An Introduction to Soilless Strawberries
BACKGROUND
Strawberries have been cultivated for centuries, with modern domestication beginning in the 18th century. While strawberries are predominantly cultivated in outdoor fields, doing so comes with limitations such as seasonality, pests, and diseases, restricting production and reducing crop yields.
Protected soilless strawberry cultivation began gaining traction in Japan in the 1980s and 1990s, as a means to extend the growing season to meet consumer demand. With the effects of climate change and soil-borne diseases limiting the diversity of suitable outdoor cultivars, indoor cultivation differentiates itself through increased flexibility, allowing growers to prioritize varieties with superior flavor, quality, and consistency.
HOW STRAWBERRIES GROW
Strawberries are perennial fruiting plants known for their low-growing habit and sweet fruit. The strawberry plant consists of a crown, from which leaves, flowers, and runners emerge, along with a shallow root system.
“Runners” – are long, thin stems that grow from the base (crown) of the strawberry plant and are capable of producing new plants, called "daughter plants”.
Why Pesticide Free Matters: The Case for Soilless Strawberries
A GROWING DEMAND FOR CLEANER PRODUCE
Strawberries consistently top the Environmental Working Group's (EWG) Dirty Dozen™ list, a ranking of fruits and vegetables with the highest levels of pesticide contamination. Despite rigorous rinsing and washing, over 99% of non-organic strawberry samples tested by the USDA were found to contain pesticide residues, with nearly 30% carrying residues from ten or more pesticides. These contaminants include substances linked to cancer, reproductive harm, and hormone disruption.
THE ADVANTAGE OF SOILLESS STRAWBERRIES
Soilless strawberry production offers a distinct advantage over soil-based methods by significantly reducing the need for chemical pesticides, resulting in cleaner, safer produce. In traditional soil farming, strawberries are often exposed to a wide array of pests, soil-borne diseases, and weed pressures, which necessitate the heavy use of chemical treatments, including toxic fumigants.
By contrast, soilless systems like aeroponics operate in a controlled environment where the absence of soil eliminates many common threats, such as nematodes and pathogens. This minimizes or eliminates the use of pesticides, ensuring that the strawberries are not only free of harmful residues but also grown sustainably. Additionally, the closed-loop systems in soilless cultivation prevent pesticide runoff, protecting surrounding ecosystems while delivering strawberries that meet the growing consumer demand for ultra-clean, high-quality produce.
Soilless Strawberry Basics
A typical soilless strawberry operation will operate in a greenhouse or indoor farm, using outsourced strawberry planting transplanted into pots or troughs containing a soilless substrate mixture.
PLANTING DENSITY
In commercial soilless strawberry cultivation, strawberries are typically grown in rows of 8-10 plants per square meter.
PLANTING SYSTEM/SUBSTRATE
Most greenhouse strawberry production utilizes steel troughs filled a coco-based soilless substrate mixture. These mixtures, often consisting of coco coir blends with high porosity, are suspended above the ground in steel gutters. A synthetic liquid fertilizer blend is applied to the substrate in small quantities using pressure-compensated drip emitters connected to a main irrigation line to ensure the substrate remains appropriately wet over the course of the day.
SOILLESS STRAWBERRY YIELD
During the typical 6-month off-season for open-field cultivation, greenhouse strawberry production can range from 5 to 10 kg per square meter—significantly higher than the 3 kg per square meter yield in the field. It's important to note that yield is heavily influenced by the choice of strawberry cultivar, as some varieties are better suited to greenhouse conditions than others.
While most soilless strawberry production systems will be far more consistent and productive than a traditional outdoor system, the resulting efficiency, reliability, and productivity will largely depend upon the level of technology being used to operate the space.