Popcorn -how to grow, harvest


Popcorn is another one of those excellent foods that America gave the world.  As a food popcorn has relatively few calories (until you add butter) yet is filling. There are about 35 calories per cup of popped corn.  It’s high in carbs but does have lots of fiber to lessen that effect.  The little hulls that stick in your teeth can be annoying but if you grow your own popcorn you can grow varieties that are hull-less or at least less annoying.


Americans consume more than 13 billion quarts of popcorn each year.  Popcorn is a fairly cheap snack but you can grow your own supply even cheaper and have lots of fun doing it.  It’s a great garden project for kids.

Choosing what varieties to plant
Choose popcorn sold for seed to plant and don’t try to plant popcorn sold in the store to pop.  It may grow but this popcorn is often old and doesn’t germinate well.  It may not be a good variety for your area either. And growing your own popcorn allows you to choose varieties that taste better, have unusual colors or other qualities that commercial popcorn doesn’t have.  You want to choose a seed popcorn that will have time to mature and dry on the stalk in your growing zone.  In Michigan you can safely choose varieties that mature up to 90 days and in southern areas 100-120 days will probably be fine.

Popcorn stalks are often shorter than other types of corn.  The ears of corn are often smaller and narrower and popcorn varieties often have more ears per stalk than sweet or field corn.  Most have yellow or white kernels although there are colorful varieties of popcorn also. Color doesn’t affect the taste, although some popcorn varieties do taste slightly different than others.

Here are some varieties to consider. Japanese hull-less (white or yellow) – small yellow or white ears, less annoying hulls, and pops nice large kernels.  Open pollinated so seeds can be saved. Miniature Pink- tiny pink ears are pretty, Mini-colored- pretty ears in an assortment of colors but the popped kernels are small, Japanese Striped – a very pretty heirloom popcorn often grown for its variegated, striped foliage.  The ears are small and burgundy colored but popping quality is not the best. Calico- another variety with multicolored kernels, average popping quality and open pollinated. 

Giant Yellow hybrid- the commercial type, large stalks and ears, big fluffy kernels when popped. Snow Puff hybrid – a hull less variety with tender large popped kernels but won’t come true from saved seed. Early Pink- an open pollinated pink that’s good for short seasons and pops into fluffy white kernels. Robust Yellow or Robust White- good commercial types with large ears and kernels.  Strawberry- small red ears. Baby Blue- a  hull-less blue variety with small kernels. Dakota Black- an heirloom open pollinated that has dark red-black kernels.  Mixed Baby Rice is the closest thing to true hull-less popcorn.  The kernels are small and long like rice in a mixture of red, white and striped kernels.  However the popped kernels are small and popping quality only average.

Note- all popcorn looks white or pale yellow when popped.  Traces of colored kernels can remain on the hulls. Hull-less varieties actually do have hulls, they are just smaller, softer and thinner so they don’t stick to the teeth as badly. Popcorn varieties can have slightly different tastes, some are said to have a more “nutty” flavor but the taste range isn’t great.

Planting the popcorn
Anyone who has ever grown sweet corn, and even those who haven’t, can grow popcorn.  A small area, say 4 feet by 20 feet, can grow all the popcorn a small family can use in a year.  Two things are necessary though. Your popcorn patch must be in full sun.  You must also be able to isolate your popcorn patch at least 50 feet from other types of corn, such as sweet corn, field corn or ornamental corns.  Otherwise your popcorn will cross pollinate with the other varieties and probably won’t pop very well.  You’ll probably want to choose only one variety to plant each year, (unless you have lots of room), because different varieties of popcorn will also cross pollinate.

Prepare the popcorn patch by tilling up the soil and removing large rocks to make a smooth seed bed. Fertilize at planting time with a garden fertilizer high in nitrogen (the first number on the bag) such as 15-6-6 or 12-5-5, according to label directions. Corn is a heavy “feeder” and almost always requires fertilization for optimum growth.   A slow release fertilizer is good to use.  Mix the fertilizer into the soil of the bed and don’t sprinkle it into the seed row or holes.  You can actually use grass fertilizer on a popcorn patch because corn is a grass.  But the fertilizer should have no weed killers or pesticides such as grub control because you are going to eat the seeds of this grass.

Plant popcorn after the danger of frost has passed and the soil is warm.  (In Michigan that’s probably mid to late May.)  Any kind of corn does better planted in several short rows in a block rather than one long one row. That’s because corn is pollinated by the wind and in one single row one side of each corn ear often doesn’t get pollinated well, leading to fewer kernels on the ear. Plant the seeds about 6 inches apart in rows a foot apart.  Plant them 1-2 inches deep, deeper in sandy soil, less deep in heavy clay soils.

Some people plant popcorn in mounds or circular patches which is fine.  Some even add beans and squash plants to these patches as the Native Americans sometimes did.  You’ll get better production if you have limited space to grow popcorn if you don’t add these companion plants.

If the weather is dry you may want to water the popcorn patch at least once to get the seeds germinating.  You should see corn sprouting up anywhere from 7-14 days depending on moisture and soil temperatures.

Care of the popcorn patch

Keep young corn weeded as it doesn’t compete well with weeds.  Once it gets about knee high it will smother out most weeds on its own but continue to remove any large weeds that pop up. Healthy corn grows quickly in good weather.  The leaves of healthy corn are dark green, thick and either pointed upwards or drooping in a graceful curve.  If corn leaves roll up the corn needs water.  But if you want the best production don’t wait until the leaves roll up to water.  If it’s warm and dry water the corn once a week. 

Some people “hill” or mound soil around the roots of corn when the corn is 1-2 feet high.  This can help in sandy soil in windy areas to keep large stalks from blowing over.  But in most gardens this isn’t necessary.  If you choose to do this take care not to damage the popcorn roots.  Take the soil from row space.  Don’t mound it higher than about a third of the height of the young corn.

One of the best things you can do to ensure good healthy growth and production of popcorn is to add more nitrogen to your patch when the corn just begins to form tassles at the top. Corn uses a lot of nitrogen.  Corn that isn’t growing quickly and looks yellowish green usually needs more fertilizer.  If you can find just nitrogen – that’s a bag or box with just the first number on it such as 15-0-0 that’s great because the other nutrients are usually ok if you fertilized at planting time.  Sprinkle that fertilizer among the corn stalks or along the edges of the row. Corn can also look yellow if it’s cool and wet but there is generally little you can do in that situation but hope for better weather.

In a garden situation popcorn seldom has any serious pest or disease issues.  Cut worms can be a problem when corn is a few inches high. These cut the stalk at the base and leave the tops lying nearby. In a garden it may be possible to protect each stalk with a 3 inch strip of newspaper around the bottom.  You may want to fence your patch or protect it with electric wire because deer and other critters are fond of young corn too.

Corn earworm seems to be less of a problem in popcorn than sweet corn but the same remedy, a drop of mineral oil at the top of each ear can help.  There are also pesticides you can apply. 

Harvesting popcorn
Popcorn must remain on the stalk until the stalk is brown and dry.  The ears should be covered with dry papery husks. They can remain there through frosts. In late fall, before hard freezes, the ears should be pulled off the stalks.  It’s always best to do this during a stretch of warm dry weather and wait until the dew has dried in the morning before harvesting.  If you must harvest during damp weather you’ll need a warm dry place to spread out the ears and let them dry for a few days.

It’s always best to remove the popcorn husks from the ears and let the ears dry somewhere warm, clean and dry in a single layer for another month or so before taking the kernels off the cob. Some people tie the dry husks together and hang the ears to dry further but this is labor intensive.  Check the corn from time to time and rotate the drying ears if necessary.  Moldy ears should be discarded.

When popcorn is thoroughly dry the kernels should feel hard and look shiny.  Take an ear and remove the kernels.  This is done by loosening them with your nails and pushing them off with the thumb or twisting the ear in your hand while gripping it firmly. (You can buy a shelling hand tool too.) When you have a few tablespoons of kernels do a test pop.  Just pop the corn in the way you generally would pop popcorn.  If the popcorn pops quickly and leaves few “dead soldiers” (un-popped kernels) behind the popcorn has dried enough.  If you have corn drying in different spots you may want to test some kernels from each area.  If the corn doesn’t pop well let it dry for a week or two longer and try again.

Once you know the popcorn is dry and pops well you can remove it all from the cobs. It’s a good activity for cold, early winter nights.  You can store popcorn on the cob but it takes less room if it’s removed and is less work when you want popcorn.  Once popcorn is at perfect popping stage you want to try and maintain the moisture content of the kernels at that stage. You don’t want them to absorb moisture or dry out too much.  Store the kernels (or ears) in clean dry glass or plastic containers.  If moisture appears on the sides of containers after they have set for a few days you must spread the kernels out in a single layer and let them dry again.  Discard any moldy kernels.  Popcorn generally stores well for at least a year, although popping ability will lessen as time goes by.

Your home produced popcorn will probably pop better than that you buy in the store because it’s fresh. Two tablespoons of dry popcorn makes a quart of popped corn.  If you have too much popcorn it can make lovely gifts placed in pretty jars, especially if you grew a colorful variety.  Or donate your excess popcorn to a food pantry.

All through winter you can enjoy a healthy snack from your garden if you grow some popcorn.  It’s always better if you grow it yourself.

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