Growing sweet corn is an enjoyable and rewarding endeavor for any gardener.
From the moment of germination to its mature harvest, six distinct stages must be navigated to achieve a successful crop.
It’s like watching a living timeline unfold before your eyes! If you’ve ever wanted to understand the mysterious process behind growing sweet corn, read on to learn about all six stages of growth.
Stage 1: Germination of Sweet Corn
Germination is the first stage of sweet corn growth and begins when the seed absorbs sufficient moisture to start breaking down its endosperm.
As it does, the embryo inside will start to develop and send out a root, called the radicle, that will eventually become part of the plant’s root system.
The seed also produces a shoot that will grow into the corn stalk.
Optimal germination occurs when soil temperatures are between 50-95°F (10-35°C).
If soil temperatures drop below 50°F (10°C), germination may be delayed or inhibited altogether.
Once germinated, sweet corn should emerge from the soil within 10 days.
Stage 2: Vegetative Growth
The second stage of sweet corn growth is the vegetative stage, which begins after the plant has fully emerged from the soil.
During this time, the plant will produce more leaves to increase its photosynthetic activity.
The number of leaves increases as the plant grows taller, and a visible leaf collar should be detectable at around 4-5 inches tall.
At this point, it’s important to ensure that soils are kept moist and free of weeds so that the corn can continue growing without competition.
Soil temperatures should remain between 50-95°F (10-35°C), and 1 inch of water per week should be applied to maintain adequate soil moisture levels.
Stage 3: The VT Tassel Emergence
The third stage of sweet corn growth is the VT tassel emergence.
During this stage, the corn plant continues to grow taller and will produce a tassel at the top of the plant.
The tassel is comprised of tiny flowers that produce pollen, enabling cross-pollination with other corn plants for fertilization to occur.
When the tassel emerges, it’s important to ensure that soil temperatures remain between 50-95°F (10-35°C) and that soils are kept moist – especially if you’re growing your sweet corn varieties as this is a critical period for pollination.
Also, be sure to water your plants at least 1 inch per week during this stage to maintain adequate soil moisture levels.
Poor pollination can result in smaller ears or even no ears at all so it’s important to take care of your corn crop during this time!
Stage 4: R1 Silking of Sweet Corn
Stage 4 of sweet corn growth is the R1 Silking stage. During this stage, the female flowers on the corn tassel will begin to develop silks which are long, thin filaments that emerge from the ear of each corn plant.
This stage typically occurs when the plants have reached full vegetative growth and around 60-90 days after sowing.
The silks are necessary for pollination to occur as they serve as a bridge between the pollen grain and kernel.
It is during this stage that water per week should be increased to at least 1 inch (2.5 cm) to ensure adequate moisture levels in sandy soils or wet soils – as too little moisture can result in poor pollination which can lead to smaller ears or no ears at all.
Also, if you’re growing sweet corn varieties with different maturity dates, it’s important to note that cross-pollination needs to occur within three weeks for fertilization and ear development to occur successfully.
Stage 5: Sweet Corn R2 Blister
Stage 5 of sweet corn growth is the R2 Blister stage. During this stage, the kernels will begin to swell as they fill with sugar contents and starch to be ready for harvest.
This is also when the cob’s outer layer turns a yellowish hue, while the kernel color may vary depending on the variety of sweet corn grown.
It typically occurs around 70-95 days after sowing and requires soil temperatures between 50-80°F (10-26°C) as well as moist soil conditions for successful ear development.
It is important to ensure adequate water levels during this critical period, at least 1 inch (2.5 cm) per week, as too much or too little moisture can lead to off-flavor ears or low yields due to lack of pollination from European Corn Borers or other insects.
As the plants reach maturity, you should be able to see small bumps emerging from the lowest leaves near the visible leaf collar of each plant – these bumps are an indication that it is time to harvest fresh corn!
Stage 6: R3 Milk Phase of Sweet Corn
Stage 6 of sweet corn growth is the R3 Milk phase. During this stage, the kernels will enter the final stage of development and reach a maximum size.
The cob’s outer layer will be deep golden-yellow color, while the kernel color may vary depending on the variety of sweet corn grown.
Typically occurring around 85-110 days after sowing, soil temperature should remain at 50-80°F (10-26°C) and soil moisture levels must remain consistent throughout to ensure successful ear development.
This is also when cross-pollination occurs, as pollen grains are spread from one plant to another by wind or insects which leads to an increase in kernel weight and sugar content in each ear.
Finally, once the kernels are full size and their sugar content has reached its peak, they form a black layer at the bottom of each kernel known as the “black layer” which indicates physiological maturity and it is time to harvest your sweet corn crop!
