Kale is a popular cool-weather crop. Providing the correct distance between plants is the most important factor for maximizing yield and preventing disease. Adequate spacing ensures proper air circulation, which helps dry the leaves quickly and reduces the chance of fungal diseases like powdery mildew. It also prevents competition for sunlight, water, and soil nutrients, allowing the kale to develop large, tender leaves.
Standard In-Ground Spacing Requirements
For growing full-sized, mature kale plants in a traditional garden row setting, space each plant 12 to 18 inches apart within the row. This range accommodates the mature spread of most common varieties, which can grow 18 to 24 inches in diameter. Mature kale plants can reach heights of up to three feet, requiring this wide base for stability and leaf production.
The distance between rows should be 18 to 30 inches to provide space for maintenance tasks like weeding and harvesting. This spacing ensures that the mature leaves of plants in adjacent rows do not touch, maintaining necessary airflow around the plant canopy. Without sufficient room, plants will compete, resulting in smaller, less vigorous growth and a reduced harvest.
Adjusting Spacing Based on Kale Variety
Standard spacing needs adjustment because not all kale varieties share the same mature size. Larger, more vigorous varieties, such as ‘Red Russian’ or ‘Lacinato’ (Dinosaur Kale), require the full 18 to 24 inches of space. This maximum distance accommodates their broader leaf structure and taller stature, ensuring their large leaves fully develop.
Conversely, compact types like ‘Dwarf Blue Curled’ are bred for a smaller footprint, making them suitable for tighter planting. These dwarf varieties tolerate closer spacing, thriving when set 12 to 15 inches apart. This allows the gardener to increase the number of plants in a given area without compromising individual growth.
Intensive Planting and Container Spacing
When maximizing yield in a small area, such as a raised bed, intensive planting methods like square foot gardening can be used. In this technique, a single square foot grid accommodates one full-sized kale plant, allowing for 12-inch spacing. For smaller or dwarf varieties, it is possible to plant up to four kale plants within a single square foot, though this requires consistent monitoring of nutrient and water levels.
For container gardening, the pot size is the primary constraint, as each plant requires a dedicated volume of soil for root development. A single, mature kale plant requires a minimum container size of 5 gallons to thrive throughout the season. If planting multiple kale plants in a large container, each plant should still be given at least 12 inches of space from its neighbor. The container must also be at least 12 inches deep and wide.
Managing Seedlings and Thinning
Achieving the final spacing involves planting seeds densely and then reducing the number of seedlings through thinning. Initially, seeds are sown about a half-inch deep and one inch apart to ensure good germination rates. This density is necessary because not every seed will sprout, allowing the gardener to select the strongest individuals for the final planting.
Thinning should occur once seedlings develop their first set of true leaves, which look like miniature versions of the mature kale leaf. The weaker seedlings are removed by snipping them at the soil line to avoid disturbing the roots of the remaining plants. This selective removal prevents overcrowding, which leads to stunted growth and increased susceptibility to common brassica diseases.