The best sweet corn is picked for fresh eating. There is also popcorn, flour corn and ornamental corn. Corn must be planted in blocks to allow for good wind pollination. However, corn works well interplanted with beans and squash (the “3 sisters”). It can also provide shade in the heat of the summer for salad greens.
Corn requires full sun, at least 6 hours of direct sun, and moist, well‐drained soil. Prepare the planting area by mixing 3‐4” of composted manure, lime and cottonseed or fish meal (3#/100 sq ft.) into the top 6‐10” of the soil.
Corn thrives in warm weather and is best planted outdoors May through June when soil temperatures are in the 60s. You can start seeds indoors in late April through May, 1‐2 weeks before desired transplanting date. Corn roots dislike disturbance so try to avoid pot bound plants.
If your transplants have multiple stalks leave the root ball intact and pinch extra stalks so you are left with one or two seedlings.
When soil temperatures are in the 60s, corn can be direct seeded. Plant seeds outdoors 1” deep, 4” apart, in 6‐8” deep rows. Cover seeds with a tin layer of soil or compost. Seedlings or seeds should be planted in blocks of at least 2‐6 rows of 4+ plants spaced or thinned 8‐12”apart. You can also try the hilling method in a 3’x3’ area by creating a mound at each corner and plant 3‐4 stalks or seeds per mound. You can cover new plantings until seedlings are a few inches tall to deter birds from uprooting seedlings. Keep new beds well weeded.
Most varieties will produce two ears per stalk. You can extend your corn season by doing successive plantings through early summer or plant a selection of varieties that mature at different times.
How much water your plants will require depends on the soil and weather. Corn is somewhat drought tolerant, but it yields best with a steady supply of moisture, especially during tasseling. Corn prefers drip or flood irrigation, or deep hand watering. A 1” layer of compost over planting area helps maintain soil moisture.
Corn is a very heavy feeder. Use a high nitrogen foliar spray such as fish and kelp every 7‐14 days until the plants begin to tassel at the top of the plants. Then stop fertilizing.
Most varieties will be ready for harvest 3 weeks from when the first silks appear on baby ears. Ripe ears have dry, brown silks and ears that feel full to the tip. A further test is to peel back the husk a little (do not pull the silks down) and pierce a kernel with your fingernail. If it has a white milky juice it is ready to eat. If the juice is clear, wait a few days.
Sweet corn is best eaten immediately after harvest. It can hold its flavor for 2‐4 days in the refrigerator. Older sweet corn is great for chowders and canning. Sweet corn can also be dried or frozen when removed form the cob.
Popcorn, flour corn, and ornamental corn are all picked when husks are brown and partially dried. Ears are hung and dried in a warm, well‐ventilated area or solar drier. Kernels are ready for storage when they fall off the cob or are easily rubbed off.