Cilantro is a versatile herb cultivated for both its leaves and its dried seeds (coriander). Achieving a steady supply of tender leaves depends significantly on proper spacing in the garden. Planting distance is a determining factor for two primary reasons: it helps prevent the plant from prematurely bolting, or going to seed, and it ensures adequate air circulation around the developing foliage.
Proper Spacing for Optimal Growth
When sowing seeds directly into the garden bed, the planting depth should be shallow, generally between 1/4 to 1/2 inch below the soil surface. This shallow depth allows the seeds to germinate efficiently in the cool, moist conditions they prefer. For the initial sowing, place seeds approximately 1 to 2 inches apart in the row. This close proximity is intentional because not all seeds will germinate, providing a margin for error. The distance between each row should be much wider to ensure accessibility for maintenance and to facilitate air movement, typically ranging from 12 to 18 inches apart.
If you are using nursery-started transplants, the initial spacing is simpler because you are placing the plants at their final, mature distance immediately. These transplants should be set into the soil about 6 to 8 inches apart from one another. Since cilantro does not tolerate root disturbance well, direct sowing is generally preferred. However, transplants must be handled delicately to minimize shock and ensure successful establishment.
Managing Density Through Thinning
Because cilantro is sown densely to ensure a full row, the process of thinning out excess seedlings is mandatory for successful cultivation. Overcrowding is a major cause of stress, which triggers rapid bolting, especially as temperatures begin to rise. Tight spacing also restricts air circulation, creating a humid microclimate that can increase the risk of fungal diseases.
Thinning should occur once the seedlings have developed their first set of true leaves, which are the specialized leaves that appear after the initial, round cotyledons. This usually happens when the young plants are about two inches tall. At this stage, you should remove the weaker seedlings to leave the strongest plants behind. The goal of this process is to achieve a final, permanent spacing of 6 to 8 inches between each remaining plant. It is best to snip the unwanted seedlings at the soil line with small scissors rather than pulling them out, which can disturb the delicate roots of the plants you intend to keep. The removed thinnings are perfectly edible and can be utilized immediately as baby cilantro in the kitchen.
Staggering Plantings for Continuous Harvest
Cilantro is a cool-season annual that bolts quickly once the weather turns hot, which halts the production of fresh leaves. To counteract this natural tendency, gardeners should employ a technique called succession planting. This method involves staggering small, regular plantings over time instead of planting the entire batch of seeds at once.
To ensure a continuous supply of fresh leaves, new seeds should be sown every two to four weeks. This temporal management strategy ensures that as one batch of plants begins to mature and bolt, a younger batch is simultaneously coming into full production. Staggered plantings should continue from early spring until the intense heat of midsummer begins. Once the soil temperature consistently reaches 75°F, cilantro will inevitably bolt, regardless of spacing or thinning. At this point, succession planting should cease, and the focus can shift to planting a final batch in the cooler temperatures of the late summer or early fall for a second harvest season.