Extension

Best Management Practices for Asparagus Production in Oklahoma

Sathvika Gurelli, Graduate Student, and Tyler Mason, PhD, Vegetable Extension and Research Specialist

Asparagus is a cool season crop that performs well in Oklahoma. Employing the use of timely management practices facilitates high yields this season and potentially for the next 20 years. The season begins with mowing last year’s growth. Post-emergent, nonselective herbicides are often applied at this time because the crop is not exposed. This facilitates new spears emerging in a relatively clean patch. Consistent moisture and weed management are key to this perennial crop especially if one has perennial grass weed species. It is also important to provide adequate fertilizer. Based on soil test results, nitrogen is typically applied annually at about 100 pounds per acre.

Harvests typically occur between April and May. Starting from crown, it is typical to harvest daily for 2, 4, 6 and 8 weeks in production years (after planting) 1, 2, 3 and 4, respectively. It is recommended to stop harvesting spears once they are less than 3/8” in diameter so that the crop can accumulate photosynthates for next year. Make it a habit to scout regularly for cutworms, asparagus beetles and aphids. Pest pressure can be more severe if the crop is under stress, which could be attributed to dry conditions, inadequate fertility and/or an extended harvest season. Top performing Oklahoma grown asparagus cultivars include ‘Jersey Knight’ and ‘UC-157.’ ‘Purple Passion’ is another option for those interested in purple spears, but the yields are lower than its counterparts.

The Balancing Act of Tomato Planting Times

Courtney DeKalb-Myers, Assistant Extension Specialist for Consumer Horticulture

April 15^th marks the average last frost date for most of Oklahoma. It’s important to note, though, that this is an average. Freezes may end as early as March or sneak up on gardeners in early May. Warm season vegetables can be planted once the freeze threat has passed.

This is true for tomatoes, one of the most beloved garden vegetables. Even though tomatoes are a warm season crop, they are not particularly heat tolerant. Tomatoes are native to the high elevations of the Andes Mountains and prefer warm, mild days and cool nights. Specifically, plants perform best with daytime temperatures between 70° and 76°F and nighttime temperatures around 68°F. These conditions only exist in Oklahoma for a short period before transitioning into a much hotter environment.

The cool nighttime temperatures are critical for fruit set. When exposed to higher than optimum temperatures, pollen development accelerates and viability is reduced before fertilization can occur. Flower structure can also be distorted by high temperatures, making it difficult for pollen to be properly transferred within the flower.

This makes determining optimal tomato planting times challenging. Plant too early, and plants may be exposed to a late freeze. Planting too late may result in blooms occurring outside ideal fruit set conditions. In a small garden, it’s easier to protect plants from fluctuating temperatures, but this becomes more challenging in larger gardens and commercial operations. Additionally, larger-scale operations often utilize equipment to assist with transplanting. Heavy spring rains may make it difficult to get into the field, pushing planting times later.

A possible solution is to utilize succession planting. Succession planting is the concept of spacing out plantings so that harvests are more gradual. This is a common practice with single-harvest crops, such as root vegetables. Succession planting for tomatoes can help spread out the risk of exposure to unfavorable temperatures.

Prioritize heat-sensitive varieties for the earlier plantings, so that they ideally have maximum exposure to optimal temperature conditions. For later plantings, utilize heat-tolerant varieties. Some readily available heat-tolerant varieties include Heatwave, Heatmaster, and Celebrity. Small-fruited tomatoes, like cherries, are also easier to grow in high temperatures and can be planted later with minimal risk.

Successfully growing tomatoes in Oklahoma often comes down to timing and flexibility. Monitoring weather conditions and staggering plantings can help ensure at least part the crop develops under favorable conditions. With a little planning, tomatoes can remain a productive and rewarding crop throughout the season.

Don’t Cut Spring Flowering Bulbs Too Early!

David Hillock, Senior Extension Specialist for Consumer Horticulture and Statewide Master Gardener Coordinator

As spring flowering bulbs such as tulips, daffodils, hyacinths, etc. finish blooming, if possible, allow the foliage to turn yellow and die back. The leaves should be easily removed by just tugging on them when they have completely died back. Allowing the leaves to remain on the plant until they turn yellow allows the photosynthesis process in the green