How to Water and Fertilize Sweet Corn for Maximum Yield

How to keep your corn patch thriving from seedling to harvest.

Over many seasons of growing sweet corn in both raised beds and traditional garden rows, I’ve learned that consistent watering and a well-timed fertilizer schedule are key to getting big, juicy, fully developed ears. Corn is a fast grower and a heavy feeder—if you meet its needs from the start, you’ll be rewarded at harvest time.

Table of Contents

Watering Sweet Corn: Keeping Moisture Consistent

Corn is a member of the grass family, and like most grasses, it needs consistent, even moisture—especially during rapid growth and pollination. In my experience, even one dry spell during the flowering stage can lead to spotty ears with missing kernels.

How much water?
Aim to give your corn 1 to 2 inches of water per week (roughly 6 to 12 gallons per square yard), depending on the weather. In especially hot or windy conditions, increase watering frequency to prevent stress and wilting.
How to water?
I recommend drip irrigation or a soaker hose placed at the base of the plants. This keeps water off the foliage and tassels and prevents interference with pollination, which happens when the tassels release pollen onto the silks. Overhead watering can wash away pollen and reduce kernel formation.
Mulch matters.
After watering, apply a layer of straw mulch around the base of your corn plants. This helps regulate soil moisture, suppress weeds, and protect the shallow roots from drying out.
When to water?
Use the finger test: Stick your index finger into the soil about 2 inches deep. If it comes out dry, it’s time to water. I check soil moisture every morning during peak summer heat.
Water stress symptoms.
Wilting leaves, slow growth, and incomplete ears are all signs of water stress. Pollination can fail when silks dry out, so it’s crucial to keep soil evenly moist when tassels and silks emerge.

Sweet corn needs consistent moisture from early growth

Fertilizing Sweet Corn: Fueling Growth with Nitrogen

Sweet corn is a heavy feeder—one of the heaviest in the vegetable garden. To support its rapid growth and ensure large ears with full kernels, corn needs nutrient-rich soil from the start, especially high in nitrogen.

Here’s how I fertilize for best results:

Before planting:
In the fall or winter before planting, I work aged manure and compost into the soil to build fertility. In spring, before sowing seeds, I add a band of aged compost or composted manure into a shallow furrow—about 2 inches to the side and 1 inch deeper than where I’ll plant the seed. This setup gives seedlings a nutrient boost as roots grow down and outward.
Early season feeding:
Once plants reach 8 to 10 inches tall, I side-dress with aged compost, compost tea, or a nitrogen-rich fertilizer.
I repeat the side-dressing when stalks reach 18 to 24 inches tall, and again at tasseling, when the plants are preparing to pollinate.
Best organic nitrogen sources:
- Blood meal
- Feather meal
- Alfalfa meal
- Cottonseed meal
- Aged chicken manure
  These fertilizers deliver a steady nitrogen supply for leafy growth and ear development.
Crop rotation and green manure:
To maintain soil fertility long-term, I include legumes like clover or vetch in crop rotation. These green manures fix nitrogen in the soil and help prep the ground for next season’s corn. Corn also grows especially well after nitrogen-fixing beans or peas.
Ongoing support:
Every 3 to 4 weeks during the growing season, I side-dress again with aged compost. This keeps nutrients available as corn moves through its fast growth stages.

Final Tip: Feed and Water Together

For best results, I water after every fertilizer application to help nutrients reach the root zone. Mulch also helps slow evaporation and keeps nutrients from washing away too quickly.

With a solid plan for even watering and timely feeding, you’ll be on your way to growing plump, sweet ears of corn that are perfect for summer grilling or eating straight from the garden.

Sweet Corn Watering & Fertilizing Calendar

(Based on a 10- to 12-week growing season)
Tip: Adjust start week depending on your local planting date.

Week	Task	Details
Week 0 (Planting Week)	🌱 Pre-Plant Soil Prep	Add aged compost + aged manure to bed. Mix in nitrogen-rich amendments (e.g., cottonseed meal).
	💧 Water After Planting	Lightly water after sowing seeds to settle soil. Keep moist.
Week 1	💧 Establish Moisture	Water 1″ per week. Use mulch to maintain even moisture.
Week 2	💧 Water	Maintain moisture level. Drip or soaker hose is ideal.
Week 3	💧 Water	Monitor with finger test. Avoid letting soil dry out.
Week 4	💧 Water	Same as above.
Week 5	🌿 First Side-Dress Feeding	Apply aged compost or nitrogen-rich organic fertilizer when stalks are ~8–10″ tall. Water afterward.
	💧 Water	Maintain 1–2 inches of water/week.
Week 6	💧 Water	Crucial for steady growth. Mulch can be refreshed.
Week 7	🌿 Second Side-Dress Feeding	When stalks are ~18–24″ tall. Add compost, blood meal, or feather meal. Water after.
	💧 Water	Especially important during warm weather.
Week 8	💧 Water	Tassels may begin forming—avoid overhead watering now.
Week 9	🌽 Tassel Stage	Hand-shake stalks gently each morning to help pollination.
	💧 Water	Keep silks moist—not soggy. Never let soil dry out now.
Week 10	🌿 Final Feeding (Optional)	Light side-dress with compost tea or aged compost as ears form.
	💧 Water	Continue 1–2″ per week; more if hot.
Week 11–12	🌽 Ear Fill Stage	Maintain moisture. Gaps in ears often due to poor watering/pollination.
	💧 Water	Critical final watering period. Don’t let up until harvest.
Week 13+	🌽 Harvest Time	Stop watering 2–3 days before picking to concentrate sugars in ears.