Arrowroot (Maranta arundinacea) is a tropical plant valued for its starchy rhizomes, which are underground stems. These rhizomes are processed into a fine, white flour, a versatile thickener used in sauces, soups, and desserts. Arrowroot flour creates clear, glossy results without imparting a starchy flavor, and is also a popular gluten-free alternative in baking. Beyond its kitchen uses, arrowroot has a history in traditional medicine. This plant can be a rewarding addition for home gardeners interested in cultivating a unique and useful crop.
Preparing for Planting Arrowroot
Selecting the right location is the first step for successful arrowroot cultivation. Arrowroot thrives in warm, humid climates in USDA hardiness zones 8-11, where frost is rare. While it prefers partial shade, especially from intense afternoon sun, it can tolerate full sun in cooler tropical environments. An ideal spot receives morning sun and dappled afternoon light.
The soil plays a key role in the health of arrowroot plants. They require well-draining soil rich in organic matter to support rhizome development. A slightly acidic to neutral pH, between 5.5 and 7.0, is ideal for growth. Before planting, amend heavy clay soils with compost or well-rotted manure to improve drainage and aeration. Sandy soils also benefit from organic amendments to enhance water retention and nutrient availability.
Planting Arrowroot
Sourcing healthy rhizomes is the first step for planting arrowroot. These are available from specialty nurseries or online suppliers. The best time to plant arrowroot is in spring, after frost danger has passed and soil temperatures warm consistently. This allows the plant to establish before the peak growing season.
When planting, prepare individual holes deep enough for the rhizome. Place each rhizome 2 to 4 inches deep in the prepared soil. Ensure the “eyes” or buds on the rhizome face upwards, as new shoots emerge from them. Space the rhizomes 12 to 18 inches apart to allow room for growth and root system expansion. This spacing also promotes good air circulation.
Ongoing Care and Maintenance
Consistent moisture is key for arrowroot, especially in dry periods. The soil should remain evenly moist but never waterlogged, as excessive wetness leads to rhizome rot. Regular watering, especially without rainfall, maintains soil moisture. Monitor the soil’s surface and water when it feels dry to the touch.
Arrowroot plants benefit from regular fertilization to support their growth. Apply a balanced fertilizer, like a 5-10-10, every 4 to 6 weeks during the active growing season. Alternatively, incorporating compost or a slow-release organic fertilizer when planting provides nutrients. Weeding around the plants also reduces competition for water and nutrients.
While arrowroot is resilient, it may encounter pests like spider mites or mealybugs in dry conditions. Inspecting the undersides of leaves periodically identifies infestations early. Organic solutions, such as neem oil sprays or insecticidal soap, manage these pests without harming beneficial insects. Ensuring good air circulation and avoiding overhead watering reduces fungal issues like leaf spot or root rot.
Harvesting and Post-Harvest
Arrowroot rhizomes are ready for harvest 8 to 10 months after planting. A key indicator of maturity is when the plant’s leaves yellow and die back. This signals the plant has directed energy into developing its underground storage organs. Harvesting too early results in smaller, less starchy rhizomes.
To harvest, dig carefully around the plant’s base with a garden fork or spade, avoiding rhizome damage. Gently lift the plant from the soil, then separate rhizomes from the main root system. Brush off excess soil from the rhizomes.
Once harvested, arrowroot rhizomes can be used fresh or processed for storage.
Fresh Storage
For fresh use, store rhizomes in a cool, dark place or in the refrigerator for up to 2 weeks. Wash, pat dry, and wrap loosely in a paper towel before placing in a plastic bag or airtight container.
Preparing Arrowroot Flour
To prepare arrowroot flour, wash, peel, and grate or blend the rhizomes into a pulp. Mix the pulp with water, strain, and allow the starch to settle. The collected starch is then dried, often in the sun, until it forms a brittle powder.
Freezing Rhizomes
Alternatively, fresh rhizomes can be boiled, peeled, cubed, and frozen in zip-lock bags for extended preservation.