Oats (Avena sativa) are a culturally and economically important member of the grass family. More than 20 million tons of oats are eaten each year around the world. We really like our oatmeal!
Like other types of cereal grains, oats are surprisingly easy to grow. It doesn’t take much to grow your own oats in the backyard garden.
In this article, you’ll learn about the different growth stages of oats that make up the plant’s life cycle.
Conditions for Growing Oats
Oats are commonly grown for human consumption and as animal feed. This grass is also excellent as a cover crop to preserve soil quality during the agricultural off-season. Many eco-conscious farmers utilize oats as a green mulch, tilling young plants into the soil before replanting with another crop.
You can grow oats almost anywhere there is full to partial sun exposure and well-draining soil. These plants are challenging and require little oversight to thrive.
Oat plants are annuals. In warm climates (e.g., Zone 7 and higher), it’s common for oat seeds to survive winter and self-seed the following year. The oat plants themselves can typically tolerate temperatures down to 5°F.
Oats need an average of 1 inch of water per week during the growing season. Hotter weather will necessitate more water to prevent heat stress. Fertilizer is rarely required, even when growing oats in poor soil.
Smaller gardens can accommodate up to 25 oat plants per square foot. Oats can be grown in raised beds and other containers as well.
Oats Growth Rate
It takes 100 to 120 days for oats to mature after planting. Most oat plants reach heights of 3 to 4 feet by the end of the season, growing an average of 2 to 4 inches per week.
Growth Stages of Oats
In the agricultural world, cereal grain development is commonly divided into three distinct phases:
- Oats germinate, sprout, and establish a strong base of shoots and roots during the foundation phase.
- The construction phase lasts from the beginning of stem elongation until the oat plant starts to flower.
- Flowering, pollination, and grain ripening are all part of the production phase.
These phases provide a quick overview of the processes that go into growing oats but can be divided up even further for a better understanding.
1. Seed Germination
Oats are traditionally started by broadcasting seeds over the area to be planted and worked in slightly. This process is very reminiscent of producing other types of grass, including those typically used for turf lawns. This is usually done in the spring as soon as the soil is workable.
As I touched on above, oats thrive in cool weather. Their seeds do as well. Oats will germinate in temperatures above 35°F, but according to South Dakota State University, soil conditions above 40°F will promote faster growth.
At the right temperature and with adequate moisture, oat seeds should germinate in 5 to 10 days.
During germination, the seeds take in moisture from the soil. This triggers cell division in the seed embryo, which contains vital structures that will develop into the plant’s first roots, shoots, and leaves.
2. Seedling Development
The first structure that emerges from the soil is the oat’s coleoptile. This is a protective sheath that covers the young shoot and leaf tissue.
Within just a few days of being exposed to sunlight, the oat plant’s first genuine leaf will unfold from the coleoptile. At this point, the primary node (where new growth is occurring) is still below ground.
You may recognize this stage if you’ve worked with other cereal grains. Tillering is the process of new offshoots forming along the oat plant’s main stem. Good tiller production will result in a larger harvest at the end of the season, as the oat plant is able to put out far more flowers and seed heads.
Full tillering occurs around 20 days from planting.
4. Stem Elongation
Stem elongation is precisely what it sounds like. During this phase of growth, the oat stem elongates so that the primary node moves above ground.
5. Ear Emergence
As the oat plant is hard at work producing tiller leaves and getting taller, the young ear is slowly moving up the inside of the stem.
About 60 days after sowing, your oat plant should reveal its flag leaf. This is the final leaf to appear and indicates that the oat plant has reached reproductive maturity.
The young oat ear keeps moving up the stem until stopping just below the flag leaf. Here it will swell up before the flowers emerge.
Oat flowers appear as panicles of loose spikelets that dangle from the top of the stem. The flowers themselves are tucked between modified leaves that protect the blooms and ensuing grain seeds.
An oat plant typically needs at least 60 days to reach the flowering stage. After the plant reaches reproductive age, however, flowering can last for 30 to 50 days.
According to the University of Wisconsin, over 99% of oats are self-pollinating. In other words, you don’t need to rely on bees and other insects to spread pollen from flower to flower.
It takes approximately 5 to 7 days for all of the flowers in a panicle to become pollinated. Once pollen enters a flower ovary, it takes just a few hours for fertilization to occur!
7. Grain Ripening
The oat grains take the place of the flowers. It takes at least 30 to 40 days from flowering for most varieties of oats to ripen.
The oat kernels will begin to thicken as they develop. During the first ten days, known as the milk stage, you can produce a milky liquid by squeezing the young kernels.
The ten or so days following the milk stage is commonly called the dough stage. At this point, the growing kernels contain a soft, doughy substance.
As the growing season comes to a close, the kernels will continue to grow and ‘set’.
When to Harvest Oats
Oat farmers generally wait for the grains to have a moisture level of 35% before harvesting. Home gardeners don’t need to follow such an exact science.
An excellent trick to determine oat readiness is to press a fingernail into the grain. Oats that are ready to harvest will easily dent from this test. By this point, the youngest kernels on the ear should be turning pale yellow.
FAQs Oats Growth Stages
Will oats reseed themselves?
Oats are annual grasses with a life cycle that begins and ends within a single year. With the right weather conditions, however, oat seeds will sprout and produce a second crop the following year.
Can you grow oats on your lawn?
While you can use common oats (Avena sativa) as a short-lived cover crop, the oat grasses you’ve heard of people growing as lawns were probably not oats at all. For example, Danthonia spicata is known as poverty oat grass but is not related to the cereal grain.
- South Dakota State University Soil conditions for oat germination
- University of Wisconsin Oat flower germination
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.