You must isolate popcorn from other types of corn.
Plant seeds one inch deep in heavier soils, and up to two inches deep in sandy soil. Space the seeds about 8 inches apart. Plant in at least four rows, with 18 to 24 inches between rows. Popcorn germination takes longer than sweet corn, and most varieties require 90 to 120 days to reach full maturity.

What is the proper way to harvest and store popcorn?
This info is provided by Iowa State University

How do you harvest and store popcorn?

Answer:
The moisture content of popcorn determines its popping quality. The ideal moisture content of popcorn is 13 to 14.5 percent.

Popcorn should be left on the stalk until fully mature. Harvest the ears when the husks are brown and the kernels are hard and shiny. After harvest, remove the husks and place the ears in a mesh bag and hang the popcorn in a warm, dry, well-ventilated location for a few weeks. After drying the popcorn for 2 to 3 weeks, remove an ear of popcorn. Shell a portion of the ear and pop the kernels. If the kernels contain too much moisture, the popped corn will be small, rough, and "chewy."
Allow the popcorn to dry for another week. Then shell and test pop a few additional kernels. When the kernels pop well, shell the remainder of the popcorn. The chaff can be removed by pouring the kernels from one container to another outdoors, allowing the wind to remove the debris. After the popcorn has been cleaned, store the kernels in airtight containers.

Ornamental/Edible Popcorn Seeds

TPF245 Carmel Crisp
These seeds are bred for making caramel corn. The shape helps delicious caramel coating to cling to the popped kernel. Great flavor and large size ensure that Caramel Crisp popcorn seeds are a treat for snacking even without a caramel coating! The sturdy corn plants are Goss Wilt tolerant and will yield large single ears. Originally bred for the caramel popcorn industry, Caramel Crisp Popcorn corn seeds produce single, large cobs with kernels that pop into huge, uniquely mushroom-shaped popcorn. As fresh corn goes, it is tasty and sweet. The sturdy plants are Goss Wilt tolerant. 105 days.
Available only in Treated Seed.
 11g pack ( about 45-50 seeds per pack ) $2.95
TPF248 Purdue 410 Hybrid Popcorn
A large, mushroom shaped kernelled yellow hybrid well suited for caramel corn. Full season. This popcorn is a good yielder with a large pop and excellent flavor. Approximately 8 foot tall plant. 105 days.
  $2.95 per 10g pack ( about 60 seeds )
  1 Ounce pack $6.95
TCB038 Dynamite
Also known as South American Yellow. High yields and great buttery flavor makes this a farmer's market best seller. Sturdy 5 ft. stalks produce 2-3 ears with 12-14 rows of big kernels for easy popping. 110 days.
 11.5g pack ( about 60 seeds per pack ) $2.95
 1 ounce pack ( about 175 seeds per pack ) $6.95
VL373 Strawberry Popcorn
Tiny 2" ears of deep maroon popcorn. A must for flavor and ornamental appeal. 25 seeds per pack.
$2.95 per 1.5g pack ( about 20-25 seeds )
AW59 Shades of Blue
Shades of Blue Mini Indian corn makes a very ornamental fall display as well as a great popcorn. Ears are 3-1/2 to 5-1/2" long. Several blends of blue shades including sky blue and violet blue, contrasted by red and white husks. Also pops with hulless kernels and excellent flavor. 105 days.
  $2.95 per 8g pack ( about 40-45 seeds )
 250 seeeds $5.95
TCB093 Strawberry De-lite Ornamental Popcorn
This beautiful strawberry popcorn has longer ears than the standard, and a striking variety of colors including deep red, light pink, tan, and cream-colored kernels. The strong stalks stand well and offer outstanding yields of these attractive ears with beige husks that are occasionally streaked with red.
A beautiful mix of fall colors make this great for both popping and ornamental use. Produces so many different colors and hues on 3-4 inch pods. 105 days.
 3.2g Package ( about 35 seeds ) $2.95
 250 seeds $7.95
TPF281 Lady Fingers Popcorn
In 1849, a man named Ebenezer Emmons expressed great interest in a delicate variety of popcorn that he named "Lady Fingers." He considered it the best type of popcorn available at that time. Seed experts theorize that this variety originated in South America, since it is quite similar to the popcorn of Argentina and Paraguay.
An heirloom from Amish country, these plants grow slim 6-7 inch ears. The yellow kernels pop into very small, hull-less popcorn bursting with goodness. The very small tender hulless yellow kernels are perfect for those with digestive issues. A dainty looking small popcorn, it may also be used for ornamental purposes.
  3.85g pack ( about 60-70 seeds ) $2.95
  250 seeds $6.95
TCB030 White Hulless Hybrid Popcorn
The best popcorn for first time growers. Small kernels pop up tender with no hard centers. Grows just like sweet corn except let the ears remain on the stalks until they get dry, tan and brittle. 110 days.
  $2.95 per 12g pack ( about 90 seeds )
 1 ounce pack $6.95
TPF204 Robust 997 F1 Hybrid Popcorn
7-8" ears on 8-9' plants with glossy, deep yellow kernels. Its high (45:1) expansion ratio makes it an extremely tender popcorn. Ears may also be used for fall decorating. The best variety for corn shoots.
  $2.95 per 12g pack ( about 100 seeds )
  One ounce pack $5.95