Tomatillos (Physalis philadelphica) are a unique member of the nightshade family, the Solanaceae, and are highly valued for their tart, slightly citrus flavor, which is the foundation of authentic salsa verde. Often called the husk tomato due to the papery lantern that encases the fruit, the tomatillo is a close relative of the common garden tomato (Solanum lycopersicum). Because of this botanical relationship and the similar appearance of their seedlings, gardeners frequently wonder if the deep-planting technique used for tomatoes also applies to tomatillos. Understanding the specific biology of the tomatillo plant provides the answer for transplanting success.
The Deep Planting Distinction
The question of whether to plant tomatillos deeply, like tomatoes, is answered with a definitive “yes.” This practice is highly recommended for building a stronger, more resilient plant. Like their tomato cousins, tomatillos possess the physiological ability to develop adventitious roots directly from their buried stem tissue. When a portion of the stem is placed underground, it actively produces new roots that supplement the existing root ball, resulting in a significantly more extensive root system. This deep planting method creates an anchor for the mature plant, which is beneficial because tomatillos are vigorous, sprawling producers. Burying up to two-thirds of the seedling’s stem ensures maximum root development and increased stability against wind and heavy fruit load. Ensure the soil is well-draining to prevent the buried stem from sitting in overly saturated conditions, which could lead to rot before the roots can fully develop.
Tomatillo Root System Structure
The success of deep planting is rooted in the tomatillo’s capacity for adventitious rooting, a trait shared across the Solanaceae family. Adventitious roots are formed from non-root tissue, specifically the stem submerged below the soil line. These new roots grow from tiny, pre-existing structures on the stem, which look like small bumps or hairs, and they quickly integrate into the soil network. This biological process allows the plant to transform a portion of its stem into a functional root system, dramatically increasing its surface area for nutrient and water absorption. A plant with a greater root mass is better equipped to handle environmental stresses like drought and heat during the long, warm growing season. The resulting deeper root zone also helps the plant anchor its substantial, bushy growth habit.
Step-by-Step Planting Guide
To transplant a tomatillo seedling successfully, prepare a planting hole deep enough to accommodate the entire stem up to the first healthy set of leaves. Remove all the lower leaves from the stem, and gently loosen any roots that may be tightly bound in the nursery pot to encourage outward growth. The goal is to bury approximately two-thirds of the plant’s total height. Set the seedling into the prepared hole and backfill the soil around the buried stem, ensuring the soil is firmed gently but not compacted. This maximizes the stem’s contact with the soil, stimulating the formation of new adventitious roots. Tomatillos are known for their wide, sprawling growth, so adequate spacing is important for air circulation and light penetration. Plants should be spaced at least two to three feet apart in the garden to allow for their mature size, which can reach three to four feet in height and width.
Post-Planting Support and Care
Immediately following the deep transplant, the tomatillo plant will benefit from the addition of a stake or cage. Their indeterminate and bushy growth habit will quickly become too heavy for the newly established roots to support alone. Installing support structures at the time of planting prevents later root disturbance and ensures the heavy, sprawling branches are kept off the ground. Support is also beneficial because it promotes better air circulation, which can help mitigate fungal diseases. Tomatillos are not self-fertile, meaning they require cross-pollination to set fruit, so it is necessary to plant at least two tomatillo plants to ensure a harvest. Pollinators like bees are needed to transfer pollen between the different plants. After transplanting, apply about one to one-and-a-half inches of water per week, watering the soil at the base of the plant to keep the developing root system consistently moist without becoming waterlogged.