Leafy Greens
Leafy greens represent a diverse group of nutrient‑dense crops grown across several botanical families. These crops are defined by their edible foliage and include staples such as lettuce, spinach, spring‑mix components, arugula, chard, and a range of brassica greens. Because leafy greens are harvested for fresh, high‑quality leaves, they require a fertility program that promotes rapid early growth, uniform canopy development, and consistent nutrient availability through harvest. Their short production cycles and high nutrient‑uptake rates place specific physiological demands on the crop at each stage, making precise, crop‑safe nutrition essential. Tessenderlo Kerley fertilizers deliver readily available nutrients that support vigorous growth and help growers produce uniform, market‑ready leafy greens. The guidelines below outline how to best utilize our products throughout the growing season.
Nitrogen
Nitrogen is essential for rapid leaf expansion, canopy development, and the vibrant green color that defines high‑quality leafy greens. Adequate N supports sustained photosynthesis and drives the protein synthesis required for tender, uniform leaves. However, excessive nitrogen late in the crop cycle can produce overly succulent tissue, reduce shelf life, and increase susceptibility to tip burn and postharvest breakdown.
Controlled‑release nitrogen sources such as N‑Sure®, which contains triazone nitrogen, provide a steady, predictable supply of N when applied through irrigation. The triazone molecule breaks down gradually, improving uptake efficiency and reducing leaching losses, an important advantage in sandy soils or high‑turnover production systems common in leafy‑green production. When blended with conventional N sources like UAN‑32, triazone helps moderate the release pattern and enhances overall nitrogen‑use efficiency. N‑Sure® is also an effective foliar option and can be applied with compatible fertilizers and crop‑protection products to support in‑season nutritional needs.
Potassium
Potassium plays a central role in leafy‑green quality, influencing leaf thickness, turgor pressure, color, and overall marketability. Adequate K improves stomatal regulation and internal water balance, helping crops maintain uniform growth under fluctuating environmental conditions. In fast‑growing leafy crops, liquid potassium fertilizers are well suited for fertigation, enabling precise applications throughout the crop cycle — especially during rapid canopy expansion when potassium demand peaks.
KTS® supplies readily available potassium along with thiosulfate sulfur, which enhances nutrient uptake efficiency. The thiosulfate component is particularly valuable in calcareous soils, where its acidifying effect can increase the availability of phosphorus, iron, and manganese — nutrients essential for leaf color and chlorophyll formation.
K‑Row 23® is ideal for early‑season potassium applications because it is seed‑safe and can be placed close to the seed or transplant. It also supports higher in‑season application rates, providing flexibility during periods of accelerated leaf growth. Together, these products help growers match potassium supply with crop demand throughout the season, supporting consistent, high‑quality leafy‑green production.
Calcium
Ensuring adequate calcium uptake is one of the most consistent nutritional challenges in leafy‑green production. Calcium is essential for strong cell walls and helps prevent physiological disorders such as tip burn, marginal necrosis, and internal breakdown. Because Ca is relatively immobile within the plant, a continuous supply is required during rapid leaf expansion to support proper tissue formation. In sandy soils, common in many leafy‑green regions, calcium availability is often limited due to low cation‑exchange capacity and leaching losses.
CaTs® improves calcium uptake by supplying a highly soluble, readily available form of Ca that moves efficiently through the soil profile. Its thiosulfate component also helps moderate high soil pH and can increase the availability of nutrients such as phosphorus and iron. Since CaTs contains no nitrogen, it can be applied during growth stages when additional N should be minimized to avoid overly succulent tissue. CaTs is also an effective tool for in‑season salinity management; soluble calcium improves soil physical properties, enhances water infiltration, and supports the leaching fraction needed to move salts below the root zone. Maintaining adequate calcium throughout leaf development helps growers produce leafy greens with stronger structure, reduced defect risk, and improved postharvest performance.
Sulfur
Sulfur supports protein synthesis, enzyme activation, and chlorophyll formation, all processes essential for vigorous leaf growth and rich green coloration. Adequate S also enhances nitrogen‑use efficiency by improving the balance between amino‑acid and protein formation. Thio‑Sul® provides a highly soluble, plant‑available source of sulfur that moves efficiently through the soil profile and supports consistent uptake throughout the season. The thiosulfate form of sulfur, found in Thio‑Sul, KTS, and CaTs, also improves nutrient mobility and can help mitigate bicarbonate issues in alkaline irrigation water. In high‑pH or calcareous soils, thiosulfate sulfur acidifies the rhizosphere, increasing the availability of nutrients such as phosphorus, iron, and manganese, which are critical for leaf color and overall plant vigor. Maintaining adequate sulfur throughout the crop cycle supports balanced nutrition and improved nitrogen efficiency.
Florida Farmer Shares How Thio‑Sul Improves Soil pH & Crop Uniformity
In-Season Pest Management for Lettuce
Aphids and thrips can be persistent pests in lettuce, reducing crop quality and marketability through direct feeding damage. These insects may also contribute to the spread of destructive plant diseases, including Impatiens necrotic spot virus (INSV), increasing production risks for growers. Because both pests can reproduce quickly and are often found on protected leaf undersides, timely management is critical to reducing population buildup and limiting crop injury. An integrated pest management approach that combines insect monitoring, sanitation practices, and effective insecticide programs can help growers protect stand health, maintain crop quality, and reduce the potential for pest-related losses.
Lannate® insecticide provides control of aphids and thrips in lettuce as part of a comprehensive pest management program. Powered by methomyl, Lannate delivers rapid contact activity against multiple life stages of target insects and can be incorporated into resistance management programs by rotating with products that have different modes of action. Its translaminar movement helps reach pests feeding on leaf surfaces that may be difficult to contact directly, supporting effective control when used according to label directions.
Well suited for:
- Managing aphid infestations in lettuce.
- Managing thrips populations that can impact crop quality.
- Integrated pest management (IPM) programs.
- Resistance management programs that rotate insecticide modes of action.
- Situations where pests are feeding on lower or protected leaf surfaces.
- Growers seeking flexible foliar application options, including compatible tank-mix programs where allowed by label.
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