatoes,
What’d life be without homegrown tomatoes?
Only two things that money can’t buy
And that’s true love and homegrown tomatoes.”

– Guy Clark, Homegrown Tomatoes

Listen to a clip of “Homegrown Tomatoes” by Guy Clark

The author’s daughter enjoying a homegrown tomato.

It sure is hard to imagine life without homegrown tomatoes. For some, like American folk singer Guy Clark, it is well worth the wait over the winter months for a sun-ripened tomato fresh off the vine, and for the experience of first biting into one and feeling that rush of flavor as it explodes in your mouth. This moment of joy is not limited to gardeners—anyone can seek out these precious, homegrown flavors from farmers who grow tomatoes skillfully and with great care.

Tomatoes are a staple summer crop for many diversified farms: high-value, in-demand, and, when conditions are right, highly productive. But as summers grow hotter and more unpredictable, even this dependable crop can show signs of stress. Blossom drop, sunscald, delayed or uneven ripening, and declines in yield are symptoms caused by intense heat.

Whether you’re selling at farmers markets, through CSA shares, or to wholesale accounts, heat stress in tomato production can quickly translate into lost income. With the right strategies, you can mitigate heat-related issues and maintain healthy, productive plants, even at the height of summer. Read on for common heat-related issues and how to solve them.

Fruit Set and Blossom Drop

Heat can impede fruit set when daytime highs are consistently over 90°F and nighttime temperatures stay above 70°F. Blossoms can drop and pollen can become less viable as the plant shifts from reproductive to survival mode. Choosing heat-tolerant varieties and staggering plantings to avoid peak summer stress, including planting early in high tunnels, can reduce blossom drop. Using hoops and shade cloth in the field can reduce the sun’s intensity. Managing soil temperature and moisture by utilizing practices such as drip irrigation and mulching can also help retain flowers.

Close-up of a tomato blossom. Photo credit: Nina Prater.

Pollination

Fruit deformities can result from a lack of pollination. Planting pollinator habitats in and around tomato plantings can increase pollination from native pollinators. It’s also a good idea to limit insecticide use (even organic-approved insecticides) during bloom periods. Hand-pollinating plants can improve pollination rates, especially in high tunnels. Applying a kelp or seaweed fertilizer as a foliar spray during early flowering also helps mitigate heat-related stress that impacts pollination and causes misshapen fruits.

Sunscald

Sunscald on tomatoes occurs when the fruit is exposed to intense sun, especially after the plants are pruned and leaf cover is reduced. Sunscald causes the fruit to develop leathery white or gray patches on the skin that make it unmarketable. Maintaining leaf canopy during periods of extreme heat by limiting pruning and sucker removal can reduce sunscald. Trellising can assist in providing more leaf canopy, while also assisting with airflow. And, as with blossom drop, utilizing shade techniques in high tunnels or in the field can reduce the risk of sunscald during periods of intense heat.

Ripening Issues and Yellow Shouldering

Extended periods of high temperatures can cause uneven or delayed ripening, and can also cause the fruit to exhibit green or yellow tops, known as yellow shouldering. Managing potassium availability in the soil can help prevent these issues. Use soil tests to determine potassium levels and apply amendments, such as kelp meal, as needed. Adding too much nitrogen, especially late in the season, can prolong vegetative growth, which slows fruit ripening. If daytime heat is affecting the color or appearance of the fruit, consider harvesting early and ripening indoors.

Blossom-End Rot

Another disorder caused by heat stress is blossom-end rot. While tied to inadequate amounts of calcium, blossom-end rot is more associated with a lack of water. The hotter the temperature, the more water is lost to transpiration from the tomato plants. This increase in water loss causes small lesions on the blossom end of the fruit that gradually spread and turn the area into a brownish or tan color. Timely irrigation and maintaining proper pH and calcium levels in the soil can prevent blossom-end rot.

White Core

Variety of beautiful heirloom tomatoes. Photo credit: USDA Lance Cheung.

Internally, tomatoes can develop a hard white core from excessive heat and inadequate fertility. In moderate cases, white core can occur just beneath the flower-shaped leaf, or calyx, on the top of the fruit. In more extreme cases, you may see white core extend through the entire fruit. Having adequate foliage cover and potassium levels can prevent white core. Additionally, older varieties are more susceptible to white core, while newer varieties are less prone to this issue. Therefore, variety selection can again help mitigate this disorder.

Fruit Cracking

Mid- to late-summer tomato harvests often occur during dry periods. However, an afternoon shower can cause the fruit to swell faster than the skin can stretch, resulting in fruit cracking. Fruit cracking can also occur through sudden irrigation during a dry spell. Cracking can be managed by reducing moisture fluctuations, and through the consistent use of drip irrigation. Mulching conserves soil moisture and reduces the risk of temperature swings. If a sudden rain shower is in the forecast after a dry spell, harvesting tomatoes at first blush or the breaker stage (a slight change in color from green to no more than 10% pink, red, orange, or yellow) and ripening indoors will keep the fruit from cracking. Research shows that ripening in a protected structure at temperatures between 55° F and 65° F is equal to ripening on the vine, while ripening at 68° F increases the sweetness and overall flavor of the tomato.

Tomatoes may love the heat, but even they have their limits. By observing your plants closely, using techniques to mitigate heat stress, choosing the right varieties, and managing soil and water strategically, you can protect your crops and enjoy a fruitful harvest. And, while the summer heat may test your patience and your plants, there’s still something magic about harvesting a perfect slicer in the middle of July—enough to make you hum a little of Guy Clark’s tune on your way back from the field.

Read more on tomato production in our ATTRA publication, Organic Tomato Production.

, ,

Organic Transition Training Coming to Great Falls

Stipends Available for Beginning Farmers and Ranchers to Attend

The National Center for Appropriate Technology, along with nationally recognized organic leaders, will offer an Organic Academy Road Show (OARS) training at the Mansfield Convention Center in Great Falls, Montana, on December 6 and 7, 2023. Beginning farmers and ranchers in the Northern Great Plains will have the opportunity to explore regenerative, certified organic production systems for livestock, grains, oilseeds, and pulses.

Thirty stipends for beginning farmers and ranchers are available for up to $200 each to defray the costs of attending. There is no registration fee, but registration is required. Online registration is available at NCAT.ORG/EVENTS.

This event will host intensive training sessions and one-on-one technical assistance for beginning farmers and ranchers. Topics will include developing an organic system plan, the economics and markets for organic products, considerations when transitioning an operation, working with an organic consultant, and more. There will be time for questions and crowdsourcing ideas with experienced organic farmers and ranchers including Nate Powell-Palm, Doug Crabtree, Margaret Scoles, and others. Thursday’s session will conclude with a tour of an organic processing facility. The event schedule can be found here.

“This series of educational opportunities is not just another farming training,” said Doug Crabtree and Anna Jones-Crabtree of Vilicus Farms in Montana. “It is about leveraging training to further build the network of beginning organic producers who are farming and ranching at a scale that will have a tremendous impact on land stewardship across the Northern Great Plains.”

OARS attendees who are farmers and ranchers transitioning to organic can also apply for a complimentary two-day conference pass to the Montana Organic Association Conference, December 8-9, 2023, also at the Mansfield Convention Center.

The OARS sessions are part of the three-year federal Beginning Farmers and Rancher Development Program, Preparing a Resilient Future, in partnership with the Montana Organic Association, Northern Plains Sustainable Agriculture Society, Center for Rural Affairs, the Intertribal Agriculture Council, Nebraska Sustainable Agriculture Society, International Organic Inspectors Association, North Dakota State, and University of Wyoming.

The project targets medium to large-scale field crop and livestock operations, unlike most programs focused on beginning farmers and ranchers. This project was selected in a national competition under the Beginning Farmers and Ranchers Development Program funded through the USDA National Institute of Food and Agriculture.

Organic Gardening Workshop Begins NCAT’s Summer Sustainable-Growing Series on May 21

The National Center for Appropriate Technology’s popular summer gardening and market-farming workshop series begins May 21 with a practical look at preparing an organic garden.

NCAT operates a high-altitude urban demonstration farm in Butte through its Small-Scale Intensive Farm Training program (SIFT) that is focused on food production for the good of the community. NCAT staff will host the free monthly Saturday workshops from 10 a.m. to noon. RSVP for the SIFT Series events here.

The workshops will be held at NCAT’s SIFT farm, located at 3040 Continental Drive in Butte.

The May 21 workshop will be a hands-on lesson in composting basics, including organic potting mixes, organic soil amendments, cover crops, and mulching methods. It also will cover scheduling planting throughout the growing season and the importance of “hardening off” plants – allowing them to transition from an indoor environment to what can be a challenging growing environment in the Butte area.

The workshop is being held in conjunction with Montana Tech’s Earth Month and the Clark Fork Watershed Education Program.

The other workshops on tap throughout the summer include:

June 25. Analyzing your Soil and Creating a Management Plan: This workshop will include methods to analyze soil types, conduct water infiltration tests, and review soil tests. It will look at management strategies to address the needs of the soil and develop a plan to meet those needs. The workshop will address tillage and the degradation of soils; irrigation and soil water-holding capacities; and custom cover crop mixes to meet soil needs.

July 2. Benefits of Increasing Biodiversity: This workshop will focus on how building more biodiverse ecosystems can be beneficial by increasing pollinator habitat, bolstering integrated pest management, and mitigating risk in cropping strategies. The workshop will include planting drought-tolerant native species and touring SIFT’s native hedgerow.

August 13. Harnessing the Sun’s Energy for Season Extension in Southwest Montana: In conjunction with the 11th Annual Montana Clean Energy Fair, which will be held at NCAT’s headquarters, SIFT will be holding an open house and tour. Topics will include high-tunnel construction and solar passive greenhouses, as well as the costs, construction, and functions of useful season-extension tools for Southwest Montana. Visitors will learn about using the resources readily available to operate a sustainable farm.

September 10. Choosing Varieties to Grow in Butte: This workshop will include NCAT’s annual taste test of successful varieties of fruits and vegetables grown as a trial on the SIFT Farm. The discussion will include timing, growing tips, and seed selection for high yields in Butte. A discussion of seed saving basics for a resilient farm and garden is also planned.