How to Grow Clearfield Rice
Wikimedia Commons
Clearfield Rice
Oryza sativa
grassClearfield rice is a herbicide-tolerant variety of cultivated rice developed through conventional breeding to resist imidazolinone herbicides. It allows farmers to use specific herbicides for weed control while protecting the rice crop. This technology has become widely adopted in rice-growing regions for improved weed management.
When should you plant Clearfield Rice in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Clearfield Rice timeline · Pittsburgh, PA (Zone 6b)
-
Plant Clearfield Rice
Around Apr 17Near Pittsburgh's average last spring frost.
-
Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
-
Harvest Clearfield Rice
Around Aug 5≈ 110 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Clearfield Rice dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in warm zones 8-10, particularly suited to southern U.S. rice-growing regions
Sign up free to see if Clearfield Rice grows in your zone — and get a personalized planting timeline.
Get my Clearfield Rice timeline →Growth Stages
Pre-germination & Seedling
7-14 days (germination), 20-30 days (nursery growth for transplants)Seeds are either soaked and broadcast, or planted in nursery beds. Seedlings develop first leaves and root systems.
Keep seedbed flooded or moist; maintain 75-85°F soil temperature for optimal germination. Direct seed at 150-200 lbs/acre or prepare transplant nurseries.
Vegetative/Tillering
40-50 daysPlant develops multiple shoots (tillers) from the base; stem and leaf growth accelerates. Plants establish 4-8 productive tillers.
Maintain 2-4 inches of standing water. Apply nitrogen fertilizer in split applications. Apply imidazolinone herbicides at 2-4 leaf stage to control weeds. Monitor for early pests and diseases.
Reproductive/Booting
15-20 daysPanicle (flower head) emerges from leaf sheath; plant stops producing new tillers and focuses energy on grain development.
Maintain consistent 2-6 inches standing water. Reduce nitrogen to prevent lodging. Monitor for blast disease and insects. Ensure adequate potassium for grain fill.
Flowering & Grain Fill
20-30 daysPanicle fully emerges with florets opening; pollination occurs (typically self-pollinating). Grains begin to fill and mature.
Maintain water levels but begin gradual draining 2-3 weeks before maturity. Avoid extreme temperature fluctuations. Monitor for grain-feeding insects and birds.
Maturation & Harvest
15-20 daysGrains harden and lose moisture; hulls turn golden-brown. Plant is ready for harvest when moisture drops to 20-25%.
Drain field 1-2 weeks before harvest. Harvest when grains are hard but before they become brittle. Dry grain to 12-14% moisture for storage.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
-
Insecticide applications at boot stage; crop rotation; removal of crop residue
-
Resistant varieties; insecticides; proper nitrogen management to reduce plant susceptibility
-
Seed treatments; delayed flooding; insecticides; crop rotation
-
Insecticide sprays; light traps; biological control agents
Uses
Staple grain for human consumption
CulinaryClearfield rice grains are milled into white or brown rice and serve as a primary staple carbohydrate for billions of people worldwide. It can be cooked as steamed rice, risotto, rice flour, or in numerous traditional dishes. [source]
Industrial food processing
CulinaryRice grain is processed into rice flour, rice bran, rice oil, and rice-based beverages. Clearfield varieties are used in commercial food manufacturing due to consistent quality and herbicide-free product assurance. [source]
Animal feed and livestock grain
HouseholdBran, broken rice, and whole grain are valuable feed ingredients for poultry, swine, and cattle. The herbicide-resistant trait ensures clean, contaminant-free feed. [source]
Weed management efficiency
AgriculturalThe Clearfield trait enables farmers to use imidazolinone herbicides for selective weed control, improving yields and reducing hand-weeding labor. This agricultural innovation increases productivity in rice cultivation. [source]
Reduced herbicide application burden
EnvironmentalClearfield technology allows targeted herbicide use instead of broad-spectrum applications, potentially reducing overall chemical inputs when properly managed. Cleaner fields result in better quality grain. [source]
Harvest Tips
Harvest when grain moisture reaches 20-25% using combine harvesters. Allow field to dry for 1-2 weeks after draining. Harvest promptly when ready to prevent grain loss from shattering. Grain should be dried to 12-14% moisture content before storage. Separate chaff and debris using grain cleaners.
Fun Facts
- 🌱 Clearfield rice was developed by the United States Department of Agriculture (USDA) and Louisiana State University Agricultural Center using conventional breeding, not genetic modification, making it acceptable in organic-certified systems in some regions.
- 🌱 The imidazolinone herbicide family used with Clearfield rice works by inhibiting acetolactate synthase (ALS), an enzyme essential for branched-chain amino acid synthesis in plants, effectively stopping weed growth while the rice tolerates it.
- 🌱 Clearfield technology has been widely adopted in Louisiana, Arkansas, and Mississippi, representing over 30% of rice acreage in some U.S. regions due to its effectiveness against problematic weeds like red rice and barnyardgrass.
Gardening Terms
New to gardening? Learn about terms used in this guide:
Join 30,000 gardeners planning their gardens with LizPlants.
Get your personalized Clearfield Rice planting timeline
Tell us your zip code and we'll calculate exactly when to start Clearfield Rice seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.
Get my Clearfield Rice timeline →